FXUS63 KDTX 311939 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 339 PM EDT SUN MAR 31 2013 .SHORT TERM...THROUGH TONIGHT DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES SENT A WEAK TROUGH/COLD FRONTAL BOUNDARY THROUGH THE AREA THIS MORNING WITH LITTLE IN THE WAY OF PRECIP ASSOCIATED WITH IT. IMPRESSIVE DRY SLOT BEHIND THE TROUGH WITHIN A REGION OF DEEP MIXING HAS CLEARED OUT MOST OF THE CLOUDS ALLOWING TEMPS TO SPIKE INTO THE MID 50S. THE DEEP MIXING HAS ALSO PRODUCED GUSTS TO AROUND 20 KNOTS THIS AFTERNOON. A STRONGER TROUGH/FRONT WILL GET SENT THROUGH THE REGION THIS EVENING. MODELS INDICATE STEEP LOW LEVEL LAPSE RATES AND CAPE VALUES BETWEEN 50-100 J/KG WITH A NARROW BAND OF THETA E JUST AHEAD OF THE TROUGH. THEY ALSO SHOW FAIRLY LOW PWATS TIED IN THE LOW LEVELS BRIEFLY SPIKING WITH THE THETA E AXIS BUT DRYING OUT RAPIDLY BEHIND THE TROUGH. THE HRRR AND HIRES WRF BOTH SHOW A PERIOD OF SHOWERS...RAIN BECOMING A MIX OF RAIN AND SNOW...BETWEEN 00Z AND 06Z WITH POSSIBLE FLURRIES OR LIGHT SNOW SHOWERS AFTER THAT. AN AREA OF PRECIP IS CURRENTLY SHOWING UP ON REGIONAL RADAR WITHIN THE TROUGH SO BESIDES FINE TUNING SOME TIMING ISSUES...SEE NO REASONS TO CHANGE MUCH WITH THE OVERNIGHT POPS/WX. WITH THE POSSIBLE CONVECTIVE NATURE OF THE PRECIP AND LONGER DURATION...WILL LEAVE A FEW TENTHS OF SNOW ACCUMULATIONS TO THE NORTH. WINDS WILL STAY ELEVATED OVERNIGHT WHICH WOULD TYPICALLY LEAD TOWARD WARMER MIN TEMPS BUT CAA BEHIND THE TROUGH WILL DROP 850MB TEMPS FROM +1C TO -11C OVERNIGHT. DEWPOINTS UPSTREAM IN THE TEENS WILL TRY TO WORK THEIR WAY INTO THE SAGINAW VALLEY AS WELL SO WE WILL STILL COOL OFF QUITE A BIT TONIGHT. && .LONG TERM... MONDAY THROUGH NEXT SUNDAY POLAR AIR NOW INFILTRATING THE UPPER MS VALLEY WILL BE OVER THE GREAT LAKES REGION BY MONDAY MORNING. THIS AIRMASS IS ASSOCIATED WITH A POLAR VORTEX NOW LOCATED OVER NRN ONTARIO. THIS UPPER LOW IS FORECAST TO DEEPEN AS IT TRACKS NORTHEAST OF LAKE HURON AND INTO QUEBEC ON MONDAY AND WILL REMAIN RATHER PROGRESSIVE...LIFTING INTO NEWFOUNDLAND BY MIDWEEK. BY 12Z MON...850MB TEMPS ARE STILL FORECAST TO PLUNGE TO -12 TO -14C OVER SE MI. WEAK MID LEVEL IMPULSES TRACKING INTO THE REGION TUES/TUES NIGHT WILL HOLD SOME DEGREE OF MID LEVEL TROUGHING OVER THE GREAT LAKES...WITH SE MI REMAINING FIRMLY WITHIN THE LOW LEVEL THERMAL TROUGH. DESPITE SOME INTERVALS OF SUN AND MIXING HEIGHTS EXTENDING UP TO 800MB...THE DEPTH OF COLD AIR WILL REMAIN SUPPORTIVE OF DAYTIME HIGHS MON AND TUES MAINLY IN THE 30S. NIGHTTIME MINS ARE EXPECTED TO DROP OFF INTO THE 20S /POSSIBLY SOME TEENS IF THE BOUNDARY LAYER CAN DECOUPLE/. THESE TEMPS ARE A GOOD 10 TO 15 DEGREES BELOW SEASONAL AVERAGES. W-NW WINDS WILL BE QUITE GUSTY ON MONDAY AS DEEPENING SFC LOW PRESSURE OVER QUEBEC SUSTAINS A TIGHT LOW LEVEL GRADIENT OVER THE REGION. SOME GUSTINESS TO THE WINDS IS LIKELY TO HOLD THROUGH MUCH OF TUESDAY AS THE LAKE AGGREGATE MAINTAINS A HEALTHY GRADIENT OVER SRN LOWER MI. THIS WILL PUT WIND CHILL READINGS IN THE TEENS AND 20S MON AND TUES. THE STEEP LOW LEVEL LAPSE RATES COURTESY OF THE COLD AIR WILL ALLOW A DIURNAL ENHANCEMENT TO THE CLOUDS MON AND TUES AFTERNOON. THE CORE OF THE MID LEVEL COLD POOL WILL HOWEVER TRACK TO THE NORTHEAST OF THE FORECAST AREA...THUS KEEPING CONVECTIVE CLOUD DEPTHS RATHER SHALLOW UNDER A MID LEVEL INVERSION. THIS ALONG WITH SUBSTANTIAL LOW LEVEL DRY AIR ADVECTION WILL SUPPORT JUST SCATTERED SNOW SHOWERS ON MONDAY. THE 12Z MODEL SUITE DO SHOW A MID LEVEL IMPULSE /NOW LOCATED OVER FAR NORTHERN CANADA/ DIVING INTO THE WESTERN GREAT LAKES LATE TUES. THE CURRENT MODEL SUITE SUGGEST THIS FEATURE WILL ARRIVE INTO SE MI TOWARD THE END OF THE DIURNAL CYCLE...WHICH SUPPORTS HOLDING ONTO THE DRY FORECAST AT THIS TIME. A SPLIT FLOW PATTERN IS FORECAST ACROSS NORTH AMERICA BY MID-LATE NEXT WEEK...WITH A FAST MOVING NORTHERN STREAM WAVE EXPECTED TO BRING A COLD FRONT INTO SRN MI IN THE THURS NIGHT/FRIDAY TIME FRAME. STEADY WARM AIR ADVECTION WILL ALLOW TEMPS TO RISE BACK UP INTO THE 50S ON THURSDAY PRIOR TO THE COLD FRONT PASSAGE. WHILE THE MEDIUM RANGE MODEL SUITE ARE IN GOOD AGREEMENT IN SHOWING A STRONG LOWER TROPOSPHERIC BAROCLINIC ZONE SETTING UP ACROSS THE NRN PLAINS AND GREAT LAKES REGION BY NEXT WEEKEND...THERE IS CONSIDERABLE DIFFERENCES WITH RESPECT TO THE TIMING AND AMPLITUDE OF MID LEVEL SHORT WAVE ENERGY EMANATING FROM THE PACIFIC AND TRACKING ALONG THE BAROCLINIC ZONE. LARGE SPREAD AMONG ENSEMBLE MEMBERS ADDS TO THE UNCERTAINTY. THERE IS HOWEVER ENOUGH CONFIDENCE TO CARRY A CHANCE OF PRECIP NEXT WEEKEND. && .MARINE... DEEPENING LOW PRESSURE SYSTEM OVER THE NORTHERN GREAT LAKES WILL DROP THE SECOND OF TWO SURFACE TROUGHS THROUGH THE GREAT LAKES THIS EVENING...USHERING A MUCH COLDER AIRMASS INTO THE REGION. STRONG WESTERLY WINDS WILL VEER TO THE NORTHWEST BEHIND THIS TROUGH AND INCREASE WITH A TIGHTENING PRESSURE GRADIENT...ESPECIALLY OVER THE NORTHERN HALF OF LAKE HURON OVERNIGHT. A GALE WARNING HAS BEEN ISSUED FOR THE OPEN WATERS OF NORTHERN LAKE HURON WITH SMALL CRAFT ADVISORIES FOR ALL NEARSHORE WATERS OF LAKE HURON. WINDS WILL REMAIN ELEVATED THROUGH MONDAY NIGHT. && .AVIATION...ISSUED 137 PM EDT SUN MAR 31 2013 //DISCUSSION... LINGERING MVFR CIGS WILL LIFT TO VFR AS MIXING INCREASES THIS AFTERNOON. THE DEEP MIXING WILL ALLOWS WINDS TO GUST UP 25 KNOTS INTO THIS EVENING. THE SECOND COLD FRONT OF THE DAY WILL DROP THROUGH SE MI LATE THIS EVENING VEERING WINDS TO NW AND POSSIBLY PRODUCING SOME LIGHT RAIN SHOWERS THIS EVENING OR A RAIN/SNOW MIX OVERNIGHT...WHILE DROPPING CIGS BACK TO MVFR. COVERAGE AND CONFIDENCE OF PRECIPITATION TOO LOW TO INCLUDE IN THE TAFS ATTM. THE STRONG COLD FRONT WILL ALLOW WINDS TO STAY ELEVATED THROUGH THE NIGHT. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE THAT CEILINGS WILL FALL BELOW 5000 FEET THIS EVENING THROUGH MONDAY MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...FROM 10 PM SUNDAY TO 10 PM MONDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...FROM 10 PM SUNDAY TO 8 AM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT HURON...FROM 4 AM MONDAY TO 8 AM TUESDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 4 AM MONDAY TO 10 PM MONDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DRK LONG TERM....SC MARINE.......DRK AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 011953 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 353 PM EDT MON APR 1 2013 .SHORT TERM...THIS EVENING AND TONIGHT THE POLAR VORTEX NOW ROTATING INTO SOUTHERN QUEBEC HAS ADVECTED A BITTER COLD AIRMASS FOR EARLY APRIL STANDARDS ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION. THE COLD FRONT WHICH TRAVERSED THE FORECAST AREA LAST EVENING IS IN FACT ALREADY ADVANCING INTO THE DEEP SOUTH. EVEN WITH SOME INTERVALS OF SUNSHINE TODAY...TEMPS FOR THE MOST PART HAVE REMAINED STUCK IN THE 30S. THE BRISK W-NW WINDS /GUSTING UP TO 30 MPH AT TIMES/ HAVE HELD WIND CHILLS IN THE 20S. THE POLAR VORTEX WILL REMAIN RATHER PROGRESSIVE AS IT ROTATES ACROSS QUEBEC TONIGHT. 12Z RAOBS HOWEVER SHOWED 850MB TEMPS DOWN TO -12 TO -15 C FROM THE GREAT LAKES ALL THE WAY TO THE EASTERN DAKOTAS. PERSISTENT W-NW FLOW TONIGHT WILL ACTUALLY ALLOW SOME WEAK LOW LEVEL COLD AIR ADVECTION TO PERSIST. THE STRATO CU FIELD WHICH DEVELOPED THIS AFTERNOON WILL LIKELY DIMINISH WITH THE LOSS OF DIURNAL HEATING. WHILE THE AIRMASS WILL REMAIN COLD ENOUGH TO GENERATE SOME LAKE CLOUDS OFF LAKE MI UNDER THE W-NW FLOW...THE AIRMASS IS VERY DRY UPSTREAM OF THE LAKE. ALTHOUGH A HIGH BASED INVERSION /6-7K FT/ WILL PERSIST THROUGH THE NIGHT...THE DEGREE OF DRY AIR SUGGESTS SOME SUBSTANTIAL BREAKS IN THE CLOUD COVER THROUGH THE NIGHT. THE WINDS WILL WEAKEN A BIT THIS EVENING AS THE DIURNAL HEATING CYCLE WANES. SOME LAKE AGGREGATE TROUGHING WILL HOWEVER PERSIST...WHICH WILL MAINTAIN AT LEAST A 6-10 KNOT WIND THROUGH THE OVERNIGHT. WHILE THIS WILL SUPPRESS THE DEGREE OF DECOUPLING SOMEWHAT...THE POTENTIAL FOR AT LEAST PARTIAL CLEARING SUPPORTS MIN TEMPS DOWN INTO THE 20S /WITH SOME TEENS POSSIBLE OUTSIDE OF THE DETROIT URBAN AREA/. SHALLOW CONVECTIVE CLOUD DEPTHS AND DRY LOW LEVEL AIR HAVE KEPT THE INTENSITY OF THE DIURNAL SNOW SHOWERS TO MAINLY FLURRIES...WHICH WILL DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME INSOLATION. && .LONG TERM...TUESDAY THROUGH SUNDAY LONGWAVE PATTERN TO UNDER GO FAVORABLE CHANGE THIS WEEK AS POLAR JET LIFTS BACK TO THE NORTH AND THE GREAT LAKES ARCTIC TROUGH PROGRESSES EASTWARD RESULTING IN NEARLY ZONAL FLOW ACROSS THE NORTHERN CONUS. THIS WILL ALLOW TEMPERATURES TO MODERATE BY LATE IN THE WEEK AND RETURN BACK INTO THE 50S. THERE ARE A FEW THINGS WATCH IN THE EXTENDED PERIOD STARTING WITH A COMPACT VORT MAX DIVING DOWN THE BACKSIDE OF THE TROUGH AS IT PULLS AWAY FROM THE REGION ON WEDNESDAY. MODELS 12Z MODEL RUNS ARE FAIRLY SIMILAR TRACKING THIS SHORTWAVE RIGHT DOWN THE LAKE HURON FETCH BETWEEN 09Z AND 18Z WEDNESDAY. THE GEM IS ONE OF THE OUTLIERS WITH AN TRACK FURTHER EAST OVER ONTARIO/QUEBEC AND THE NAM JUMPED IN LINE WITH THE 12Z RUN WITH A MORE WESTERN TRACK. THE FORCING COMBINED WITH THE NORTHERLY FLOW AND COLD AIR...-10 TO -15C AT 850MB...WOULD HAVE A CHANCE TO PRODUCE SOME LAKE EFFECT OVER LAKE HURON DOWN INTO THE THUMB EARLY WEDNESDAY. THE PROBLEM IS THAT A LARGE AND STRONG SFC HIGH WILL BE BUILDING INTO THE REGION FROM THE NORTHERN PLAINS WITH A MIDLEVEL RIDGE OVERHEAD. THE STRENGTH OF THESE...AND THE SUBSIDENCE/DRY AIR WILL MAKE IT VERY HARD FOR ANY PRECIP TO DEVELOP OVER THE AREA. IN ADDITION...IF THE FLOW IS BACK TO THE NW JUST A BIT...THE LAKE EFFECT WILL MISS US AND HEAD TO SOUTHERN ONTARIO. AT THIS POINT KEPT THE ZONES DRY BUT ADDED A CHANCE POP OVER LAKE HURON. THIS ALSO PRESENTS AN ISSUE FOR MAX TEMPS ON WEDNESDAY. PERSISTENCE HAS SHOW TEMPS OVERACHIEVING OF LATE WITH ANY BIT OF SUNLIGHT...BUT POSSIBLE CLOUDS WITH THE TROUGH MAY BE ENOUGH TO KEEP TEMPS TAMED A BIT. SO WENT A LITTLE CONSERVATIVE WITH MAXES...ESPECIALLY FURTHER NORTH AND EAST...BUT THERE IS A DECENT CHANCE WE WILL STAY MOSTLY SUNNY AND WILL NEED TO BUMP TEMPS UP A COUPLE DEGREES. THE NEXT UPPER LEVEL FEATURE WILL TRACK ACROSS SOUTHERN CANADA WHICH WILL NUDGE THE POLAR JET BACK TOWARD LOWER MI WHILE DROPPING A COLD FRONT INTO THE REGION. MAIN BAROCLINIC ZONE WILL SETTLE SOMEWHERE ACROSS CENTRAL MI LEADING TO A DECENT TEMPERATURE GRADIENT NORTH/SOUTH ACROSS THE STATE. AT THIS POINT THE FRONT LOOKS TOO WEAK AND DRY...A SOUTHERN STREAM WAVE WILL BE PREVENTING ANY MOISTURE FROM REACHING THE AREA...TO DO MUCH OVER THE AREA BESIDE PRODUCE SOME CLOUDS AND DROP TEMPS A FEW DEGREES. THE WEEKEND LOOKS TO BE ON THE WET SIDE AS WAVE TRACKS ACROSS THE NORTHERN PLAINS AND THROUGH LOWER MI. A WARM FRONT WILL LIFT THROUGH SE MI SATURDAY MORNING WITH GOOD FEED OF MOISTURE FROM THE GOM. RAIN WILL DEVELOP ALONG THE WARM FRONT ON SATURDAY AND THE COLD FRONTAL PASSAGE ON SUNDAY. && .MARINE... AVAILABLE MARINE OBSERVATIONS HAVE NOT BEEN SUPPORTIVE OF GALES OVER LAKE HURON THIS AFTERNOON. HOWEVER...THERE HAS BEEN A SLIGHT UPTICK IN OBSERVED WINDS NORTH OF THUNDER BAY. THIS IS LIKELY THE RESULT OF A DEVELOPING TROUGH OVER CENTRAL LAKE HURON DUE TO SOME THERMAL ENHANCEMENT OFF THE LAKE. THIS MAY PROVIDE ENOUGH OF AN ENHANCEMENT TO THE WINDS NORTH OF STURGEON POINT TO SUSTAIN A FEW GUSTS TO GALES DURING THE EVENING. THE GALE WARNING SOUTH OF STURGEON POINT WILL HOWEVER BE CANCELLED. THERE WILL REMAIN A RESPECTABLE NORTHWEST GRADIENT OVER LAKE HURON THROUGH TUESDAY AS THE TROUGH LINGERS OVER THE EASTERN LAKES. THE AIRMASS IS COLD ENOUGH TO SUCH A DEGREE THAT UNSTABLE CONDITIONS WILL PREVAIL THROUGH MID WEEK. THE WINDS WILL WEAKEN LATE WED INTO WED NIGHT AS HIGH PRESSURE TRACKS OVERHEAD. SOUTHWEST FLOW WILL IMMEDIATELY DEVELOP WITHIN THE RETURN FLOW OF THE SURFACE HIGH BY THURSDAY. LOW LEVEL WARM AIR ADVECTION WILL INCREASE THE STABILITY OVER THE LAKES BY THIS TIME...KEEPING WIND GUSTS IN CHECK. && .AVIATION...ISSUED 1251 PM EDT MON APR 1 2013 //DISCUSSION... A DEEP WELL MIXED BOUNDARY LAYER WILL SUSTAIN WIND SPEEDS IN THE 14 TO 18 KNOT RANGE THROUGH THE REST OF THE AFTERNOON WITH GUSTS EXCEEDING 25 KNOTS AT TIMES. THE LOSS IN DAYTIME HEATING WILL LEAD TO A SLIGHT DECOUPLING OF THE BOUNDARY LAYER AROUND 00Z...WHICH WILL CAUSE THE WINDS TO LOOSE THE GUSTINESS. FURTHER DECOUPLING DURING THE OVERNIGHT WITH AT LEAST PARTIAL CLEARING EXPECTED WILL LIKELY CAUSE THE WIND SPEEDS TO DROP OFF BELOW 12 KNOTS. GIVEN THE HIGH INVERSION HEIGHTS...CEILINGS WILL REMAIN IN THE VFR CATEGORY THROUGH THE TAF PERIOD. FOR DTW...WHILE CEILINGS WILL REMAIN AROUND 5K FT FOR THE NEXT COUPLE OF HOURS...A DEEPENING BOUNDARY LAYER AND VERY DRY LOW LEVEL AIR SHOULD LIFT BASES UP TO 6K FT. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILINGS BELOW 5000 FT AFTER 20Z TODAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362...UNTIL 2 AM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 5 PM TUESDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL MIDNIGHT TUESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....DRK MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 081422 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1022 AM EDT WED MAY 8 2013 .UPDATE... TEMPS HAVE BEEN WARMING CONSIDERABLY OVER THE COUPLE OF HOURS. GIVEN THE PRESENCE OF SOME MID LEVEL MOISTURE...ENHANCED HIGH BASED CU IS EXPECTED AGAIN THIS AFTERNOON. THEREFORE...CURRENT FORECAST HIGHS IN THE MID TO UPPER 70S ACROSS MOST OF THE FORECAST AREA LOOK REASONABLE. THE 12Z DTX SOUNDING SHOWED A NARROW LAYER OF MOISTURE CENTERED NEAR 700 MB. THE 12Z DTX SOUNDINGS AND LATEST MODEL SOUNDINGS SUGGEST CONVECTIVE CLOUD DEPTHS THIS AFTERNOON SHOULD BE SUFFICIENT ENOUGH TO GENERATE SOME ISOLATED/SCATTERED SHOWERS. WHILE SOME ISOLATED THUNDERSTORMS WOULD NOT BE OUT OF THE QUESTION...THE LOWEST 6K FT WILL BE QUITE DRY...THUS LIMITING ML CAPE CONSIDERABLY. MID LEVEL LAPSE RATES WILL NOT TOO TERRIBLY STEEP AS WELL. THUS WILL NOT INCLUDE ANY THUNDER MENTION AT THIS TIME. THE MAIN CHANGE IN THE UPDATE WILL BE TO INCREASE POPS ACROSS MONROE/WAYNE/MACOMB/ST CLAIR COUNTIES WHERE LAKE BREEZE CONVERGENT BOUNDARIES WILL PROVIDE SOME ENHANCED LIFT. && .AVIATION...ISSUED 629 AM EDT WED MAY 8 2013 //DISCUSSION... A VORTICITY SPOKE ASSOCIATED WITH LARGE LOW PRESSURE SYSTEM WELL TO THE SOUTHEAST WILL MAINTAIN ENHANCED MID/UPPER LEVEL CLOUDS AT TIMES TODAY WITH A FEW SHOWERS ALSO POSSIBLE THIS AFTERNOON AS LIFT FROM THIS FEATURE COMBINES WITH DAYTIME HEATING TO ENHANCE THE DIURNAL CUMULUS FIELD. ANY ENHANCED CLOUDS AND SPOTTY SHOWERS WILL FADE IN THE EVENING WITH THE LOSS OF HEATING. WINDS WILL REMAIN LIGHT THIS FORECAST PERIOD AND RATHER CHAOTIC AS PRESSURE GRADIENT REMAINS VERY WEAK. //DTW THRESHOLD THREATS... * NONE && .PREV DISCUSSION...ISSUED 313 AM EDT WED MAY 8 2013 SHORT TERM...TODAY AND TONIGHT VORTICITY SPOKE WILL ACTUALLY ROTATE BACK WESTWARD INTO THE AREA AROUND UPPER LOW POSITIONED WELL OFF TO THE SOUTHEAST. THIS WILL PROVIDE MINOR LIFT ACROSS THE AREA TODAY AND ENHANCE ANY DIURNAL CUMULUS THAT FORMS BY MIDDAY. WHILE LOW LEVEL CONVERGENCE REMAINS RATHER WEAK AND LOW LEVEL MOISTURE REMAINS SCARCE...IT APPEARS THIS ADDED LIFT...COMBINED WITH THE HIGHER MID/HIGH LEVEL MOISTURE THAT HAS WORKED INTO THE AREA DURING THE PAST 24 HOURS WILL BE ENOUGH TO PRODUCE SCATTERED/WIDELY SCATTERED SHOWERS DURING THE AFTERNOON AS MAXIMUM HEATING/INSTABILITY IS ACHIEVED. ANY ACTIVITY THAT DOES DEVELOP WILL FADE VERY QUICKLY DURING THE EVENING WITH THE LOSS OF HEATING WITH DRY WEATHER EXPECTED OVERNIGHT TONIGHT. WILL REFINE THE TIMING OF THE POTENTIAL SHOWERS TO LIMIT THIS ACTIVITY TO THE 16Z-00Z TIME FRAME AND INCREASE THE COVERAGE BASED ON 00Z MODELS/GUIDANCE. AS FOR TEMPERATURES...HIGHS WILL ONCE AGAIN CLIMB INTO THE 70S WITH THE WARMEST READINGS OVER THE GENESEE/SAGINAW VALLEY AND THE COOLEST READINGS IMMEDIATELY DOWNWIND OF THE GREAT LAKES. LOWS TONIGHT WILL ALSO BE PREDICTABLE...RANGING MAINLY BETWEEN 45-50 DEGREES FROM I 69 NORTH AND 50 TO 55 FURTHER SOUTH. LONG TERM...THURSDAY THROUGH TUESDAY THE CONVOLUTED UPPER AIR PATTERN OVER THE WESTERN AND CENTRAL UNITED STATES IS BEGINNING TO CONSOLIDATE AS THE CUTOFF CIRCULATION OVER THE NORTHERN PLAINS OPENS IN RESPONSE TO APPROACHING NORTHERN ENERGY. MEANWHILE, THIS MORNING'S SATELLITE IMAGERY SHOWS DEEP MOISTURE CHARACTERIZED BY 1.30+" PWATS BEGINNING TO DRAW NORTH AND POOL ALONG THE ORGANIZING/ELONGATING SURFACE TROUGH OVER THE SOUTHERN PLAINS. THE GRADUALLY EVOLVING/ORGANIZING MID-LEVEL TROUGH STRUCTURE WILL ALLOW A SIGNIFICANT PORTION OF THIS MOISTURE TO BE DRAWN NORTHEASTWARD AS THE AFOREMENTIONED OPENING/FLATTENING WAVE RIPPLES ALONG WITHIN THE DEVELOPING SW FLOW ALOFT. THIS WILL INITIALLY BE MANIFESTED IN THE FORM OF INCREASING CLOUD COVERAGE AND PERHAPS A FEW SHOWERS DEVELOPING LATE IN THE DAY ON THURSDAY...ESPECIALLY ALONG LAKE BREEZE BOUNDARIES. HOWEVER, THE BULK OF THE DAY IS LIKELY TO BE DOMINATED BY PERSISTENT WSW FLOW AND THE RETURN OF TEMPS WELL INTO THE 70S. THE LION'S SHARE OF RAINFALL WILL COME LATE THURSDAY NIGHT AS THE TIGHTENING UPPER MASS GRADIENT NORTH OF LAKE HURON ELICITS RAPID DEVELOPMENT OF A 90KT JET STREAK. THE RESULTANT UPTICK IN SFC-500MB RIGHT ENTRANCE FGEN SHOULD PROMOTE A HEALTHY AND WIDESPREAD CONVECTIVE RESPONSE WITHIN THE RESIDENT WEAKLY STABLE/CONDITIONALLY UNSTABLE AIRMASS. ALTHOUGH A FEW RUMBLES OF THUNDER CANNOT BE RULED OUT, DEEP MOISTURE WILL TEND TO FAVOR MOIST ADIABATIC LAPSE RATES FOR THE BULK OF THE OVERNIGHT HOURS. THE DURATION OF SHOWERS WILL BE PROLONGED THROUGH AT LEAST THE FIRST HALF OF FRIDAY AS A SHALLOW SFC-900MB BACKDOOR COLD FRONT SURGES SOUTHWARD ACROSS LOWER PENINSULA BEFORE THE DEEPER MOISTURE EXITS TO THE EAST. THE TIMING OF THE FRONT WILL BECOME IMPORTANT BY FRIDAY AS MAX TEMPS WILL BE SENSITIVE TO PRECIP DURATION ALONG THE BACKDOOR FRONT. THE CURRENT FORECAST LEANS TOWARD A SLOWER GFS/ECMWF CONSENSUS AND HIGHS ONLY REACHING AROUND 60 DEGREES AS A RESULT. THE FRONT WILL ALSO SERVE AS A FOCUS FOR DIURNAL CONVECTION BY FRIDAY AFTERNOON. AT THIS TIME, HOWEVER, NO ARGUMENT WITH NWP CONSENSUS WHICH PLACES THE BOUNDARY TO OUR SOUTHEAST BY THAT TIME. LOOKING AHEAD TO THE WEEKEND, THE PV MERGER LONG PROGGED TO TAKE PLACE OVER THE NORTHWEST TERRITORIES LATE THIS EVENING WILL SET THE STAGE FOR SIGNIFICANT LONGWAVE TROUGH AMPLIFICATION OVER THE GREAT LAKES THIS WEEKEND. AN IMPRESSIVE CORRIDOR OF MID-LEVEL HEIGHT FALLS AND ATTENDANT STRONG SURFACE COLD FRONT WILL SWEEP ACROSS SOUTHEAST MICHIGAN ON SATURDAY. H85 TEMPERATURES FALLING FROM AROUND +7C TO -7C DURING THE FOLLOWING 24 HOURS, PER 00Z PROGS, WILL RESULT IN FALLING TEMPERATURES FOLLOWED BY A COLD AND BREEZY MOTHER'S DAY LIKELY TO BE DOMINATED BY BOUNDARY LAYER STRATOCU, A MODEST COVERAGE OF SHOWERS, AND HIGH TEMPERATURES IN THE 40S FOR MOST OF THE DAY. CERTAINLY CAN'T RULE OUT A FEW SNOWFLAKES ACROSS THE FAR NORTH LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING AS THE LAKE ENHANCEMENT KICKS INTO HIGH GEAR. FROST WILL BE A DECISION POINT IN THE FORECAST FOR SUNDAY NIGHT. AT THIS TIME, WARM AND POTENTIALLY WET GROUND COMBINED WITH DISPLACEMENT OF CENTER OF HIGH PRESSURE OVER MISSOURI LEADS TO VERY LOW CONFIDENCE IN FROST FORMATION. WILL THEREFORE MOVE FORWARD WITH FORECAST TEMPERATURES IN THE LOW 30S WITHOUT A MENTION OF FROST. THE HIGH AMPLITUDE RIDGE IN PLACE OVER THE WESTERN U.S. LEADING UP TO THIS POINT WILL STAND LITTLE CHANCE AGAINST THE NEXT ROUND OF STRONG PAC ENERGY PROGGED TO TAKE AIM ON THE PAC NW EARLY NEXT WEEK. THE RESULTANT FLATTENING OF THE PATTERN SHOULD PUT SOUTHEAST MICHIGAN IN A GOOD POSITION TO SEE A QUICK REBOUND IN TEMPERATURES TO AROUND 70 BY TUES AND POTENTIALLY APPROACHING 80 BY WED. MARINE... TRANQUIL CONDITIONS WILL CONTINUE TODAY INTO THURSDAY WITH JUST A SLIGHT INCREASE IN SHOWER CHANCES AS MOISTURE SLOWLY INCREASES OVER THE AREA. WINDS WILL REMAIN GENERALLY 10 KNOTS OR LESS. INCREASED NORTHEAST FLOW IS STILL EXPECTED ON FRIDAY AS A BACKDOOR COLD FRONT SHIFTS THROUGH THE AREA. MODELS ARE IN BETTER AGREEMENT IN BRINGING A LOW PRESSURE SYSTEM IN THE AREA DURING THIS TIME FRAME AND WHILE THERE IS VARYING DEGREES OF CONVECTIVE CONTAMINATION IN TERMS OFF THE INTENSITY OF THIS SYSTEM...IT APPEARS MORE LIKELY THAT THIS LOW WILL ACT TO TIGHTEN THE PRESSURE GRADIENT AND HENCE NORTHEAST FLOW. THIS WILL LEAD TO BUILDING WAVES AND POSSIBLE SMALL CRAFT ADVISORY CONDITIONS. IN ADDITION...SHOWER CHANCE WILL INCREASE SIGNIFICANTLY WITH THE PASSAGE OF THIS SYSTEM...ESPECIALLY FROM SOUTHERN LAKE HURON TO LAKE ERIE. MORE UNSETTLED WEATHER CAN ALSO BE EXPECTED INTO THE WEEKEND AS A STRONG COLD FRONT MOVES THROUGH THE REGION ON SATURDAY AS A VIGOROUS NORTHERN STREAM STORM TRACKS ACROSS CANADA. WHILE PRECIPITATION WILL BE LIMITED WITH THIS FRONT...GUSTY WINDS CAN BE EXPECTED IN ITS WAKE AS MUCH COLDER AIR SPILLS INTO THE REGION. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....DG SHORT TERM...DG LONG TERM....JVC MARINE.......DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 082001 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 401 PM EDT WED MAY 8 2013 .SHORT TERM...THIS EVENING AND TONIGHT THE VISIBLE SATELLITE LOOP HAS BEEN SHOWING ENHANCED DEVELOPMENT OF AN ALTO CU FIELD ACROSS LOWER MI. WHILE INITIAL DEVELOPMENT OF THE DIURNALLY DRIVEN CU FIELD OCCURRED OVER THE HIGHER TERRAIN IN THE IRISH HILLS FROM JACKSON UP TO LAPEER...DEVELOPMENT HAS SINCE BEEN OCCURRING ACROSS THE REST OF THE FORECAST AREA WITH THE EXCEPTION OF LOCALS DOWNWIND OF THE LAKES HURON AND ERIE STABLE LAYERS. A SURGE IN DEEPER MID LEVEL MOISTURE TRANSPORT WITHIN A MID LEVEL IMPULSE ROTATING AROUND THE UPPER LOW OVER VIRGINIA HAS BOLSTERED CONVECTION IN ONTARIO...JUST EAST OF PORT HURON. WHILE THE BETTER LARGER SCALE FORCING WILL REMAIN EAST OF SE MI THIS EVENING...RECENT SATELLITE AND RADAR TRENDS CONTINUE TO SUGGEST SOME INTERACTION WITH THE MID LEVEL MOISTURE TRANSPORT TO SUSTAIN SOME ISOLATED TO SCATTERED SHOWERS INTO EARLY EVENING. VERY LARGE SFC DEWPOINTS DEPRESSIONS ILLUSTRATE THE DEGREE OF LOW LEVEL DRY AIR WHICH WILL LIMIT THE OVERALL COVERAGE AND DURATION OF CONVECTION. AN ISOLATED THUNDERSTORM CAN NOT BE RULED OUT THIS EVENING...MAINLY ACROSS THE FAR EAST DUE TO STRONGER LAKE BREEZE CONVERGENCE AND SLIGHTLY BETTER CONVECTIVE CLOUD DEPTHS. THE LOSS OF DAYTIME HEATING AND A PUSH OF THE LAKE HURON STABLE LAYER FARTHER INLAND WILL ALLOW CONVECTION TO RAPIDLY DIMINISH EARLY THIS EVENING. A REGION OF MID LEVEL SUBSIDENCE ASSOCIATED WITH A SHORT WAVE MID LEVEL RIDGE NOW ADVANCING TOWARD SRN LAKE MI WILL OVERSPREAD SE MI OVERNIGHT. THIS WILL LEAD TO AN OVERALL CLEARING TREND DURING THE COURSE OF THE NIGHT. THE WEAK GRADIENT AND AMPLE LOW LEVEL DRY AIR WILL SUPPORT GOOD RADIATIONAL COOLING AND THUS ANOTHER COOL NIGHT WITH LOWS DROPPING BACK INTO THE 40S AND 50S. && .LONG TERM...THURSDAY THROUGH TUESDAY THE AXIS OF MIDLEVEL SHORTWAVE RIDGING WILL REMAIN WEST OF SOUTHEASTERN MICHIGAN THROUGH THURSDAY AFTERNOON. SIMILAR TO THIS AFTERNOON...ISOLATED SHOWERS AND THUNDER WILL BE POSSIBLE BY LATE AFTERNOON AS A POCKET OF STEEP MIDLEVEL LAPSE RATES WILL RESIDE IN THE 825-600MB LAYER. NWP IS HINTING AT SOME CYCLONIC VORTICITY WASH ACROSS THE AREA DURING THE AFTERNOON. BEST POTENTIAL MAY EXIST ALONG LAKE BREEZE CONVERGENCE BOUNDARIES. PREFERRED WARMER FOR THURSDAY AFTERNOON WITH HIGHS PUSHING UP AGAINST THE 80 DEGREE MARK IN MANY AREAS. WIDESPREAD PRECIPATION POTENTIAL WILL THEN INCREASE DRAMATICALLY FOR THE LATTER HALF OF THURSDAY NIGHT THROUGH MIDDAY FRIDAY. DYNAMICS FOR THE SYSTEM AS A WHOLE LOOK QUITE GOOD WITH A FAIR TO HIGH AMOUNT OF CONFIDENCE. NWP IS SHOWING THE PV/DEFORMATION RIBBON EJECTING NORTHWARD ACROSS TEXAS WILL SNEAK AHEAD OF THE SOUTH DAKOTA FEATURE LATE TONIGHT. A NOTED 1000-500MB HEIGHT FALL BULLSYE IS THEN EXPECTED TO CHARGE THROUGH THE GREAT LAKES REGION BY FRIDAY. QUITE THE SERIES OF EVENTS...AS IT IS VERY OPPORTUNISTIC IN ESSENTIALLY JUMPING FROM THE SOUTHERN STREAM TO THE NORTHERN STREAM. GIVEN TRAJECTORIES OF THE FEATURES IN COMBINATION WITH QUALITATIVE VIEW OF OVERALL HEIGHT PATTERNS INVOLVED...FEEL THE LIKELY TRAJECTORY FOR THE DEEPENING SURFACE LOW WILL BE SOUTH OF LOWER MICHIGAN WITH A BROADER TROUGH EXTENING NORTHWARD INTO THE DOWNRIVER AREA. TRACK OF CVA AND BEST FRONTOGENETIC SUPPORT IS EXPECTED TO BE OVER SOUTHEASTERN MICHIGAN...DISCOUNTING THE GFS SOLUTION. LAPESE RATES WILL BE NEAR MOIST ADIABATIC WHICH SUGGESTS THUNDER WILL BE POSSIBLE...MAIN INSTABILITY WILL RESIDE TO THE SOUTHEAST OF THE STATE. DEGREE OF FRONTOGENTIC AND DEFORMATION FORCING IN COMBINATION WITH MOIST ADIABATIC LAPSE RATES SUPPORTS A GOOD .5 INCH IN LIQUID. THE MAIN COLD FRONT WILL PLOW THROUGH SOUTHEASTERN MICHIGAN LATE SATURDAY AFTERNOON. THIS WILL LEAD TO COOL TO COLD CONDITIONS FOR SUNDAY AS 850MB TEMPERATURES FALL FROM -2 TO -5 DEGREES C. RATCHETED UP POPS FOR SUNDAY AFTERNOON GIVEN SUPPORT FOR DIURNAL INSTABILITY SHOWERS. HIGHS SUNDAY SHOULD PUSH INTO THE LOER 50S DETROIT METRO AREA AND STRUGGLE IN THE UPPER 40S FOR THE GLACIAL RIDGE. && .MARINE... A WEAK GRADIENT WILL SUPPORT LIGHT WINDS AND CONTINUED TRANQUIL MARINE CONDITIONS TONIGHT THROUGH THE DAY THURSDAY. LOW PRESSURE IS FORECAST TO ADVANCE INTO SRN MI FRIDAY MORNING. THIS WILL LEAD TO A STRENGTHENING NORTHEASTERLY GRADIENT ACROSS LAKE HURON. DETERIORATING BOATING CONDITIONS LATE THURS NIGHT INTO FRIDAY WILL BE A RESULT. THE NORTHEAST WINDS MAY ACTUALLY APPROACH GALE FORCE ON SAGINAW BAY ON FRIDAY. WINDS WILL RELAX FRIDAY NIGHT BEFORE A STRONG COLD FRONT MOVES ACROSS THE REGION ON SATURDAY. THE PASSAGE OF THIS COLD FRONT WILL LEAD TO GUSTY NORTHWEST WINDS FOR THE LATER HALF OF THE WEEKEND. && .AVIATION...ISSUED 101 PM EDT WED MAY 8 2013 //DISCUSSION... A WEAK PRESSURE GRADIENT WILL SUSTAIN LIGHT WINDS THROUGH THE TAF PERIOD. DAYTIME HEATING WILL CONTINUE TO LEAD TO AN ENHANCEMENT IN SOME HIGH BASED CU THIS AFTERNOON. SOME ISOLATED TO SCATTERED SHOWERS ARE POSSIBLE BETWEEN 3 PM AND 7 PM. ANY SHOWER THAT DEVELOPS WILL BE BRIEF WITH CLOUD BASES ABOVE 6K FT COURTESY OF SUBSTANTIAL DRY LOW LEVEL AIR. //DTW THRESHOLD THREATS... * NONE && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....CB MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 081917 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 317 PM EDT SAT JUN 8 2013 .SHORT TERM...THIS EVENING AND TONIGHT THUS FAR THIS AFTERNOON THE CU FIELD HAS BEEN RATHER SHALLOW. A POOL OF COLDER MID LEVEL AIR IS NOW OVERSPREADING NORTHERN AND CENTRAL LOWER MI AS A RESULT OF A COMPACT MID LEVEL SHORT WAVE CURRENTLY OVER NW LOWER MI. THIS COLDER AIR WILL BOOST CONVECTIVE CLOUD DEPTHS ENOUGH TO SUPPORT SOME BRIEF ISOLATED SHOWERS DURING THE REMAINDER OF THE AFTERNOON INTO EARLY EVENING NORTH OF THE M 59 CORRIDOR. THE GREATEST COVERAGE OF SHOWERS IS EXPECTED TO PERSIST ALONG THE HIGHER TERRAIN OF NORTH-CENTRAL LOWER MI...JUST NORTHWEST OF THE TRI CITES. OTHERWISE...CONDITIONS WILL REMAIN RATHER PLEASANT THROUGH EARLY EVENING AS A DECREASING COVERAGE OF THE CLOUDS SHOULD HOLD TEMPS IN THE UPPER 60S/LOWER 70S. THE SHORT WAVE WILL ADVANCE INTO LAKE HURON THIS EVENING. MEANWHILE...ONGOING MID LEVEL TROUGH AMPLIFICATION OVER THE NORTHERN PLAINS WILL BUILD THE DOWNSTREAM RIDGE AXIS OVER THE WRN GREAT LAKES TONIGHT. THE DEEPENING OF LOW PRESSURE OVER THE PLAINS AND RETREAT OF THE SFC HIGH NOW OVER LOWER MI INTO THE EASTERN GREAT LAKES WILL ESTABLISH WEAK LOW LEVEL WARM AIR ADVECTION ACROSS SRN MI OVERNIGHT. THE 12Z NAM SOLUTION ACTUALLY GENERATES SOME LIGHT QPF ALONG/SOUTH OF THE I-96 CORRIDOR OVERNIGHT. THE NAM SUGGESTS A NARROW RIBBON OF GOOD ISENTROPIC ASCENT ALONG THE 300K SURFACE IN THIS REGION DURING THE 9-12Z TIME FRAME. WHILE THIS IS PLAUSIBLE...MODEL SOUNDINGS AND CROSS SECTIONS DEPICT A RATHER STABLE PROFILE ABOVE 700MB. GIVEN THIS AND CONSIDERING THE REMAINDER OF THE 12Z MODEL SUITE ARE MUCH WEAKER WITH THE ISENTROPIC ASCENT...THE FORECAST WILL REMAIN DRY OVERNIGHT INTO EARLY SUN MORNING. PERIODIC CLOUD COVER DURING THE NIGHT AND LOW LEVEL WARM ADVECTION WILL LIMIT THE DEGREE OF RADIATIONAL COOLING AND SUPPORTS MIN TEMPS MAINLY IN THE 50S. && .LONG TERM...SUNDAY THROUGH FRIDAY PROGRESSIVE FLOW WILL ENSURE PERIODS OF CLOUDS, MODERATE TEMPS IN THE 70S, AND OCCASIONAL PRECIP CHANCES THROUGH THE LONG TERM PERIOD. THIS AFTERNOON'S SATELLITE IMAGERY SHOWS THE NEXT SYSTEM FORECAST TO AFFECT SOUTHEAST MICHIGAN IN THE FORM OF A STRONG SHORTWAVE DIGGING INTO THE CENTRAL UNITED STATES. THE EXPANDING CLOUD SHIELD OBSERVED OVER THE NORTHERN PLAINS & UPPER MS VALLEY WILL CONTINUE TO SPILL INTO SOUTHEAST MICHIGAN INTO SUNDAY, WHEN THE ARRIVAL OF BETTER MOISTURE AND FORCING WILL FAVOR A CHANCE FOR SHOWER AND ISOLATED TSTORM DEVELOPMENT BY AFTERNOON. ALTHOUGH SHORTWAVE RIDGING WILL QUICKLY DEVELOP OVER THE CWA IN RESPONSE TO THE DIGGING UPSTREAM WAVE, 300K ISENTROPIC ASCENT BEHIND THE RIDGE AXIS WILL BE SUPPLEMENTED BY A STEADY FEED OF MOISTURE AS PWATS REACH AN INCH DURING PEAK HEATING. AN UNIMPRESSIVE WIND FIELD AND RELATIVELY COOL SE FLOW ACROSS LAKE ERIE DIMINISH ANY SEVERE CONCERNS, BUT BETTER FORCING/INSTABILITY/MOISTURE FROM I-96 SOUTH ARE SUFFICIENT TO WARRANT A HIGH CHANCE POP FOR SUNDAY AFTERNOON ATTM. S/SE FLOW WILL PERSIST ON MONDAY AS THE WAVE CLOSES OFF AND LIFTS TOWARD THE LOWER GREAT LAKES. THE GENERAL LACK OF MESOSCALE FORCING COMBINED WITH LOW DENSITY CAPE PROFILES IN CONJUNCTION WITH MODEST BACKGROUND HEIGHT FALLS AND PWATS AROUND 1.5" OFFER REASON FOR HIGHER CONFIDENCE IN SHOWER/OCCASIONAL TSTORM COVERAGE BY MONDAY. ALTHOUGH CLOUDS AND PRECIP WILL HINDER HIGH TEMPERATURES, THE AREA WILL STILL BE EMBEDDED WELL WITHIN A MUCH WARMER/MORE HUMID AIRMASS BY THIS TIME WHICH SHOULD BE ENOUGH TO SUPPORT TEMPERATURES STILL CLIMBING INTO THE 70S. FOR MIDWEEK, THE ENTRAINMENT OF THE CLOSED LOW OFF THE CA COAST INTO THE PREVAILING WESTERLIES WILL EVOKE A LOW-LEVEL JET RESPONSE THAT WILL MAINTAIN A CONVECTIVE COMPLEX OR TWO ACROSS THE CENTRAL CONUS. THIS WILL PRESENT THE NEXT ORGANIZED OPPORTUNITY FOR RAINFALL, ALTHOUGH THE BULK OF THE ACTIVITY SHOULD REMAIN TIED TO THE INSTABILITY GRADIENT WHICH WILL PRIMARILY RESIDE NEAR/SOUTH OF THE MICHIGAN BORDER. && .MARINE... HIGH PRESSURE WILL SUSTAIN LIGHT WINDS AND CALM WATERS TONIGHT INTO SUNDAY MORNING. EASTERLY WINDS WILL SLOWLY INCREASE SUNDAY AFTERNOON INTO MONDAY AS LOW PRESSURE TRACKS INTO THE SOUTHERN GREAT LAKES REGION. THIS SYSTEM IS FORECAST TO WEAKEN AS IT TRAVERSES THE REGION MONDAY NIGHT...SO WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT. && .AVIATION...ISSUED 101 PM EDT SAT JUN 8 2013 //DISCUSSION... THERE WILL BE A SLOW BUT STEADY LIFTING OF CEILING BASES DURING THE AFTERNOON UNDER PERSISTENT DAYTIME HEATING. THE STRATO CU FIELD SHOULD DISSIPATE DURING THE EVENING WITH THE ONSET OF NIGHTTIME COOLING. THE POTENTIAL FOR LATE DAY SHOWERS LOOKS QUITE LOW...NOT ENOUGH TO JUSTIFY THEM IN THE TAFS. FOR DTW...OBSERVATIONAL TRENDS ALONG WITH THE MOST RECENT MODEL SOUNDINGS WOULD SUGGEST CEILING BASES WITHIN THE STRATO CU FIELD REMAINING PRIMARILY BETWEEN 4K AND 5K FT THROUGH AT LEAST 22Z. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT THROUGH 22Z...LOW CONFIDENCE AFTER 22Z. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....JVC MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 091903 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 303 PM EDT SUN JUN 9 2013 .SHORT TERM...THIS EVENING AND TONIGHT THE UPPER LOW NOW CHURNING OVER WRN IOWA WILL ADVANCE INTO CNTL ILLINOIS OVERNIGHT. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THIS SYSTEM WILL LEAD TO A SIGNIFICANT INCREASE IN LOW AND MID LEVEL MOISTURE ACROSS SOUTHERN MICHIGAN DURING THE COURSE OF THE NIGHT. WEAK MOIST ISENTROPIC ASCENT ALONG THE 300-310K SURFACES WILL SUPPORT INCREASING CHANCES OF RAIN FROM SOUTH TO NORTH BEGINNING AROUND 21Z AND PERSISTING INTO THE OVERNIGHT. THE RAIN CHANCES WILL BE ENHANCED BY SOME WEAKER MID LEVEL IMPULSES NOW APPARENT OVER THE TN/LOWER OH VALLEYS LIFTING INTO FAR SE MI LATE THIS EVENING/EARLY OVERNIGHT. THE MOST RECENT AMDAR SOUNDING OUT OF DTW SHOWS A STRONG MID LEVEL CAPPING INVERSION. THIS IS A RESULT OF A MID LEVEL SHORT WAVE RIDGE AXIS WHICH CURRENTLY IS ALIGNED FROM NE OHIO TO NRN LOWER MI. THE WARM MID LEVEL TEMPS WILL SUPPRESS THE POTENTIAL FOR THUNDERSTORMS THROUGH MOST IF NOT ALL OF THE EVENING...SUGGESTING CONVECTIVE CLOUD DEPTHS WITHIN THE PLUME OF MOISTURE TRAVERSING THE AREA LATER THIS EVENING WILL MOST LIKELY ONLY RESULT IN SOME LIGHT SHOWERS. LARGER SCALE DYNAMIC FORCING WILL THEN OVERSPREAD SRN LOWER MI LATE TONIGHT...SUPPORTING A MARKED INCREASE IN RAINFALL CHANCES. THE FLOW ALOFT WILL BECOME INCREASINGLY DIFFLUENT OVERNIGHT AS THE UPPER LOW ROTATES INTO ILLINOIS. MEANWHILE...MID LEVEL DEFORMATION WILL STRENGTHEN ACROSS THE NRN OHIO VALLEY TONIGHT AND IS FORECAST TO ROTATE INTO METRO DETROIT TOWARD DAYBREAK MONDAY. MODEL SOUNDINGS INDICATE EXCELLENT MOISTURE QUALITY WITHIN THE DEFORMATION REGION AS 700MB DEWPOINTS ARE FORECAST TO RISE TO +4C AND PRECIP WATER APPROACHING 1.8 INCHES. MID LEVEL HEIGHTS WILL FALL ACROSS SE MI OVERNIGHT AS THE RIDGE AXIS LIFTS NORTHEAST AND THE UPPER LOW ROTATES INTO ILLINOIS. THIS WILL SUPPORT AT LEAST SOME WEAK ELEVATED INSTABILITY OVERNIGHT AND THUS BETTER CHANCES FOR THUNDERSTORMS. WHILE THE DEGREE OF MID LEVEL MOISTURE ADVECTION WILL SUPPORT RATHER HIGH POPS OVERNIGHT ACROSS THE TRI CITIES AND THUMB...THE HEAVIEST RAIN SHOULD LINE UP ALONG THE MID LEVEL DEFORMATION AXIS /SOUTH OF THE I-69 CORRIDOR/. THIS SET UP SUPPORTS THE POTENTIAL OF A BAND OF HEAVY RAIN SOMEWHERE ACROSS THE FORECAST AREA...ESPECIALLY IF THE ELEVATED INSTABILITY IS ENOUGH TO CREATE MORE WIDESPREAD AND PROLONGED THUNDERSTORMS. IN LIGHT OF THIS POSSIBILITY...TRENDED OVERNIGHT QPF UPWARDS AND ADDED A CHANCE OF HEAVY RAINFALL TO THE HWO. && .LONG TERM...MONDAY THROUGH SATURDAY THE PERIOD WILL BEGIN WITH SE MICHIGAN ENTRENCHED WITHIN THE MOIST SUBTROPICAL AIRMASS BEING TRANSPORTED ACROSS THE OHIO VALLEY BY A MATURING LOW-LEVEL JET. THE SENSIBLE WX RESPONSE HAS NOT BEEN MUCH TO NOTE JUST YET, BUT WITH THE LLJ FORECAST TO STRENGTHEN TO AROUND 35+KTS UNDER INCREASING LARGE SCALE SUPPORT, SHOWERS AND THUNDERSTORMS ARE FORECAST BLOSSOM WITHIN THE AXIS OF MOISTURE TRANSPORT THAT WILL BE DRAPED ACROSS THE EASTERN HALF OF THE CWA EARLY MONDAY MORNING. BETWEEN 12Z-18Z MONDAY, LOW-LEVEL CONVERGENCE ALONG THE NOSE OF THE MATURED LLJ AND MID-LEVEL H85-H5 DEFORMATION EMBEDDED WITHIN THE NE QUADRANT OF THE UPPER LOW WILL ROTATE ACROSS THE AREA RESULTING IN A SWATH OF MODERATE TO POTENTIALLY HEAVY RAINFALL THROUGH THE MORNING AND EARLY AFTERNOON HOURS. ALTHOUGH MOISTURE TRANSPORT WILL QUICKLY SHIFT EAST FOR THE REMAINDER OF THE DAY AS THE UPPER LOW LIFTS TOWARD THE LOWER GREAT LAKES, LINGERING DEFORMATION WITHIN THE NOW-RESIDENT DEEP/MOIST AIRMASS ALONG WITH A DIURNAL HEATING COMPONENT SHOULD PROVE SUFFICIENT FOR A CONTINUATION OF SHOWERS AND THE OCCASIONAL TSTORM INTO THE EARLY EVENING. IN ADDITION, MARGINAL INSTABILITY LOST BY THE EARLY EXIT OF THE LOW-LEVEL JET WILL BE EFFECTIVELY OFFSET BY THE ENCROACHING COLD POOL ALOFT, ALLOWING SE MICHIGAN TO RESIDE WITHIN A LOW DENSITY CAPE PROFILE FAVORING SHRA WITH EMBEDDED HEAVY RAINFALL FOR THE BALANCE OF THE DAY ON MONDAY. AS A RESULT, AN ADDITIONAL HALF INCH OR SO OF RAINFALL IS FORECAST TO FALL IN ADDITION TO ANYTHING THAT OCCURS PRIOR TO 12Z. RAINFALL COVERAGE AND INTENSITY WILL WIND DOWN MONDAY EVENING INTO MONDAY NIGHT AS DEFORMATION WANES AND DEEPER MOISTURE EXITS THE AREA. LOW-LEVEL JET RESPONSE ELICITED BY THE EJECTION OF THE CLOSED LOW OFF THE CA COAST WILL FOSTER THE DEVELOPMENT OF A THUNDERSTORM COMPLEX OR TWO WEDNESDAY INTO THURSDAY. HOWEVER, PREVAILING NW FLOW COMBINED WITH THE INSTABILITY GRADIENT SETTING UP TO THE SOUTH SHOULD HELP STEER THE BULK OF THIS EXPECTED ACTIVITY AWAY FROM SE MI AND TOWARD THE OHIO VALLEY. TEMPERATURES WILL REMAIN AROUND NORMAL FOR THE TIME OF YEAR. && .MARINE... EASTERLY WINDS HAVE BEEN INCREASING THROUGH THE DAY AS LOW PRESSURE MOVES ACROSS THE MIDWEST AND HIGH PRESSURE DEPARTS TO THE NORTHEAST OF THE GREAT LAKES. THIS EASTERLY WIND REGIME HAS INCREASED THE WINDS AND WAVES OVER LAKE ERIE. THE 240 PM OB FROM THE BUOY OFF THE COAST OF MONROE HAS ENE WINDS GUSTS TO 21 KNOTS WITH WAVES UP TO 3.5 FT. THE EASTERLY WINDS ARE ACTUALLY EXPECTED TO INCREASE THIS EVENING BEFORE DROPPING OFF LATE TONIGHT AS THE BETTER GRADIENT SLIDES TO THE NORTH. THIS SUPPORTS THE SMALL CRAFT ADVISORY FOR THE MICHIGAN WATERS OF LAKE ERIE THROUGH TONIGHT. WHILE THE EASTERLY GRADIENT WILL INCREASE ACROSS LAKE HURON DURING THE NIGHT...COLDER WATER TEMPS WILL MEAN MUCH MORE STABLE CONDITIONS WHICH SHOULD ALLOW ONLY A MODEST INCREASE IN WINDS AND WAVES LATE TONIGHT INTO MON MORNING. WINDS WILL MOST LIKELY PICK UP A LITTLE MORE OVER THE WARMER WATERS OF SAGINAW BAY. THE EASTERLY FETCH SHOULD AT LEAST LIMIT THE WAVE HEIGHTS. WINDS AND WAVES WILL DECREASE LATE MONDAY INTO MONDAY NIGHT AS SURFACE LOW PRESSURE TRACKS ACROSS THE REGION. THE GRADIENT WILL REMAIN LIGHT THROUGH THE REMAINDER OF THE WEEK AND THUS SUPPORTIVE OF LIGHT WINDS. && .AVIATION...ISSUED 107 PM EDT SUN JUN 9 2013 //DISCUSSION... RESIDUAL DRY AIR ASSOCIATED WITH THE SURFACE HIGH PRESSURE ACROSS THE EASTERN GREAT LAKES AND WARM AIR ALOFT WILL SUPPRESS AFTERNOON SHOWERS AND THUNDERSTORMS. THE APPROACH OF THE LOW PRESSURE SYSTEM NOW OVER IOWA WILL LEAD TO DETERIORATING AVIATION CONDITIONS LATE THIS EVENING INTO MON MORNING AS A RESULT OF LOW LEVEL MOISTURE ADVECTION. WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED OVERNIGHT AS THIS LOW PRESSURE SYSTEM NEARS. VERY INTENSE RAIN MAY BE ONGOING FROM THESE SHOWERS AND THUNDERSTORMS THROUGH THE MORNING HOURS ON MONDAY. FOR DTW...WHILE THE EASTERLY WINDS SHOULD SUBSIDE A BIT TOWARD SUNSET...THE GRADIENT IN ADVANCE OF THE APPROACHING LOW PRESSURE SYSTEM IS EXPECTED TO SUSTAIN AN EASTERLY WIND BETWEEN 5 AND 10 KNOTS THROUGH THE NIGHT. WITH THE LOW PRESSURE SYSTEM FORECAST TO MOVE ACROSS METRO ON MONDAY...PERIODIC SHOWERS AND THUNDERSTORMS CAPABLE OF PRODUCING PROLONGED INTENSE RAINFALL ARE POSSIBLE. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT TONIGHT AND MONDAY. * LOW CONFIDENCE IN THUNDERSTORM POTENTIAL THIS EVENING THROUGH MONDAY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE... SMALL CRAFT ADVISORY...UNTIL 4 AM MONDAY. && $$ SHORT TERM...SC LONG TERM....JVC MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 030712 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 312 AM EDT SAT AUG 3 2013 .SHORT TERM...TODAY AND TONIGHT SOLID DECK OF LOW CLOUDS WITH MOISTURE ADVECTION YESTERDAY DURING PEAK HEATING HELD TEMPERATURES IN THE 70S...WHICH FORTUNATELY LIMITED OUR INSTABILITY JUST ENOUGH TO PREVENT ANY SEVERE STORMS FROM DEVELOPING. THE COLD FRONT HAS PRETTY MUCH WASHED OUT...OR IS ILL DEFINED THIS MORNING. DEW POINTS ARE STILL HOVERING AT OR ABOVE 60 DEGREES SOUTH OF I-69 AS OF 2 AM. WATER VAPOR IMAGERY SHOWS GOOD MID LEVEL DRY AIR HAS ARRIVING HOWEVER. A SHEAR OUT SHORTWAVE/UPPER LEVEL PV FILAMENT WILL BE MOVING THROUGH LATER TODAY...AND THE QUESTION IS WHETHER THE SHALLOW SURFACE MOISTURE WILL BE SUFFICIENT TO GENERATE ISOLATED ACTIVITY...AS THERE IS DECENT CAPE IN THE 800 TO 700 MB LAYER AS 850-700 MB LAPSE RATES NOTED TO BE AROUND 7 C/KM. FORTUNATELY EQL LEVELS DO NOT REACH 500 MB LEVEL AS TEMPS FALL TO -14 C WITH THE APPROACHING WAVE. WILL LEAVE THE SHOWER MENTION OUT OF THE FORECAST...AS COVERAGE (IF ANY) SHOULD BE LESS THAN 15 PERCENT. 850 MB TEMPS OF 10 C TO 11 C SUPPORT HIGHS IN THE MID 70S TO AROUND 80 DEGREES WITH SOLID CU UP ANTICIPATED. HIGH PRESSURE BUILDING INTO SOUTHERN LOWER MICHIGAN TONIGHT SHOULD SET US UP FOR A GOOD RADIATING NIGHT...AND USED THE MAV GUIDANCE...PLACING MINS IN THE UPPER 40S TO MID 50S. && .LONG TERM...SUNDAY THROUGH FRIDAY AMPLIFICATION OF THE LONG WAVE TROUGH AXIS WILL BE ONGOING FROM THE ERN GREAT LAKES INTO NEW ENGLAND SUN MORNING WHILE CORRESPONDING HEIGHT RISES ACROSS THE UPPER MIDWEST ALLOW A 1024MB SFC HIGH TO BUILD INTO LOWER MI DURING THE DAY. N-NW LOW LEVEL FLOW IN ADVANCE OF THIS HIGH WILL USHER IN COOLER AIR AS 850MB TEMPS ARE FORECAST TO DROP INTO THE 6-8C RANGE BY 18Z SUN. THERE SHOULD BE A FAIR AMOUNT OF STRATO CU GIVEN THE LOW LEVEL THERMAL TROUGHING AND SOME SEMBLANCE OF MOISTURE FLUX OFF LAKE HURON. MODEL SOUNDINGS SUGGEST CONVECTIVE CLOUD DEPTHS WILL NOT BE QUITE SUFFICIENT ENOUGH TO WARRANT A CHANCE OF SHOWERS AT THIS POINT. THE CLOUDS SHOULD THEN DIMINISH DURING THE LATE AFTERNOON AND EVENING AS THE LOW LEVEL FLOW BECOMES INCREASINGLY ANTICYCLONIC. THE DEGREE OF LOW LEVEL COLD AIR AND POTENTIAL FOR A GOOD DEAL OF CLOUD COVER SUPPORT HIGH TEMPS ONLY IN THE UPPER 60S ACROSS THE THUMB TO LOW 70S ACROSS THE REMAINDER OF SE MI. IN ANTICIPATION OF CLEARING SKIES SUN EVENING AND WITH THE SFC HIGH OVERHEAD...SUN NIGHT MINS MAY DROP INTO THE UPPER 40S/LOW 50S OUTSIDE OF METRO DETROIT. TEMPERATURES WILL THEN SLOWLY MODERATE EARLY NEXT WEEK AS THE SFC HIGH DEPARTS TO THE MID ATLANTIC. PHASING OF ENERGY DROPPING OUT OF NORTHERN CANADA WITH REMNANT LOW PRESSURE OVER HUDSON THIS WEEKEND WILL LEAD TO A DEEP UPPER VORTEX OVER WRN HUDSON BAY BY MONDAY. THE 00Z MODEL SUITE INDICATE THIS VORTEX RETROGRADING INTO MANITOBA EARLY NEXT WEEK. THIS WILL PLACE A FAST UPPER FLOW FROM THE DAKOTAS TO THE GREAT LAKES. NUMEROUS MID LEVEL SHORT WAVE IMPULSES EMBEDDED WITHIN THIS FLOW COUPLED WITH INCREASING MOISTURE AND INSTABILITY ADVECTING INTO LOWER MI AHEAD OF A SFC COLD FRONT WILL SUPPORT A GOOD CHANCE OF CONVECTION DURING THE MID WEEK PERIOD. THE 00Z MODEL SUITE AND A GOOD NUMBER OF THE GFS ENSEMBLE MEMBERS HAVE TRENDED FARTHER WEST AND SLOWER WITH THE UPPER VORTEX. THIS SUGGESTS THE ASSOCIATED COLD FRONT MAY BE DELAYED UNTIL LATE WED OR POSSIBLY THURS. THE SLOWER TREND ALSO SUGGESTS RESIDUAL STABLE AIR ASSOCIATED WITH THE DEPARTING SFC HIGH MAY HOLD ACROSS SE MI THROUGH TUES. THESE TRENDS SUPPORT LOWERING POPS ON TUES AND FOCUSING THE BETTER CHANCE OF CONVECTION IN THE TUES NIGHT TO WED NIGHT TIME FRAME. && .MARINE... NORTHWEST WINDS WILL BE ON THE INCREASE TODAY AND TONIGHT OVER THE CENTRAL GREAT LAKES...AS A COOLER AIRMASS SETTLES OVER THE AREA...CONDUSIVE TO GOOD WAVE GROWTH...WITH WAVES OF 3 TO 6 FEET EXPECTED OVER MUCH OF LAKE HURON ON SUNDAY. SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR TONIGHT THROUGH EARLY SUNDAY EVENING. LIGHTER WIND AND WAVES WILL RETURN SUNDAY NIGHT AND EARLY NEXT WEEK AS HIGH PRESSURE SLIDES THROUGH THE REGION. && .AVIATION...ISSUED 1200 AM EDT SAT AUG 3 2013 //DISCUSSION... THE WEAK COLD FRONT SLIDING THROUGH SE MICHIGAN DURING THE NIGHT WILL EXIT SOUTH OF THE OHIO BORDER BY SUNRISE. ITS PASSAGE WILL BRING AN END TO THE ALREADY MINIMAL CHANCE OF SHOWERS AND THUNDERSTORMS. COOLER AND LESS HUMID AIR WILL FLOW IN BEHIND THE FRONT BUT IT WILL BE SLOW TO ARRIVE IN THE DETROIT AREA. THIS COULD RESULT IN SOME BRIEF/PATCHY MVFR FOG AROUND SUNRISE BEFORE A UNIFORM LIGHT NORTHWEST WIND AND SHALLOW VFR CUMULUS FIELD DEVELOPS OVER ALL OF SE MICHIGAN BY AFTERNOON. THE TEMPERATURE AND MOISTURE PROFILE FAVORS THESE CLOUDS HANGING AROUND DURING SATURDAY EVENING IN THE FORM OF A SCATTERED NEAR ALTOCU WITH LITTLE CONSEQUENCE. //DTW THRESHOLD THREATS... * NONE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....SC MARINE.......SF AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 130739 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 339 AM EDT TUE AUG 13 2013 .SHORT TERM... TODAY AND TONIGHT POST FRONTAL COLD ADVECTION WILL DOMINATE THE WEATHER IN SE MICHIGAN TODAY. ALONG WITH THE IMPACT ON TEMPERATURES, THE MAIN CONSEQUENCE WILL BE A SUBSTANTIAL INSTABILITY INDUCED CLOUD FIELD AND EVEN A FEW LIGHT RAIN SHOWERS DURING THE PEAK OF AFTERNOON SURFACE HEATING. THE NEW 00Z MODEL DATA HAS REASONABLY CAPTURED THE COLD AIR UPSTREAM INDICATED BY UPPER AIR OBSERVATIONS. NORTHERN ONTARIO OBS SITES AT MOOSONEE/CWZC AND PICKLE LAKE/CWPL INDICATE +1C AT 850MB AND -22C AT 500 MB RESPECTIVELY ILLUSTRATING THE MAGNITUDE OF THE COLD AIR. THE MODELS PIVOT THE LOW AND MID LEVEL THERMAL TROUGH OVER LOWER MICHIGAN DURING THE DAY BUT WITH SLIGHTLY LESS MAGNITUDE BY EVENING. STILL, A -18C 500 MB TEMP WOULD BE A RECORD FOR THE DATE WITH 850 MB TEMP NEAR -5C ONLY A COUPLE DEGREES SHY. IT IS NO SURPRISE THAT MODEL SOUNDINGS INDICATE PLENTY OF INSTABILITY IN THE LOW LEVELS WITH ENOUGH MOISTURE TO MAINTAIN CONSIDERABLE CLOUD COVER. IN ADDITION, THERE IS GOOD POSITIVE AREA INDICATED DUE TO ENVIRONMENTAL LAPSE RATE AVERAGING NEAR DRY ADIABATIC FROM CLOUD BASE TO EQL, GOOD ENOUGH TO MAINTAIN THE CHANCE OF SHOWERS IN THE GOING FORECAST AS MAX TEMPS ATTEMPT A RUN AT 70. THE STRONG DIURNAL DEPENDENCY OF THE CLOUDS, ALONG WITH MORE NEUTRAL LOW LEVEL FLOW, WILL RESULT IN A CLEARING TREND DURING THE EVENING. POCKETS OF STRATOCU WILL REMAIN POSSIBLE, ESPECIALLY IN THE THUMB REGION OFF OF LAKE HURON, BUT COVERAGE SHOULD BE LOW ENOUGH FOR MOSTLY CLEAR SKY OVER INTERIOR SECTIONS OF THE AREA. LINGERING GRADIENT WIND WILL PREVENT IDEAL RADIATIONAL COOLING AND MAKES GUIDANCE TEMPS IN THE MID TO UPPER 40S LOOK REASONABLE WITH LOWER 50S IN THE DETROIT METRO AREA. RECORD LOWS FOR WEDNESDAY MORNING ARE: DTW 48/1964, FNT 41/1964, MBS 44/1964. && .LONG TERM...WEDNESDAY THROUGH NEXT MONDAY BROAD AND DEEP LONGWAVE TROUGH WILL CONTINUE TO SIT OVER THE GREAT LAKES THROUGH THE WEEKEND ALTHOUGH IT WILL UNDERGO SOME MODIFICATION. THE STRONG SHORTWAVE OVER SOUTHERN ONTARIO/QUEBEC WILL LIFT NE AWAY FROM SE MI ON WEDNESDAY TAKING WITH IT THE UNSEASONABLY COLD MID LEVEL COLD POOL AND BEST UPPER LEVEL DYNAMICS. WITH THE SHIFT NE...THE NEXT SHORTWAVE TO ROTATE THROUGH THE TROUGH WILL STAY OVER CANADA AVOIDING SOUTHERN MI FOR THE FIRST TIME IN A WHILE. AS A RESULT OF THE SHORTWAVE LIFTING OUT OF THE AREA...HEIGHTS WILL SLOWLY RISE THROUGH THE WEEK. ALTHOUGH THE PATTERN WOULD SUGGEST THE AMPLIFIED WEST COAST RIDGE WOULD SLIDE EAST BEHIND THE DEPARTING WAVE...A WEAK SHORTWAVE DIVING INTO THE BASE OF THE TROUGH LOOKS TO DEVELOP A CUTOFF LOW OVER THE MID MISSISSIPPI VALLEY FRIDAY. WITH THE FLOW OVER THE CONUS NEGLIGIBLE (LONGWAVE PATTERN TRENDING ZONAL ACROSS CANADA) AND THE BERMUDA HIGH HOLDING FIRM OFF THE EAST COAST...THIS LOW WILL EVER SO SLOWLY DRIFT THROUGH THE OHIO VALLEY. DOWN AT THE SFC...HIGH PRESSURE WILL DROP OVER THE GREAT LAKES FROM CANADA AND WILL PERSIST THROUGHOUT THE EXTENDED PERIOD. INITIALLY ON WEDNESDAY WE WILL BE ON THE EASTERN PERIPHERY WHICH WILL PRODUCE N/NW FLOW OVER THE AREA. WITH THE MID LEVEL COLD POOL STILL OVER THE EASTERN GREAT LAKES AND 850 MB TEMPS IN THE MID SINGLE DIGITS...LOOK FOR ANOTHER CHILLY DAY WITH TEMPS STRUGGLING TO TOUCH 70 FOR MOST LOCATIONS. IN ADDITION...THE COLD AIR AND FAVORABLE FETCH WILL LEAD TO A SLIGHT CHANCE OF PRECIP OVER LAKE HURON DUE TO THE RELATIVELY WARM WATER. THE NW FLOW SHOULD KEEP THE RAIN OFF SHORE BUT MAY INITIALLY COME CLOSE TO THE EASTERN THUMB. THAT IS THE MOST EXCITEMENT WE WILL DEAL WITH FOR THE NEXT SEVERAL DAYS. THE SFC HIGH WILL DRIFT OVER MI AND THEN TO THE EAST THROUGH THE WEEKEND. WITH 1000-500MB HEIGHTS ON THE RISE AND A DRY AIRMASS...LOOK FOR MOSTLY CLEAR/SUNNY SKIES AND A GRADUAL WARMING TREND. BY THE END OF THE WEEKEND OR EARLY NEXT WEEK...WE WILL FALL UNDER THE WESTERN EDGE OF THE HIGH WHICH WILL LEAD TO SOUTHWESTERLY FLOW AND WAA. THIS SHOULD BRING US BACK TO NORMAL FOR TEMPS TO START THE NEXT WEEK. && .MARINE... SMALL CRAFT ADVISORIES REMAIN IN EFFECT TODAY AND TONIGHT AS COOL NORTHERLY WIND OF MODERATE INTENSITY WILL PRODUCE ROUGH MARINE CONDITIONS, ESPECIALLY OVER THE SOUTH HALF OF LAKE HURON. IN ADDITION TO GUSTY WIND AND HIGH WAVES, THE COOL AIR FLOWING OVER THE WARM WATER WILL INCREASE POTENTIAL FOR WATERSPOUT FORMATION. MODEL SOUNDINGS OVER THE OPEN WATERS OF SOUTHERN LAKE HURON INDICATE STRONG CLOUD BASE ACCELERATION WITH LAKE TO 850 MB DELTA-T AROUND 15C AND CLOUD DEPTH OF AROUND 7500 FEET. THESE ARE ENTRY LEVEL PARAMETERS THAT SUGGEST POTENTIAL WORTHY OF A CHANCE MENTION IN THE FORECAST MAINLY FOR TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD MORE FULLY OVER THE LAKES BY WEDNESDAY WITH LIGHTER WIND AND IMPROVED WAVE CONDITIONS THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. && .AVIATION...ISSUED 1203 AM EDT TUE AUG 13 2013 //DISCUSSION... WITH SHRAS/TSRAS SHIFTING SOUTHEAST OF THE AREA...ATTENTION TURNS TO MVFR STRATUS AND/OR FOG OVERNIGHT IN WAKE OF PASSING COLD FRONT. LATEST OBS INDICATE PATCHY DEVELOPMENT JUST PRIOR TO THE FRONTAL PASSAGE. WILL ADJUST 06Z TERMINALS AS SUCH...WITH GENERALLY VFR CONDITIONS LATER AND JUST A TEMPO PERIOD FOR ANY PATCHY LOW CEILINGS. HIGH PRESSURE WILL BRING GRADUALLY CLEARING SKIES LATER TODAY WITH CIGS INITIALLY LIFTING AND THEN CLEARING OUT ALTOGETHER BY THE END OF THE FORECAST PERIOD. FOR DTW...THERE STILL MAY BE A PERIOD OF SUB 4000 FOOT CIGS LATE TONIGHT THROUGH THE MORNING WITH PATCHY FOG AS WELL...BUT TRENDS SUGGEST ANY LOWER CIGS IN THE WAKE OF THE COLD FRONT WILL BE SHORT LIVED. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 4 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....DRK MARINE.......BT AVIATION.....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 131935 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 335 PM EDT TUE AUG 13 2013 .SHORT TERM... TONIGHT SURFACE DEW POINTS HAVE DROPPED INTO THE 40S OVER SOUTHERN LOWER MICHIGAN...AS 850-700 MB THETA-E MINIMUM/TROUGH SWINGS INTO SOUTHEAST MICHIGAN LATE THIS AFTERNOON/EARLY THIS EVENING. THIS AMOUNT OF DRY AIR HAS LIMITED THE VERTICAL EXTENT OF THE CU FIELD...AND CHANCES FOR MEASURABLE SHOWERS APPEARS LOW (SLIGHT CHANCE...BETTER CHANCE FOR SPRINKLES). SEE NO COMPELLING REASON WHY DIURNAL ENHANCED CU FIELD WILL NOT DIMINISH THIS EVENING....AS LOW LEVEL FLOW REMAINS OUT OF THE NORTHWEST...KEEPING ANY LAKE HURON CLOUDS CONFINED TO FAR EASTERN THUMB REGION. WITH THE CLEARING SKIES AND DEW PTS IN THE LOW TO MID 40S...SEEMS LIKE A GOOD BET MINS WILL DROP OFF INTO THE 40S. HOWEVER...THINK THE RECORD LOWS WILL BE DIFFICULT TO ACHIEVE...AS A LIGHT WIND IS EXPECTED TO PERSIST WITH THE CENTER OF THE HIGH STILL A BIT TO FAR TO THE WEST (MIDWEST) AT 12Z WEDNESDAY FOR WINDS TO FULLY DECOUPLE...AND WILL SKEW THE MINS IN THE MID TO UPPER 40S DIRECTION....WITH LOWER 50S FOR URBAN HEAT ISLAND OF DETROIT. RECORD LOWS FOR WEDNESDAY MORNING (AUGUST 14TH): DTW 48/1964. FNT 41/1964. MBS 44/1964. && .LONG TERM...WEDNESDAY THROUGH NEXT TUESDAY QUIET WEATHER IS IN STORE FOR MOST OF THE GREAT LAKES REGION INCLUDING SOUTHEAST MICHIGAN THROUGH THE END OF THE WEEK AS A WELL AMPLIFIED RIDGE REMAINS TO OUR WEST OVER THE ROCKIES. THIS PATTERN WILL RESULT IN SURFACE HIGH PRESSURE TO HOVER OVER THE GREAT LAKES REGION. NORTHWEST WINDS WILL DEVELOP ON WEDNESDAY AND LAST THROUGH THURSDAY BRINGING COOLER TEMPERATURES TO SOUTHEAST MICHIGAN. HIGH TEMPERATURES ON WEDNESDAY ARE ONLY EXPECTED TO REACH INTO THE LOW 70S IN METRO DETROIT...WITH MANY OF THE SURROUNDING AREAS NOT MAKING IT OUT OF THE UPPER 60S. THURSDAY AND THURSDAY NIGHT TEMPERATURES WILL BE SLIGHTLY WARMER ALLOWING MOST SITES TO GET AT LEAST INTO THE LOWER 70S. WINDS WILL DIMINISH SLIGHTLY ON FRIDAY...ALLOWING THE SURFACE TEMPERATURES TO BEGIN TO HEAT UP BY THE END OF THE WEEK. HOWEVER...850 MB TEMPERATURES REMAIN BELOW 8 C THROUGH FRIDAY KEEPING SURFACE TEMPERATURES WELL BELOW NORMAL FOR THROUGH THE WEEKEND. THE ONLY CHANCE OF A POSSIBLE RAIN SHOWER WILL BE MAINLY ACROSS THE NORTHERN SUBURBS INTO THE THUMB AND SAGINAW VALLEY REGIONS ON FRIDAY AND FRIDAY NIGHT AS A WEAK SHORTWAVE TROUGH SLIDES OVER MICHIGAN. HAVE BUMPED UP POPS DURING THIS TIMEFRAME TO ACCOUNT FOR THE SLIGHT CHANCE. OTHERWISE...HIGH PRESSURE WILL STICK AROUND THROUGH EARLY NEXT WEEK BEFORE SLOWLY SLIDING EASTWARD ALLOWING DRY CONDITIONS AND CLEAR TO PARTLY CLOUDY SKIES TO REMAIN THROUGH MOST OF THE EXTENDED PERIOD. TEMPERATURES FINALLY BEGIN TO INCREASE /HIGHS REACHING INTO THE 80S/ BY EARLY NEXT WEEK AS WINDS SHIFT TO THE SOUTHEAST ALLOWING WARM AIR ADVECTION TO TAKE PLACE. HIGH PRESSURE WILL STILL BE IN PLACE THOUGH...KEEPING US DRY. THE NEXT SIGNIFICANT CHANCE OF PRECIPITATION WILL OCCUR ON TUESDAY AND TUESDAY NIGHT AS THE NEXT LOW PRESSURE SYSTEM APPROACHES THE REGION. HOWEVER...CONFIDENCE IS LOW WITH THE TIMING AND INTENSITY AS THIS SYSTEM IS STILL ABOUT A WEEK AWAY. CONFIDENCE SHOULD INCREASE OVER THE NEXT FEW DAYS AS THE ENERGY ASSOCIATED WITH THIS SYSTEM BEGINS TO BE SAMPLED AND THE FEATURE BECOMES BETTER DEFINED. && .MARINE... NORTHWEST WINDS HAVE HAD NO PROBLEM GUSTING TO AROUND 20 KNOTS ALONG THE NEARSHORE WATERS OF LAKE HURON THIS AFTERNOON...WITH GUSTS TO AROUND 30 KNOTS OVER THE OPEN WATERS...AS COOL CANADIAN AIRMASS ADVECTS INTO THE CENTRAL GREAT LAKES REGION. IN ADDITION TO GUSTY WIND AND HIGH WAVES...THE COOL AIR FLOWING OVER THE WARM WATER WILL INCREASE POTENTIAL FOR WATERSPOUT FORMATION. MODEL SOUNDINGS OVER THE OPEN WATERS OF SOUTHERN LAKE HURON INDICATE STRONG CLOUD BASE ACCELERATION WITH LAKE TO 850 MB DELTA-T AROUND 15C AND CLOUD DEPTH OF AROUND 7500 FEET EARLY THIS EVENING. THESE ARE ENTRY LEVEL PARAMETERS THAT SUGGEST POTENTIAL WORTHY OF A CHANCE MENTION IN THE FORECAST THROUGH TONIGHT. SURFACE HIGH PRESSURE WILL THEN BUILD MORE FULLY OVER THE LAKES BY WEDNESDAY WITH LIGHTER WIND AND IMPROVED WAVE CONDITIONS THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. && .AVIATION...ISSUED 1246 PM EDT TUE AUG 13 2013 //DISCUSSION... COOLER AND DRIER AIR CONTINUES TO MAKE INROADS INTO SOUTHERN LOWER MICHIGAN...AS SURFACE DEW PTS HAVE FALLEN INTO THE 40S ACROSS MOST LOCATIONS. THIS DRIER AIR WILL SUPPORT JUST BROKEN LOW VFR CLOUD DECK THIS AFTERNOON. LOSS OF DAYTIME HEATING IS EXPECTED TO LEAD TO CLEARING SKIES THIS EVENING. GUSTY NORTHWEST WINDS TO AROUND 20 KNOTS THIS AFTERNOON WILL SETTLE DOWN TONIGHT...BUT A LIGHT WIND WILL PROBABLY PERSIST AS HIGH PRESSURE FAILS TO FULLY BUILD INTO SOUTHEAST MICHIGAN BY SUNRISE. ANOTHER ROUND OF LOW CU DEVELOPMENT EXPECTED TOMORROW...BUT PROBABLY NOT AS WIDESPREAD (SCT CLOUDS). //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT THIS AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 4 PM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....RK MARINE.......SF AVIATION.....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 140742 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 342 AM EDT WED AUG 14 2013 .SHORT TERM... TODAY AND TONIGHT ANOTHER COOL DAY IS IN STORE FOR SE MICHIGAN AS CANADIAN HIGH PRESSURE SETTLES OVER THE REGION. STRONG COLD ADVECTION YESTERDAY, ALONG WITH A BROKEN CLOUD LAYER, MADE IT A STRUGGLE FOR TEMPERATURES TO REACH 70. TODAY, COLD ADVECTION WILL BE WEAKER DURING THE MORNING AND BECOME NEUTRAL DURING THE AFTERNOON. THERE WILL ALSO BE A GREATER AMOUNT OF DRY AIR IN THE BOUNDARY LAYER WHICH WILL RESULT IN MORE OF A GENEROUS SCATTERED COVERAGE OF CLOUDS RATHER THAN BROKEN TO OVERCAST. THE RESULT WILL BE A MODEST REBOUND IN MAX TEMPS TODAY WITH MOST LOCATIONS HITTING 70 WHILE A FEW OF THE TYPICALLY COOLER LOCATIONS IN THE THUMB SETTLE FOR UPPER 60S. TONIGHT THE SURFACE HIGH WILL QUICKLY BECOME CENTERED SOUTH OF THE OHIO BORDER WHICH WILL ALLOW THE WIND TO BECOME CALM OVER THE REGION. THIS, ALONG WITH DECREASING CLOUDS, WILL SET UP IDEAL RADIATIONAL COOLING CONDITIONS AND ANOTHER RUN AT RECORD LOWS. THERE WILL BE A TENDENCY FOR THE FLOW TO BACK TOWARD THE WEST IN THE 925-850 MB LAYER, WHICH THE 00Z MODELS SUGGEST THE POTENTIAL FOR LAKE MICHIGAN STRATOCU WILL BECOME A CONSIDERATION. AT THIS POINT, THE TIMING LOOKS TOO SLOW FOR CLOUDS TO MAKE A DIFFERENCE IN THE MIN TEMP FORECAST FAVORING THE COOLER MID TO UPPER 40S GUIDANCE OFFERINGS. RECORD LOWS FOR THURSDAY MORNING (AUGUST 15TH): DTW 46/1979. FNT 42/1964. MBS 43/2004. && .LONG TERM...THURSDAY THROUGH NEXT TUESDAY THE EXTENDED FORECAST IS A QUITE ONE AS WE WATCH THE AMPLIFIED LONGWAVE PATTERN (WEST COAST RIDGE AND EASTERN CONUS TROUGH) SLOWLY BREAK DOWN AND TRANSITION TO A MORE ZONAL PATTERN. THE LOWEST HEIGHTS WITHIN THE TROUGH HAVE ALREADY PULLED AWAY TO THE NE WHICH IN ITSELF IS LENDING TO A SLIGHT INCREASE IN HEIGHTS. AS THE TROUGH FILLS IN AND THE FLOW BECOMES ZONAL ACROSS SOUTHERN CANADA...THE MODELS WANT TO PINCH OFF A CLOSED LOW OVER THE MID MISSISSIPPI VALLEY. WITH VERY LITTLE STEERING FLOW OVER THE CENTRAL CONUS AND A REGION OF HIGH PRESSURE SLIDING WEST ACROSS BERMUDA TOWARD FL AND THE GOM...THIS REGION OF LOWER HEIGHTS WOULD MERELY DRIFT EASTWARD ALONG THE SOUTHERN OHIO VALLEY. DOWN AT THE SFC...HIGH PRESSURE WILL BE SPREAD ACROSS THE MIDWEST...GREAT LAKES...AND THE EAST COAST. DRY AIR WILL PERSIST OVER THE AREA WITHIN THE HIGH THROUGH THE WEEKEND. BELOW ABOUT 800 MB RH VALUES WILL REACH AROUND 50 PERCENT IN THE AFTERNOON BUT ABOUT 800 MB LOOKS TO STAY BELOW 30 PERCENT. THIS WILL MAKE IT HARD FOR ANY WEAK SHORTWAVES THAT TRY TO BRUSH THE REGION TO AMOUNT TO ANYTHING MORE THEN A BRIEF UPTICK IN CLOUDS...MOSTLY DURING PEAK HEATING. AS THE HIGH SLIDES EASTWARD THE LL FLOW WILL TURN WESTERLY OVER THE WEEKEND AND THEN SOUTHWESTERLY FOR THE BEGINNING OF NEXT WEEK. THE COMBINATION OF THE INCREASING HEIGHTS AND WEAK WAA WILL LEAD TO A MODERATING AIRMASS WITH TEMPERATURES CLIMBING BACK TOWARD NORMAL BY THE END OF THE WEEKEND. THOUGH IT IS A WAYS OUT THERE...IT SHOULD BE MENTIONED THAT THE NEXT CHANCE FOR ANY PRECIP WILL COME AROUND TUESDAY WHEN MODELS SUGGEST A SHORTWAVE WILL TRACK THROUGH THE REGION. 24 HOURS AGO BOTH THE GFS AND ECMWF WERE MUCH MORE BULLISH WITH THE SHORTWAVE AND RESULTING PRECIP BUT HAVE BOTH TRENDED DOWNWARD IN THE LATEST RUNS. BOTH MODELS ALSO INDICATE THE DEVELOPING TROPICAL SYSTEM OVER THE CARIBBEAN SEA WILL TRACK NORTHWARD AND GET ABSORBED BY THE TROUGH AND LIFT UP THE EAST COAST. WE WILL HAVE TO MONITOR THE CUTOFF LOW AND TROUGH POSITIONING TO MAKE SURE THIS ENHANCED AREA OF MOISTURE STAYS TO THE SE AS IT IS CURRENTLY ADVERTISED. && .MARINE... SMALL CRAFT ADVISORIES REMAIN IN EFFECT TODAY FOR OUTER SAGINAW BAY AND THE NEARSHORE WATERS OF SOUTHERN LAKE HURON DUE TO CONTINUING GUSTY WIND AND HIGH WAVES. THERE IS ALSO A LINGERING CHANCE OF WATERSPOUTS AS COOL AIR FLOWS OVER THE WARM LAKE WATER, ALTHOUGH CONDITIONS WILL BECOME LESS FAVORABLE MAINLY DUE TO DRY AIR IN THE LOW LEVELS REDUCING CLOUD DEPTH AND INSTABILITY WITHIN THE CLOUD LAYER. PEAK WIND GUSTS TO 30 KNOTS WILL REMAIN POSSIBLE OVER THE OPEN WATERS THROUGH ABOUT MID MORNING BEFORE HIGH PRESSURE BUILDS IN ENOUGH FOR A NOTICEABLE DIMINISHING TREND IN WIND SPEED FOR THE REST OF THE DAY. THAT WILL ALLOW HIGH WAVES TO SUBSIDE BY EVENING WHICH WILL MARK THE BEGINNING OF A LONG STRETCH OF FAVORABLE MARINE CONDITIONS THROUGH THE WEEKEND. HIGH PRESSURE WILL BECOME CENTERED OVER LAKE ERIE DURING THE END OF THE WEEK AND THEN DRIFT BACK OVER LAKE HURON AND LOWER MICHIGAN DURING THE WEEKEND. && .AVIATION...ISSUED 1202 AM EDT WED AUG 14 2013 //DISCUSSION... VFR CONDITIONS THROUGH THE PERIOD AS CONSIDERABLE DRYING CONTINUES WITHIN THE LOWER LEVELS. OCCASIONAL POCKETS OF HIGHER BASED CLOUD COVER /6-7K FT/ WILL CONTINUE TO DRIFT THROUGH AT TIMES THIS MORNING AS THE WESTERN EXTENSION OF A MID LEVEL TROUGH WORKS ACROSS THE REGION. LIGHT NORTHWEST FLOW HOLDS ON WEDNESDAY AS HIGH PRESSURE TAKES CONTROL. ANOTHER ROUND OF SCT DIURNAL CU FOR THE MIDDAY PERIOD. //DTW THRESHOLD THREATS... * NONE && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 4 PM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....DRK MARINE.......BT AVIATION.....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 120642 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 242 AM EDT THU SEP 12 2013 .SHORT TERM...TODAY AND TONIGHT A SECONDARY COLD FRONT NOW LOCATED OVER NW LOWER MI WILL ADVANCE ACROSS SE MI BETWEEN 09Z AND 15Z THIS MORNING. THE FRONT SHOULD SLOW CONSIDERABLY AS IT APPROACHES THE OHIO BORDER LATER THIS MORNING AS IT ALIGNS MORE OR LESS PARALLEL TO THE MID LEVEL FLOW. A NARROW RIBBON OF MID LEVEL MOISTURE ALONG/IN ADVANCE OF THIS FRONT WILL POSE THE RISK OF SOME ISOLATED CONVECTION THIS MORNING...WITH A LITTLE BETTER CHANCE SOUTH OF METRO DETROIT WHERE INSTABILITY WILL BE HIGHER. POST FRONTAL COLD AIR ADVECTION WILL BE ONGOING THROUGH THE DAY. THE LOW LEVEL COOLING WILL BE OFFSET A BIT BY STEEPENING LOW LEVEL LAPSE RATES UNDER DIURNAL HEATING. NONETHELESS...TEMPS WILL BE A GOOD DEAL COOLER THAN THE PAST COUPLE OF DAYS AS MOST LOCALS SEE HIGHS IN THE MID/UPPER 70S. MORE NOTICEABLE WILL BE A PUSH OF MUCH DRIER AIR FROM THE NORTHWEST DURING THE AFTERNOON...LEADING TO A SIGNIFICANT DROP IN SFC DEWPOINTS. A MID LEVEL SHORT WAVE NOW DROPPING ACROSS MN WILL RACE ACROSS THE NRN OHIO VALLEY EARLY THIS AFTERNOON...WHILE A SECONDARY MID LEVEL WAVE NOW OVER MANITOBA DIVES INTO LOWER MI LATE THIS AFTERNOON AND EVENING...LEADING TO SUBSTANTIAL MID LEVEL HEIGHT FALLS ACROSS THE STATE. GOOD DCVA AND DIVERGENCE WITHIN THE EXIT REGION OF A CYCLONICALLY CURVED UPPER JET STREAK WILL LEAD TO VERY GOOD DYNAMIC FORCING LATE THIS AFTERNOON AND EVENING. MOISTURE QUALITY WILL BE THE MAIN FACTOR LIMITING OVERALL PRECIP CHANCES. NONETHELESS...MODEL SOUNDINGS DO SHOW SOME SEMBLANCE OF MID LEVEL MOISTURE NEAR AND ATOP THE MIXED LAYER WHICH WILL SUPPORT AT LEAST SOME SCATTERED LIGHT SHOWERS LATE THIS AFTERNOON AND EVENING. DESPITE COOLING TEMPS ALOFT...THE LOW LEVEL DRY AIR ADVECTION IS SHOWN TO SIGNIFICANTLY LIMIT CONVECTIVE CLOUD DEPTH. THIS SUPPORTS HOLDING OFF ON THE MENTION OF ANY THUNDER THIS AFTERNOON AT THIS TIME. CONTINUED AMPLIFICATION OF THE LONG WAVE TOUGH ROTATING EAST OF LOWER MI TONIGHT WILL SEND YET ANOTHER COLD FRONT ACROSS THE REGION OVERNIGHT. THIS FRONT WILL ACTUALLY BE DRIVEN INTO SE MI FROM LAKE HURON AND WILL ADVECT AN AIRMASS ORIGINATING FROM HUDSON BAY...WITH 850MB TEMPS FORECAST TO DROP TO 0C OVER CENTRAL MI BY 12Z FRI. LAKE MODIFIED SOUNDINGS SUGGEST EQUILIBRIUM LEVELS RISING ABOVE 10K FT OVER SRN LAKE HURON OVERNIGHT. THIS AND SOME LINGERING MID LEVEL MOISTURE OVER THE LAKE WILL PROVIDE A GOOD SET UP FOR LAKE EFFECT RAIN SHOWERS. AS THE LOW LEVEL FLOW TURNS NORTHERLY OVERNIGHT...THESE SHOWERS WILL OVERSPREAD MUCH OF THE THUMB REGION. GIVEN THE STRONGER GRADIENT...WOULD NOT BE SURPRISED IF A FEW OF THESE SHOWERS MADE THEIR WAY INTO THE NRN DETROIT SUBURBS. && .LONG TERM... THE PERIOD WILL BEGIN WITH SPRAWLING CANADIAN HIGH PRESSURE BUILDING INTO SOUTHEAST MICHIGAN BENEATH A RECOVERING HEIGHT FIELD ALOFT. ONGOING COLD ADVECTION WITHIN THE NORTHERLY GRADIENT AROUND THE HIGH WILL SUSTAIN AN ABUNDANCE OF STRATUS THROUGH AT LEAST THE FIRST HALF OF THE DAY ON FRIDAY. THIS WILL PARTICULARLY BE THE CASE DOWNWIND OF LAKE HURON WHERE BOUNDARY LAYER THETA-E FLUX WILL BE PLENTIFUL GIVEN H85 TEMPS FALLING INTO THE -2C TO 1C RANGE. REGARDLESS, ALL LOCATIONS WILL EFFECTIVELY CLOUD UP ONCE DIURNAL DEEPENING OF THE BOUNDARY LAYER GETS UNDERWAY BY LATE MORNING/EARLY AFTN. LAKE EFFECT SHOWERS WILL BE ONGOING DURING THIS PERIOD AS WELL AS THE AXIS OF DEEPER MOISTURE PIVOTS ACROSS THE THUMB DURING THE MORNING. HAVE UPPED POPS ACCORDINGLY ACROSS FAR EASTERN AREAS PRIOR TO 18Z. FORECAST HIGHS RANGING FROM THE MID 50S TO LOW 60S REMAIN IN LINE WITH EXPECTATIONS FOR FRIDAY AFTERNOON. THE COLDEST READINGS ARE SURE TO BE FOUND ACROSS THE THUMB WHERE LAKE HURON WILL PROVIDE LOCAL ENHANCEMENT OF SYNOPTIC SCALE COLD ADVECTION. AN ADJUSTMENT IN TEMPERATURES EITHER UP OR DOWN REMAINS POSSIBLE, HOWEVER, DEPENDING ON THE DURATION OF AFOREMENTIONED CLOUD COVER. DESPITE MODEL RH FIELDS INDICATING A RAPID CLEARING TREND AS ANTICYCLONIC FLOW AGGRESSIVELY BUILDS INTO THE AREA BY LATER IN THE DAY, FORECAST SOUNDINGS DO NOT INSPIRE MUCH HIGH CONFIDENCE. A SCENARIO IN WHICH CLOUDS HANG ON INTO THE LATE EVENING IS EASILY PLAUSIBLE AND THE FORECAST REFLECTS THIS POSSIBILITY WITH A SLIGHTLY MORE PESSIMISTIC CLEARING TREND IN THE 18Z-00Z WINDOW AND A SLIGHT DOWNWARD ADJUSTMENT IN MAX TEMPS. CLEARING SKIES WILL THEN ALLOW FOR EARLY DECOUPLING ON FRIDAY NIGHT AS CANADIAN HIGH PRESSURE SETTLES OVER CENTRAL LOWER. THE LATEST GUIDANCE SUPPORTS THE INHERITED FORECAST WHICH CALLS FOR LOWS FALLING INTO THE 30S AWAY FROM THE DETROIT METRO HEAT ISLAND AND POTENTIALLY INTO FROST TERRITORY FOR THE SAGINAW VALLEY AREA BY SATURDAY MORNING. SATURDAY WILL FEATURE A HEALTHY TEMPERATURE RECOVERY FROM COLD MORNING READINGS AS WARMER TEMPERATURES MOVE IN ALOFT BENEATH THE PASSING SHORTWAVE RIDGE AXIS AND MID-SEPTEMBER INSOLATION ALLOWS FOR LOCAL MODERATION OF THE RESIDENT AIRMASS. AS A RESULT, AFTERNOON HIGHS IN THE MID 60S UNDER FULL OR NEARLY FULL SUN SHOULD BE EASY TO ACHIEVE. TROUGHING WILL THEN RECHARGE OVER THE GREAT LAKES TOWARD THE END OF THE WEEKEND AS A TROUGH ANCHORED BY THE LOW CURRENTLY OVER THE NW TERRITORIES AMPLIFIES COURTESY OF AN INFLUX OF UPPER ENERGY ORIGINATING OVER THE NORTH PACIFIC. A BRIEF BOUT OF WARM ADVECTION AHEAD OF THE FRONT WILL SUPPORT HIGHS FURTHER REBOUNDING TOWARD SEASONAL NORMALS BY SUNDAY FOLLOWED BY A CHANCE OF RAIN AND A RETURN TO LOW/MID 60S BY MONDAY. && .MARINE... WINDS WILL TURN TO THE NORTHWEST TODAY WITH THE PASSAGE OF A COLD FRONT AND WILL INCREASE STEADILY HEADING INTO THE AFTERNOON UNDER PERSISTENT LOW LEVEL COLD AIR ADVECTION. A SECONDARY COLD FRONT WILL MOVE ACROSS LAKE HURON TONIGHT...WITH SIGNIFICANTLY COLDER AIR FILTERING BEHIND IT. THE GRADIENT UNDER THIS COLD AIR ADVECTION WILL SUPPORT WIND GUSTS UP TO 30 KNOTS LATE TONIGHT INTO FRIDAY. WINDS AND WAVES WILL BE HIGHEST ACROSS THE SOUTHERN HALF OF LAKE HURON GIVEN THE NORTHERLY WIND DIRECTION. WINDS AND WAVES WILL DECREASE SUBSTANTIALLY FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE OVERSPREADS THE REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE REGION ON SUNDAY. SOUTHWEST WINDS WILL INCREASE SATURDAY NIGHT IN ADVANCE OF THIS FRONT...WITH GUSTY N-NW WINDS ROLLING IN LATE SUN/SUN NIGHT IN THE WAKE OF THE FRONT. && .AVIATION...ISSUED 1202 AM EDT THU SEP 12 2013 //DISCUSSION... WHILE THE INITIAL COLD FRONT RESPONSIBLE FOR LAST EVENINGS CONVECTION HAS MOVED WELL SOUTHEAST OF DETROIT...A SECONDARY COLD FRONT IS NOW ADVANCING INTO NW LOWER MI. THIS FRONT IS FORECAST TO TRACK ACROSS SE MI BETWEEN 09Z AND 12Z. THERE HAS BEEN SOME SCATTERED CONVECTION ACROSS NRN LOWER MI IN ADVANCE OF THIS FRONT. WHILE THERE IS A CHANCE OF SHOWERS OR A BRIEF THUNDERSTORM EARLY THIS MORNING IN ADVANCE OF THIS FRONT...THE LACK OF SUFFICIENT INSTABILITY WILL KEEP CHANCES QUITE LOW AND NOT HIGH ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. RELATIVELY HIGH AMBIENT MOISTURE IN THE PRE FRONTAL AIRMASS AND SOME INTERVALS OF CLEAR SKIES WILL PROVIDE SOME CHANCES FOR MVFR TYPE VSBY IN FOG PRIOR TO THE PASSAGE OF THE COLD FRONT. DRIER AIR WILL FILTER INTO THE AREA FOLLOWING FROPA UNDER STRENGTHENING NORTHWEST WINDS. //DTW THRESHOLD THREATS... * LOW CONFIDENCE CEILINGS WILL FALL BELOW 5000 FT THIS MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...FROM 4 PM THURSDAY TO 2 AM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....JVC MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 211449 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1049 AM EDT SAT SEP 21 2013 .UPDATE... THE REGION OF -SHRA WHICH HAVE BEEN SLOWLY ADVANCING ACROSS THE NORTHERN HALF OF THE FORECAST AREA DEVELOPED ALONG THE LEADING EDGE OF A MID LEVEL CIRCULATION EMBEDDED WITHIN THE BASE OF THE LONG WAVE TROUGH NOW PUSHING ACROSS LOWER MI. THIS FEATURE WILL SLOWLY ADVANCE TO THE EAST THROUGH THE EARLY AFTERNOON. MID LEVEL SUBSIDENCE IN THE WAKE OF THIS IMPULSE WILL REDUCE THE CONVECTIVE CLOUD DEPTHS AND WILL DRAMATICALLY DECREASE THE INTENSITY AND COVERAGE OF ANY LINGERING SHOWERS. AVAILABLE OBSERVATIONS ACROSS SRN LAKE HURON SUGGEST SOME ENHANCED CONVERGENCE ALONG THE EASTERN SHORE OF THE THUMB WHICH MAY ALLOW SOME SHOWERS TO LINGER ALONG A LINE FROM PORT SANILAC TO PORT HURON MUCH LATER INTO THE AFTERNOON. WHILE THERE HAVE BEEN SOME BREAKS IN THE CLOUDS THIS MORNING...ONGOING LOW LEVEL COLD AIR ADVECTION...A DEEPENING SUBSIDENCE INVERSION AND MOISTURE FLUX OFF THE GREAT LAKES SUGGEST A FAIRLY CLOUDY AFTERNOON. TEMPS THIS MORNING HAVE BEEN RUNNING A BIT BELOW GUIDANCE. THE DEGREE WARMING IN THE BOUNDARY LAYER SHOWN IN MODEL FORECAST SOUNDINGS THIS AFTERNOON SEEMS A BIT SUSPECT CONSIDERING THE EXPECTED CLOUD COVER AND ONGOING COLD AIR ADVECTION. A FORECAST UPDATE WILL BE ISSUED TO NUDGE AFTERNOON TEMPERATURES DOWN A BIT AND ADJUST TIMING OF THE SHOWERS. && .AVIATION...ISSUED 646 AM EDT SAT SEP 21 2013 //DISCUSSION... DEEP LAYER MOISTURE HAS BEEN SWEPT EAST WITH THE COLD FRONT BUT STRATUS SHOULD PREVAIL THROUGH MOST OF THE DAY SLOWLY LIFTING THROUGH THE AFTERNOON. THIS OCCURS AS RESIDUAL BOUNDARY MOISTURE GETS TRAPPED UNDER A DEVELOPING INVERSION. DAYTIME HEATING WILL SLOWLY HELP IT LIFT BUT IT WILL LINGER UNTIL HIGH PRESSURE BRINGS INCREASINGLY DRIER AIRMASS INTO THE AREA EARLY TONIGHT. THERE IS A CHANCE OF SOME LIGHT SHOWERS FOR MBS/FNT AND POSSIBLY PTK BUT COVERAGE SHOULD BE TOO LOW TO INCLUDE IN THE TAFS. THE DETROIT TAFS SHOULD REMAIN BEYOND THE SOUTHERN PERIPHERY OF THE BETTER FORCING. WINDS WILL PRIMARILY BE OUT OF THE NORTHWEST THROUGH THE PERIOD ONLY WEAKENING TONIGHT AS THE HIGH BUILDS IN. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT EARLY THIS AFTERNOON INTO THIS EVENING. && .PREV DISCUSSION...ISSUED 340 AM EDT SAT SEP 21 2013 SHORT TERM...TODAY AND TONIGHT WITH THE COLD FRONT NOW TO OUR EAST...THE UPPER LEVEL TROUGH WILL ADVANCE THROUGH THE GREAT LAKES WHILE A SFC HIGH PRESSURE SYSTEM DROPS INTO THE REGION FROM CANADA. THE RESULT WILL BE A DEEP LAYER OF NW FLOW USHERING IN A COLD AIRMASS THROUGH THE STATE. MODELS SEEM TO HAVE A DECENT HANDLE ON THE COLD CORE OF THE SYSTEM AS THE RAOB NETWORK THROUGH CANADA RECORDED 500MB TEMPS OF -17C TO -22C AND 850MB TEMPS DOWN TO -5C. WITH COLD ADVECTION ALREADY COMMENCING...DAYTIME HIGHS WILL BE GREATLY LIMITED WITH MOST LOCATIONS FAILING TO GET OUT OF THE MID 60S. MODELS SHOW THE COLDEST AIR SLIDING THROUGH LAKE HURON THIS EVENING AND OVERNIGHT WITH 850MB TEMPS DROPPING TO AROUND -2C. WITH LAKE TEMPERATURES STILL UP AROUND 18C...THIS SETUP WILL FAVOR LAKE EFFECT CLOUDS AND SHOWERS AS DELTA T/S FALL IN THE 15-20C RANGE. HOW FAR THESE CLOUDS/SHOWERS CAN REACH INLAND IS THE QUESTION AS THE SFC HIGH WILL BE BRINGING IN INCREASINGLY DRIER AIR TO CONTEND WITH. MODEL SOUNDINGS ADVERTISE A GOOD AMOUNT OF MOISTURE JUST BELOW THE INVERSION BETWEEN 3-5KFT WHICH WOULD LEAD TO A GOOD AMOUNT OF STRATUS OVER THE AREA. A VORTICITY MAX DIVING THROUGH THE BASE OF THE TROUGH AND TRACKING THROUGH CENTRAL MI WILL FAVOR A CHANCE POP ACROSS THAT AREA. THE DRY AIR AT THE SFC WILL FAVOR A SLIGHT CHANCE FOR MOST OTHER AREAS SOUTHWARD. THE SFC HIGH WILL DRIFT FURTHER SOUTH TONIGHT CENTERING ITSELF OVER MI BY SUNDAY MORNING. THE CALM WINDS AND CLEARING SKIES WILL FAVOR A GOOD DEAL OF COOLING...ESPECIALLY ACROSS THE SAGINAW VALLEY WHERE TEMPS WILL LIKELY DIP INTO THE UPPER 30S NEAR 40. LOCATIONS FURTHER SOUTH CLOSER TO OHIO SHOULD STAY IN THE LOW/MID 40S. LONG TERM...SUNDAY THROUGH FRIDAY MUCH...IF NOT ALL...OF THE UPCOMING WEEK WILL BE QUIET AS HIGH PRESSURE BUILDS SOUTHEAST THROUGH THE GREAT LAKES ON ITS WAY TO THE EASTERN SEABOARD BY THE END OF THE FORECAST PERIOD. THE ONLY CHANCE OF PRECIPITATION THAT WILL BE CARRIED DURING THE LONG TERM FORECAST WILL BE MINOR (20-30% CHANCE) FOR LAKE EFFECT SHOWERS OVER SOUTHERN LAKE HURON THE THE IMMEDIATE SHORELINE IN THE THUMB REGION. WITH THE CANADIAN SURFACE HIGH BUILDING INTO THE AREA EARLY IN THE FORECAST...EXPECT TEMPERATURES TO START OFF RATHER COOL IN THE SUNDAY TO MONDAY TIME FRAME WITH HIGHS IN THE 50S/60S AND LOWS IN THE 30S/40S. AS HAS BEEN THE CASE WITH THE PREVIOUS TWO COOL SHOTS OF AUTUMN AIR...THE MAIN POTENTIAL FOR PATCHY/AREAS OF FROST WILL BE CONFINED MAINLY TO AREAS FROM THE I-69 CORRIDOR NORTH (AND ALSO AWAY FROM THE IMMEDIATE MODERATING EFFECT OF LAKE HURON). THAT SAID...THE COLDEST TWO MORNINGS (SUNDAY AND MONDAY) WILL LIKELY ONLY SEE LOWS DOWN IN THE MID/UPPER 30S IN THESE REGIONS...SO A WIDESPREAD FROST OR FREEZE IS NOT EXPECTED. TEMPERATURES WILL MODERATE THROUGHOUT THE WEEK AS THE SURFACE HIGH SHIFTS TO THE SOUTHEAST OF THE AREA AND RETURN SOUTHERLY FLOW AT THE SURFACE DEVELOPS AS AN UPPER RIDGE BUILDS INTO THE EASTERN CONUS. EXPECT HIGHS BACK INTO THE 70S BY WEDNESDAY-FRIDAY WITH A NUMBER OF LOCATIONS MORE THAN LIKELY PUSHING 80 BY THE THURSDAY/FRIDAY TIME FRAME. MARINE... THE COLD FRONT HAS PASSED TO OUR EAST WHICH HAS OPENED THE DOOR FOR COLD NORTHWEST FLOW TO SPREAD OVER THE GREAT LAKES. WITH LAKE TEMPERATURES STILL FAIRLY WARM...THE COLD AIR WILL LEAD TO INSTABILITY OVER THE WATER WHICH WILL PRODUCE LAKE EFFECT CLOUDS AND SHOWERS. THERE IS ALSO A WINDOW FROM SATURDAY NIGHT INTO SUNDAY AFTERNOON WHERE WATERSPOUTS WILL BE POSSIBLE. THE INCREASING NORTHERLY FLOW WILL ALSO LEAD TO ELEVATED WAVE HEIGHTS ALONG THE LAKE HURON SHORELINE THIS EVENING WARRANTING A SMALL CRAFT ADVISORY LASTING INTO SUNDAY. HIGH PRESSURE WILL SLIDE OVER THE STATE LATER ON SUNDAY THROUGH EARLY NEXT WEEK...RESULTING IN MORE IDEAL BOATING CONDITIONS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY...UNTIL MIDNIGHT SUNDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON...UNTIL 4 PM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....DRK SHORT TERM...DRK LONG TERM....DG MARINE.......DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 290708 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 308 AM EDT SUN SEP 29 2013 .SHORT TERM...TODAY AND TONIGHT A GOOD MOISTURE PLUME EXTENDED INTO THE WESTERN GREAT LAKES/OHIO VALLEY YESTERDAY EVENING...AS 00Z RAOBS INDICATED PW VALUES AROUND 1.50 INCHES (GRB/DVN/ILX)...ABOUT 200 PERCENT OF NORMAL. THE PROBLEM IS THE MAIN UPPER LEVEL FORCING IS DISPLACED WELL TO THE NORTH OVER ONTARIO. THUS...FRONTAL BOUNDARY PULLING EAST INTO THE CENTRAL GREAT LAKES TODAY LOOKS TO BE WEAKENING...AS WELL AS WELL AS LOSING SOME EASTWARD MOMENTUM. STILL...ENOUGH LOW LEVEL CONVERGENCE...RIGHT ENTRANCE FORCING AND DEEP LAYER SATURATION (15 KFT) TO SUPPORT A PERIOD OF LIGHT SHOWERS AS THE FRONT CROSSES SOUTHEAST MICHIGAN...PER 00Z NAM. LATEST AREA RADARS ALSO STILL SHOWING A NEARLY CONTINUOUS LINE OF SHOWERS EXTENDING INTO SOUTHERN ILLINOIS. CLOUDS AND SHOWERS SHOULD KEEP A LID ON MAX TEMPS TODAY...UPPER 60S TO AROUND 70 DEGREES...IN LINE WITH LATEST GUIDANCE. THE AMOUNT OF CLEARING TONIGHT IS A BIT IN QUESTION...AS FRONT WASHES OUT AND STALLS JUST EAST OF THE CWA. A LIGHT NORTHERLY WIND OFF LAKE HURON WILL NOT HELP THE DRYING OUT PROCESS...AND SEEMS LIKELY LOW LEVEL MOISTURE/CLOUDS WILL BE PRESENT EAST OF U.S. 23...WITH CLOUD DEPTHS EVEN POSSIBLY DEEP ENOUGH TO SUPPORT SPRINKLES. IF CLOUDS DO NOT PERSIST...FOG COULD BECOME AN ISSUE...AS WINDS ATTEMPT TO GO CALM. MINS EXPECTED TO BE PREDOMINATELY IN THE UPPER 40S TO LOWER 50S...ULTIMATELY DEPENDENT ON THE CLEARING OR LACK THERE OF. && .LONG TERM... MONDAY THROUGH SATURDAY GRADUAL ASCENSION IN THE UPPER HEIGHT FIELD WILL COMMENCE LOCALLY THROUGH THE EARLY WEEK PERIOD. THIS OCCURS IN RESPONSE TO THE COMBINATION OF A GENERALLY BLOCKED DOWNSTREAM EASTERN CONUS MID LEVEL FLOW AND THE PROGRESSIVE INTRUSION OF NORTHERN PACIFIC ENERGY INTO A ZONE OF DEFINED LOWERED HEIGHTS ARCING FROM THE WEST COAST INTO THE NORTHERN PLAINS. CLOUD COVER THE ONLY ISSUE ON MONDAY. ENVIRONMENT WILL STILL BE DEFINED BY A SLIGHTLY COOLER LOW LEVEL EASTERLY WIND COMPONENT...CAPPED BY A DEEP INVERSION AT 800 MB AND AN EXTENSIVE DRY LAYER ABOVE. QUESTION BECOMES WHETHER THE SUB-INVERSION MOISTURE DEPTH WILL REMAIN ADEQUATE...WITH SOME ENHANCEMENT VIA THE MOISTURE FLUX OFF THE LAKES...TO OFFSET DAYTIME MIXING AND DRYING FROM ABOVE. LATEST MOISTURE PROGS ALLOW FOR A SCT-BRIEF BKN COVERAGE OF CLOUD COVER INTO THE AFTERNOON. DIURNAL TEMPERATURE RESPONSE RELATIVELY STANDARD UNDER THIS SETUP...WITH PERIODIC OPEN SKY EASING HIGHS TOWARD THE 70 DEGREE MARK. THE EMERGING SOUTHWEST LOW LEVEL GRADIENT DEFINED AT THE EDGE OF THESE LOWERED HEIGHTS WILL ESTABLISH A NICE WARMING TREND STARTING ON TUESDAY. HIGHS BOTH TUESDAY AND WEDNESDAY WILL COMFORTABLY PUSH WELL INTO THE 70S. BENIGN WEATHER CONDITIONS THROUGH AT LEAST WEDNESDAY GIVEN THE CONSIDERABLE REDUCTION IN MOISTURE QUALITY...WEAK TROUGH ARRIVING ON WEDNESDAY YIELDING LITTLE MORE THAN SOME PATCHY MID CLOUD. THE EVOLUTION OF THE MEAN WESTERN CONUS TROUGH CONTINUES TO LEAVE A HIGHER DEGREE OF UNCERTAINTY FOR DOWNSTREAM LOCATIONS FROM THURSDAY ONWARD. MODEL TREATMENT OF THE GOVERNING SMALLER SCALE FEATURES DRIVING THE EVENTUAL AMPLIFICATION AND FORWARD PROPAGATION OF THE LONGWAVE TROUGH PROVIDING THIS DISPARITY IN TERMS OF BOTH STRENGTH AND TIMING AS THE ENTIRE TROUGH STRUCTURE WORKS EAST OF THE ROCKIES. A WEAKER CUTOFF LOW CENTERED OFF THE LOUISIANA COAST ALSO A SOURCE OF CONTENTION...INTRODUCING AN ADDITIVE TROPICAL MOISTURE COMPONENT SHOULD THE WAVE BE ABSORBED INTO THE EDGE OF THE ADVANCING LOWER HEIGHTS. THIS MOISTURE...AND PERHAPS THE BACKGROUND FORCING OF THE WAVE ITSELF...SEEMINGLY ARRIVES SOMETIME WITHIN THE THURSDAY-THURSDAY NIGHT WINDOW WITHIN THE BACKDROP OF INCREASING ISENTROPIC ASCENT. ATTENDANT FRONTAL PASSAGE CURRENTLY CENTERED ON THE FRIDAY PERIOD...BUT THIS TIMING AND THE INHERENT ASSOCIATED FORCING REMAINS SENSITIVE THE STILL ILL-DEFINED POSITIONING AND STRENGTH OF THE MAIN HEIGHT FALL CENTER. CHANCE POPS THROUGH THIS TIME WILL CERTAINLY SUFFICE AT THIS STAGE. NEXT WEEKEND LOOKING TO BE CONSIDERABLY COOLER...850 MB TEMPERATURES ADVERTISED IN THE LOWER SINGLE DIGITS THROUGHOUT THE WEEKEND. && .MARINE... SOUTHERLY WINDS OF 15 TO 25 KNOTS OVER LAKE HURON WILL DIMINISH AS COLD FRONT ARRIVES TODAY OVER THE CENTRAL GREAT LAKES...WITH WIND SHIFT TO THE NORTHWEST LATE TODAY. RIDGE OF HIGH PRESSURE BEHIND THE FRONT WILL ASSURE LIGHT WINDS TONIGHT AND MONDAY. MODEST SOUTHWEST WINDS WILL THEN DEVELOP AS WE HEAD INTO TUESDAY AHEAD OF OUR NEXT COLD FRONT. && .AVIATION...ISSUED 1154 PM EDT SAT SEP 28 2013 //DISCUSSION... CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT AHEAD OF AN APPROACHING COLD FRONT CURRENTLY RESIDING OVER LAKE MICHIGAN. THIS COLD FRONT IS EXPECTED TO REACH THE TERMINAL CORRIDOR LATE TONIGHT THROUGH SUNDAY MORNING. A SOLID MVFR CONDITION CONTINUES TO BE OBSERVED WITH THE FRONT OVER WISCONSIN AND IS EXPECTED TO HOLD AS THE FRONT MOVES THROUGH SE MICHIGAN...ALTHOUGH THE ASSOCIATED RAIN AND WIND PATTERN WILL WEAKEN WITH TIME AS IS THE CURRENT TREND IN UPSTREAM OBSERVATIONS. MODEST IMPROVEMENT IN NORTHWEST FLOW BEHIND THE FRONT IS EXPECTED BY SUNDAY AFTERNOON BUT LOW END VFR CONDITIONS WILL LIKELY CONSIST OF A SUB 5000 FT CEILING. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILING BELOW 5000 FT SUNDAY MORNING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....MR MARINE.......SF AVIATION.....KURIMSKI YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 160754 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 354 AM EDT WED OCT 16 2013 .SHORT TERM...TODAY AND TONIGHT THE MID LEVEL WAVE OVER WISCONSIN HAS BEEN WEAKENING OVER THE LAST SEVERAL HOURS. ALTHOUGH SOME PHASING WITH THE NORTHERN STREAM WAVE NOW DROPPING ACROSS NRN ONTARIO WILL OCCUR THIS MORNING...CONSENSUS AMONG THE 00Z MODEL SUITE IS FOR THE MID LEVEL CIRCULATION TO SLIDE NORTH OF LAKE HURON THIS AFTERNOON...LEAVING JUST A SHEARED MID LEVEL TROUGH AXIS TO MOVE ACROSS NRN AND CNTL LOWER MI THIS EVENING. THIS WILL SUSTAIN DEEP LAYER SOUTHWESTERLY FLOW ACROSS SE MI WELL INTO THE AFTERNOON AND WILL LEAD TO A RATHER SLOW PROGRESSION OF THE UPSTREAM COLD AIRMASS ACROSS SRN MI TODAY. THE SFC LOW /LOCATED OVER ERN UPPER MI AS OF 07Z/ WILL LIFT INTO ONTARIO THIS MORNING...WHILE THE ASSOCIATED COLD FRONT ADVANCES ACROSS SE MI OVER THE NEXT FEW HOURS. THE FINE LINE OF RETURNS WHICH HAS BEEN SHOWING UP ON RADAR NOW CROSSING THE SAGINAW VALLEY MARKS THE SFC COLD FRONT...WHICH WILL CROSS METRO DETROIT AROUND 09Z. CLOUDS HAVE BEEN CLEARING IN THE WAKE OF THIS FRONT AS A REGION OF LOW TO MID LEVEL DRY AIR IS ADVANCING INTO SE MI. OUTSIDE OF SOME LINGERING HIGH CLOUDS SOUTH OF METRO DETROIT...THIS DRY AIR WILL LEAD TO A PERIOD OF CLEAR SKIES TODAY. THIS WILL OFFSET THE COLD AIR ADVECTION TO SOME DEGREE AND ALLOW HIGHS TO REBOUND INTO THE MID 50S NORTH TO LOW 60S NEAR DETROIT AND MONROE. THE EXTENSIVE LOW CLOUDS NOW BLANKETING WISCONSIN WILL ADVANCE INTO SE MI TODAY. MODEL SOLUTIONS SUGGEST THIS MOISTURE WILL NOT MOVE INTO THE TRI CITIES UNTIL LATE MORNING AND METRO DETROIT UNTIL THIS EVENING. UPSTREAM OBSERVATIONS HOWEVER SUGGEST THE LOW CLOUDS ARRIVING MUCH SOONER...WHICH WILL SUPPORT A LITTLE MORE PESSIMISTIC AFTERNOON CLOUD FORECAST. CONTINUED COLD AIR ADVECTION DURING THE AFTERNOON AND EVENING WILL DEEPEN THE CONVECTIVE CLOUD DEPTHS AND LEAD TO INCREASED INSTABILITY OVER LAKE MICHIGAN. THE BEST CHANCES OF SOME LIGHT SHOWERS OR SPRINKLES WILL OCCUR ACROSS THE SAGINAW VALLEY/THUMB THIS AFTERNOON...THEN TRANSITION DOWN TO METRO DETROIT THIS EVENING AS THE LOW LEVEL FLOW OVER LAKE MI VEERS FROM W-SW TO W-NW. CONVECTIVE CLOUD DEPTHS WILL LOWER OVERNIGHT AS SHORT WAVE RIDGING ADVANCES INTO LOWER MI...SUPPORTING A REDUCTION IN POPS AFTER MIDNIGHT. && .LONG TERM...THURSDAY THROUGH TUESDAY AN INTERESTING MIX OF ORGANIZED DYNAMICS ARE SET TO SLIDE THROUGH SOUTHEASTERN MICHIGAN BETWEEN 12-00Z THURSDAY. MODELS ADVERTISE THE TRAILING PV ANOMALY NOW OVER THE FOUR CORNERS WILL REMAIN PROGRESSIVE ON THE BACK OF A CONSOLIDATED UPPER LEVEL JET CORE. OVERALL UPPER LEVEL DYNAMICS ARE WELL PUT TOGETHER...CENTER OF PV ADVECTION WILL SET ITS SIGHTS ON THE AREA ALONG WITH A GOOD AMOUNT OF LEFT EXIT REGION DYNAMICS. A DEPRESSION IN THE UPPER LEVEL JET STREAK AND D/DT IN CURVATURE SUGGESTS A RAMP UP IN DEFORMATION FORCING. DETERMINISTIC SOLUTIONS DO SUPPORT GOOD 700-500MB DEFORMATION WITH VERY LITTLE DOWN NEAR THE SURFACE. GENERALLY...THE QUALITY OF THERMODYNAMICS WILL BE THE LIMITING FACTOR. FAVORABLE WEAK STABILITY AND FRONTAL FORCING IS FORECASTED...BUT REALLY HIGH UP AT 10 KFT AGL AND ABOVE. IN ADDITION...MODEL SOUNDINGS DO SHOW STEEP LAPSE RATES IN A MINOR LAYER OF INSTABILITY BETWEEN 900-800MB...BUT THE ISSUE IS THERE IS VERY LITTLE GOING ON IN THAT LAYER FROM A FORCING MECHANISM STANDPOINT. WITH ALL OF THESE FACTORS WORKING IN THE BACKGROUND OF ISENTROPIC DOWNGLIDE...EXPECTATIONS ARE FOR YET ANOTHER EVENT WITH LESS THAN AWE INSPIRING QPF AMOUNTS. GENERALLY LOOKING AT A TENTH POSSIBLE WITH PERHAPS A HIGH END TWO TENTHS OF AN INCH. SHORTWAVE RIDGING AND LITTLE TO NO CHANGE IN THE UPPER LEVEL JET CONFIGURATION LOCALLY SUGGESTS NO WIDESPREAD FORCING FOR PRECIPITATION ON FRIDAY. ONLY THING TO WATCH WILL BE TROUGH AND COOLER MIDLEVEL AIR SETTLING INTO THE NORTHERN GREAT LAKES THROUGHOUT THE DAY. THE INHERITED FORECAST CARRIED A CHANCE ACROSS THE NORTH FOR THE AFTERNOON HOURS. THIS IS CERTAINLY REASONABLE AND WILL LEAVE ALONE. THE TROUGH AXIS IN THE VERY LARGE WAVELENGTH CANADIAN LOWER HEIGHT ANOMALY/ROSSBY WAVE WILL PIVOT THROUGH THE GREAT LAKES ON SATURDAY. THE OVERALL MASS ADJUSTMENT OF THIS PROCESS IS EXPECTED TO INDUCE HEIGHT FALLS AGAIN OVER LOWER MICHIGAN. THERE ARE MID TO HIGH CHANCE POPS GOING AND THIS IS GOOD. ONLY QUESTION MARK IS ON TIMING AND RIGHT NOW DO NOT HAVE MUCH OF A GUT FEELING THERE. WITH THE LOWERED HEIGHT ANOMALY...COOLER TEMPERATURES ARE EXPECTED SAT. FORECASTED HIGHS ARE ACROSS THE BOARD...8 DEGREES BELOW NORMAL. VIRTUALLY IMPOSSIBLE TO ANTICIPATE WHAT SHORTWAVE ENERGY TO TARGET FOR SUNDAY. CYCLONIC FLOW SUPPORTS A CHANCE POP...TEMPERATURES ARE NOT EXPECTED TO MODERATE MUCH OFF OF THE SATURDAY HIGHS. && .MARINE... THE PASSAGE OF A COLD FRONT EARLY THIS MORNING WILL LEAD TO INCREASING UNSTABLE CONDITIONS ACROSS THE LAKES AS COLD AIR ADVANCES INTO THE REGION. POST FRONTAL WINDS WILL BE SOUTHWESTERLY. UPSTREAM OBSERVATIONS SUGGEST FREQUENT GUSTS AT OR ABOVE 20 KNOTS. THE STRONGEST WINDS WILL OCCUR FROM SAGINAW BAY INTO CENTRAL LAKE HURON AS THE WINDS ARE FUNNELED ACROSS THE BAY. THE LOW LEVEL WINDS WILL VEER TO WEST TONIGHT AND WILL WEAKEN AS THE LOW PRESSURE SYSTEM NOW OVER ERN UPPER MI EXITS THE REGION TO THE NORTHEAST. AN EXTENDED PERIOD OF WEST-SOUTHWEST WINDS WILL THEN PREVAIL THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND. WINDS AND WAVES WILL GRADUALLY BUILD DURING THE WEEKEND AS MUCH COLDER AIR ADVANCES INTO THE GREAT LAKES REGION. && .AVIATION...ISSUED 1153 PM EDT TUE OCT 15 2013 //DISCUSSION... WITH MAIN AREA OF SHOWERS EXITING TO THE EAST...ONLY A THIN BAND OF CONVECTION REMAINS ALONG COLD FRONT. GIVEN THE FACT THAT THE BEST FORCING IS PULLING AWAY TO THE NORTH...WILL NOT MENTION SHRAS IN THE TAFS AS ANY PASSING ACTIVITY WILL BE SPOTTY/BRIEF. CIGS AROUND 1000 FEET WILL SHIFT ACROSS THE AREA INTO THE NIGHTTIME HOURS...BUT ERODE LATE TONIGHT INTO WEDNESDAY MORNING WITHIN WEDGE OF DRY SOUTHWEST FLOW. MOISTURE WILL THEN WRAP BACK INTO THE AREA BY MIDDAY...BUT BKN CIGS BY THAT TIME SHOULD REMAIN VFR. FOR DTW...1000 FOOT CIGS LOOK TO PERSIST TO 09Z-10Z. CLEAR/PARTLY CLOUDY PERIOD WEDNESDAY MORNING WILL WILL BRIEF AND WRAP AROUND MOISTURE ENHANCED BY DIURNAL HEATING WILL PRODUCE BKN VFR DECK BETWEEN 5-10KFT. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH 09Z. * LOW CONFIDENCE IN CEILINGS BELOW 5000 FEET AGAIN AFTER 00Z WEDNESDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...SAGINAW BAY...FROM 8 AM WEDNESDAY TO 10 PM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....CB MARINE.......SC AVIATION.....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 230753 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 353 AM EDT WED OCT 23 2013 .SHORT TERM... TODAY AND TONIGHT THE WEATHER THROUGH THE SHORT TERM WILL BE DOMINATED BY DEEP AND COLD CYCLONIC FLOW OVER THE GREAT LAKES. THIS WILL RESULT IN SCATTERED COVERAGE OF RAIN SHOWERS DURING THE DAY MODULATED BY SURFACE HEATING, AND PERHAPS A RAIN/SNOW SHOWER MIX WHERE LAKE EFFECT CAN BRUSH THE AREA TONIGHT. THE BEST CHANCE OF THAT WILL BE OFF THE SOUTH END OF LAKE MICHIGAN INTO THE OHIO BORDER REGION OVERNIGHT. STEADY COLD ADVECTION IN THE LOW LEVELS WILL RESTRICT MAX TEMPS TO THE 40S MOST LOCATIONS DESPITE SOME SUNSHINE DURING THE MORNING FOLLOWED BY MINS DROPPING OFF BELOW FREEZING TONIGHT, ESPECIALLY IN THE SAGINAW VALLEY AND INTERIOR THUMB WHERE SOME OPEN SKY WILL BE POSSIBLE AFTER MIDNIGHT. EARLY MORNING SATELLITE IMAGERY INDICATES SOME BREAKS IN THE CLOUD COVER OVER SE MICHIGAN DUE TO BOTH SUBSIDENCE TRAILING THE OHIO VALLEY WAVE AND A MORE DUE NORTHERLY LOW LEVEL WIND FLOW. THIS WILL QUICKLY GIVE WAY TO ANOTHER SPOKE OF SHORT WAVE ENERGY ROTATING AROUND THE UPPER LOW FROM CENTRAL CANADA. THE FEATURE WILL MOVE OVER LOWER MICHIGAN DURING THE AFTERNOON AND COMBINE WITH SURFACE HEATING TO GENERATE ENOUGH INSTABILITY FOR SCATTERED RAIN SHOWERS. THE COLD POOL ALOFT IS SHOWN TO REACH ABOUT -30C AT 500 MB, WHICH IS ABOUT 2 STANDARD DEVIATIONS BELOW NORMAL FOR THIS TIME OF YEAR. AT THE SAME TIME, MODEL SOUNDINGS INDICATE THE FREEZING LEVEL RISING TO ABOUT 2000 FEET AS THE BOUNDARY LAYER DEEPENS. THIS WILL ELIMINATE PROSPECTS FOR SNOW DURING THE DAY BUT IS LOW ENOUGH FOR GRAUPEL TO REACH THE GROUND IN CONVECTION THAT IS ABLE TO REACH SUFFICIENT INTENSITY. THIS POTENTIAL WAS BEING DEMONSTRATED OVER LAKE MICHIGAN DURING THE NIGHT WHERE CONVECTION WAS EVEN STRONG ENOUGH FOR A FEW LIGHTNING STRIKES. LAND BASED INSTABILITY WILL NOT BE AS STRONG BUT MODEL SOUNDINGS SHOW RESPECTABLE CAPE DENSITY BELOW 700 MB AND LIKELY AN ARTIFICIALLY LOW EQUILIBRIUM LEVEL ABOVE LEVELS WHERE SATURATION IS OCCURRING IN THE CLOUD LAYER. IT WILL BE MORE DIFFICULT TO PINPOINT FAVORED AREAS FOR ACTIVITY AS THE LOW LEVEL FLOW WILL LACK DISTINCT BOUNDARIES OR CONVERGENCE ZONES AS A FOCUSING MECHANISM. THERE IS LOOSE MODEL AGREEMENT FAVORING THE OHIO BORDER REGION DURING THE AFTERNOON INTO THE EVENING DUE TO ALIGNMENT OF THE UPPER WAVE AND CONVERGENT FLOW OFF THE SOUTH END OF LAKE MICHIGAN, BUT THIS IS USUALLY MORE EFFECTIVE AT NIGHT WHEN DECOUPLING OCCURS OVER THE LAND AREAS. FOR NOW, THE FORECAST WILL HAVE A GREATER CHANCE POP THERE TODAY AS WELL AS TONIGHT WHERE LONGEVITY OF LAKE EFFECT WILL GIVE A COUPLE OF SHOWERS A CHANCE TO MAKE IT OVER FROM LAKE MICHIGAN. THIS WILL OCCUR AS THE BOUNDARY LAYER COOLS ENOUGH, BASED ON MODEL SOUNDING TEMPERATURE PROFILES, FOR SOME SNOW TO MIX IN TOWARD SUNRISE THURSDAY. && .LONG TERM... PROSPECTS FOR LAKE EFFECT SHOWERS WILL REMAIN THE FORECAST PROBLEM THROUGH THURSDAY AS COLD CYCLONIC FLOW PERSISTS ACROSS THE GREAT LAKES. WITH LITTLE TO NO CHANGE IN THE RESIDENT AIRMASS, THE BASELINE FORECAST FOR THURSDAY IS ESSENTIALLY PERSISTENCE, WHICH IS TO SAY A MOSTLY CLOUDY SKY CONDITION OWING TO LAKE ENHANCED STRATOCU AND A GENERAL CHANCE OF SHOWERS. HOWEVER, THERE IS REASONABLE CONSENSUS AMONG THE 00Z GUIDANCE THAT DEEPER MOISTURE, MAINLY IN THE H85-H7 LAYER ASSOCIATED WITH A PASSING UPPER WAVE WILL RESULT IN DEEPER CONVECTIVE CLOUD DEPTHS AND A SUPERSATURATED LAYER EXTENDING UP TO 650MB. AS A RESULT, MAINTAINED THE BLANKET CHANCE POP IN ADDITION TO EXTENDING HIGH CHANCE INTO THE SAGINAW VALLEY DUE TO NW FLOW OFF OF LAKES SUPERIOR/MICHIGAN. SNOW POTENTIAL REMAINS MINIMAL. WARM BOUNDARY LAYER CONDITIONS MEAN POTENTIAL WILL BE ENTIRELY DEPENDENT ON WET-BULB EFFECTS WHICH WILL BE LIMITED TO THE DAYTIME HOURS CONVECTIVE INTENSITY/DEPTH IS MAXIMIZED. HOWEVER, PROGGED FREEZING LEVELS OF 1500-2000 FT DURING PEAK HEATING ARGUE AGAINST ANYTHING REACHING THE GROUND. CAN'T COMPLETELY RULE OUT A BRIEF BOUT OF FROZEN PRECIP DURING A HEAVIER SHOWER, BUT NOTHING CLOSE TO MEASURABLE. THEREFORE BACKED OFF SNOW CHANCES CONSIDERABLY FOR THE REMAINDER OF THE WEEK. CLOUD COVER WILL ONCE AGAIN CAST UNCERTAINTY ON OVERNIGHT LOWS, BUT STILL FEEL THAT LOWS AROUND ARE SUITABLY CONSERVATIVE GIVEN EXPECTED PERSISTENCE OF CLOUD COVER. SHORTWAVE RIDGING IN ADVANCE OF THE NEXT SYSTEM WILL WORK INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. THIS WILL ALLOW FOR AN AGGRESSIVE PUSH OF ANTICYCLONIC BOUNDARY LAYER FLOW WHICH SHOULD FINALLY ERODE LAKE INFLUENCES BY LATE IN THE AFTERNOON WITH THE HELP OF BACKING WINDS IN THE LOW LEVELS. THE ORIGINS OF THE NEXT SYSTEM, NOTED IN THE WV NEAR 150W/50N EARLY THIS MORNING, ARE PROGGED BY THE SUITE OF GUIDANCE TO SHEAR TOWARD THE GREAT LAKES FRIDAY NIGHT INTO SATURDAY. SO FAR, NWP SHOWING GOOD CONTINUITY IN THEIR DEPICTIONS OF THIS WAVE UNDERGOING RAPID AMPLIFICATION AS IT APPROACHES THE GREAT LAKES. THE RESULT WILL BE A NOTEWORTHY LOW-LEVEL JET RESPONSE AS A DEEPENING SURFACE LOW DIVES TOWARD THE NORTHERN GREAT LAKES. WITH 50+KTS AVAILABLE JUST OFF THE DECK AND A MODERATE TO STRONG SOUTHWEST GRADIENT AT THE SURFACE, INCREASINGLY GUSTY WINDS LOOK LIKE A GOOD BET BEGINNING LATE FRI NIGHT. PROGGED TIMING SUGGESTS THE STRONGEST WINDS ALOFT WILL SHIFT EAST PRIOR TO PEAK HEATING SATURDAY WHICH WILL LIMIT UPPER END GUST POTENTIAL, BUT THE FORECAST WAS STILL IN NEED OF A SIGNIFICANT UPWARD BOOST IN WIND GUSTS TO 25-30KTS ON SATURDAY. A QUICK HIT OF WARM ADVECTIVE PRECIP WILL BE POSSIBLE EARLY SATURDAY PRIOR TO COLD FROPA SATURDAY EVENING. && .MARINE... SMALL CRAFT ADVISORIES HAVE BEEN EXTENDED FOR OUTER SAGINAW BAY AND THE NEARSHORE WATERS OF SOUTHERN LAKE HURON AS COLD WEST TO NORTHWEST WIND WILL PERSIST OVER ALL MARINE AREAS DURING THE REST OF THE WEEK. THIS PATTERN WILL MAINTAIN GENERALLY UNSETTLED MARINE CONDITIONS BOTH IN TERMS OF PRECIPITATION AND WAVE CONDITIONS, ESPECIALLY OVER THE OPEN WATERS OF LAKE HURON WHERE INSTABILITY WILL BE GREATEST. WIND CONDITIONS WILL EASE FOR A SHORT TIME ON FRIDAY BUT WILL QUICKLY INCREASE AGAIN AHEAD OF THE NEXT LOW PRESSURE SYSTEM. EARLY INDICATIONS SHOW THIS SYSTEM WILL BE STRONG AS WELL WHILE MOVING INTO THE NORTHERN GREAT LAKES FROM CENTRAL CANADA DURING THE WEEKEND. && .AVIATION...ISSUED 1200 AM EDT WED OCT 23 2013 //DISCUSSION... THICKER CANOPY OF MID LEVEL CLOUD COVER /CIGS 7-10K FT/ ASSOCIATED WITH LOW PRESSURE LIFTING THROUGH THE OHIO VALLEY WILL GRADUALLY EXIT THE REGION THROUGH THE EARLY MORNING HOURS. WINDS VEER TO NORTHWESTERLY WITH A SURFACE TROUGH PASSAGE DURING THIS TIME. SOME DEGREE OF UPSTREAM LAKE MOISTURE TRANSPORT WILL CONTINUE IN STEADY COLD AIR ADVECTION. THIS MAY TRANSLATE INTO ADDITIONAL POCKETS OF VFR STRATUS FUNNELING INTO THE REGION THROUGH THE MORNING PERIOD. HOWEVER GREATER COVERAGE OF CLOUD COVER AND PROSPECTS FOR PRECIPITATION WILL PULL BACK CLOSER TO THE LAKESHORE AREAS UNDER THIS FLOW. VFR STRATOCU WILL INCREASE IN COVERAGE WITH SOME DIURNAL ENHANCEMENT ON WEDNESDAY. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILINGS FALLING BELOW 5000 FEET 02Z-08Z TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON INCLUDING OUTER SAGINAW BAY...UNTIL 8 PM THURSDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....JVC MARINE.......BT AVIATION.....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 042044 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 344 PM EST WED DEC 4 2013 .SHORT TERM...THROUGH TONIGHT LOW PRESSURE WILL DEEPEN AS IT TRACKS FROM IOWA/MINNESOTA TO NORTH OF LAKE SUPERIOR TONIGHT...AS THE UPPER WAVE DRIVING THE SYSTEM TAKES ON A NEGATIVE TILT. WARMER AIR WILL CONTINUE TO SURGE UP INTO LOWER MICHIGAN IN THE WARM SECTOR AHEAD OF THE SYSTEM TONIGHT. TEMPERATURES WILL REMAIN WELL INTO THE 40S AND EVEN 50S FOR MOST OF THE NIGHT BEFORE THEY START TO FALL TOWARDS DAYBREAK AS A STRONG COLD FRONT BEGINS TO PASS THROUGH THE AREA...STARTING AT AROUND 500 AM. PRECIPITATION CHANCES REMAIN A LITTLE MORE TRICKY TO FORECAST AS SEVERAL FEATURES ASSOCIATED WITH THE LOW PRESSURE SYSTEM MOVE ACROSS THE AREA. THE FIRST WILL BE A SECONDARY WARM FRONT NOW ORIENTATED NORTHWEST TO SOUTHEAST FROM NORTHERN INDIANA TO SOUTHERN OHIO. THIS BOUNDARY WILL LIFT UP ACROSS SOUTHEAST MICHIGAN THIS EVENING. SHOWERS ARE PRETTY SCATTERED ALONG THIS FRONT RIGHT NOW...BUT ANTICIPATE THEY SHOULD FILL IN A BIT AS THE LOW-LEVEL JET RAMPS UP (50 KNOTS) AFTER 21Z AND THE RIGHT ENTRANCE REGION OF AN UPPER JET LIFTING INTO THE UPPER MIDWEST BECOMES POSITIONED OVERHEAD. THERE SHOULD BE PLENTY OF MOISTURE AROUND FOR THE FORCING TO WORK WITH...WITH A REALLY GOOD THETA-E SURGE EXPECTED THIS EVENING (PW VALUES RISING TO ABOUT 1 INCH...HEALTHY FOR DECEMBER). OVERALL...CHANCES FOR MEASURABLE RAIN LOOK HIGHEST TONIGHT BETWEEN 21Z AND 02Z AS THIS ALL LIFTS THROUGH. BEYOND THAT...EXPECTING MORE A MORE SHOWERY PATTERN TO TAKE HOLD OVERNIGHT AHEAD OF THE COLD FRONT. DRY AIR ABOVE 700MB AND SATURATION IN THE LOWEST 100MB SHOULD EVEN LIMIT MUCH OF THE ACTIVITY TO DRIZZLE. ANTICIPATING A REDEVELOPMENT OF FOG OVERNIGHT AS WARM AIR AND MOISTURE CONTINUE TO GLIDE OVER THE COLD GROUND (SOIL TEMPS BELOW FREEZING DOWN TO ABOUT 5 INCHES...AS MEASURED AT DTX THIS AFTERNOON). SOUTH TO SOUTHEAST WINDS PICKING UP OVER 10 MPH OVERNIGHT SHOULD HELP LIMIT THE THREAT FOR WIDESPREAD DENSE FOG...BUT THIS IS STILL A POSSIBILITY THAT WILL HAVE TO BE MONITORED...ESPECIALLY IF WINDS END UP CALMER THAN EXPECTED. && .LONG TERM... THE SURFACE COLD FRONT IS EXPECTED TO CLEAR SOUTHEAST MICHIGAN AROUND 12Z THURSDAY...WITH GOOD RIDGING AND COLD ADVECTION FOLLOWING THROUGH THE DAY...AS 925 MB TEMPS FALL INTO THE MID NEGATIVE SINGLE NUMBERS BY DAY'S END...AND AROUND 10 BELOW ZERO BY FRIDAY MORNING...PER 12Z EURO. THIS WILL SUPPORT SLOWLY FALLING TEMPERATURES DURING THURSDAY. OUR MASSIVE UPPER LEVEL TROUGH AND ARCTIC AIR HAS NOW MOVED EAST INTO THE ROCKIES...AND STRONGLY CONFLUENT SOUTHWEST FLOW WILL EXIST OVER THE GREAT LAKES REGION. HOWEVER...WE ARE STILL LEARY OF MID LEVEL FGEN RESPONSE AS TWO JET STREAKS/PIECES OF ENERGY ROUND THE BASE OF THE TROUGH AND EJECT RAPIDLY NORTHEAST...WITH EARLY THURSDAY EVENING AND LATE FRIDAY LOOKING TO BE THE BEST ESTIMATE OF TIMING BASED ON MODEL CONSENSUS OF CANADIAN/EURO/GFS/NAM. HOWEVER...THERE IS LITTLE IF ANY BUCKLE OF THE FLOW...AS 850-700 MB MOISTURE/SPECIFIC HUMIDITIES SHOW A STEADY DECREASE THURSDAY THROUGH FRIDAY....WITH 850 MB MOISTURE MINIMUM IN PLACE OVER SOUTHERN LOWER MICHIGAN ON FRIDAY...AS DEW PT DEPRESSIONS CHECK IN AT AROUND -35 C FOR MOST OF SOUTHEAST MICHIGAN. THE EXCEPTION BEING TOWARD THE OHIO BORDER...WHERE WE WILL CONTINUE TO CARRY CHANCE POPS THURSDAY NIGHT-FRIDAY JUST IN CASE ONE OF THE UPPER WAVES IS A BIT STRONGER OR THE BAROCLINIC ZONE IS NOT DISPLACED AS FAR EAST. SPRAWLING HIGH PRESSURE (1040 MB) WILL BUILD INTO THE WESTERN GREAT LAKES REGION FOR SATURDAY. ARCTIC ORIGIN OF THE AIRMASS MAKES SKY FORECAST DIFFICULT WITH THE COLD WESTERLY FLOW (925 MB TEMPS IN THE MID NEGATIVE TEENS) OFF LAKE MICHIGAN. SUCH COLD AIRMASS COULD PRODUCE FLURRIES...BUT FORECAST IS SKEWED TOWARD MORE OPTIMISTIC... MOSTLY SUNNY FORECAST UNTIL WE FULLY RESOLVE WHAT LOOKS TO BE VERY LOW INVERSION HEIGHT/SHALLOW CLOUD DEPTH. HIGH PRESSURE BUILDS INTO THE GREAT LAKES ON SATURDAY AND WILL HOLD THROUGH SUNDAY MORNING BRINGING BELOW NORMAL TEMPERATURES TO MICHIGAN. BY SUNDAY AFTERNOON...A LOW PRESSURE SYSTEM WILL BE PUSHING CLOSER TO SE MI WITH THE MODELS SHOWING THE LOW TRACKING ACROSS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. MAIN CONCERN WITH THIS SYSTEM WILL BE PRECIPITATION TYPE AND TIMING AS IT LOOKS LIKE SE MI WILL BE MAINLY ALL SNOW WITH THE POTENTIAL FOR SOUTHEASTERN AREAS OF THE CWA SEEING A BRIEF RAIN/SNOW MIX MONDAY MORNING. SCATTERED SNOW SHOWERS MAY LINGER BEHIND AS THE LOW TRACKS OFF TO THE NORTHEAST MONDAY/TUESDAY AND NORTHWESTERLY FLOW SETS UP. HIGH PRESSURE WILL THEN BUILD BACK INTO THE AREA WEDNESDAY AND THURSDAY...WITH A REINFORCING SHOT OF EVEN COLDER AIR AS HIGHS ARE ONLY EXPECTED TO REACH AROUND 20 DEGREES. && .MARINE... STRONG EASTERLY WINDS GUSTING AROUND 30 KNOTS THIS AFTERNOON NORTH OF PRESQUE ISLE AS WARM FRONT LIFTS NORTH INTO THE CENTRAL GREAT LAKES. THIS WARM FRONT WILL BRING MUCH MILDER AIR TO THE REGION...LEADING TO MORE STABLE LOW LEVEL PROFILES...WHICH IS EXPECTED TO CAP THE WINDS OVER LAKE HURON AT AROUND 30 KNOTS. STRONG LOW OVER LAKE SUPERIOR LATE TONIGHT WILL BE TRACKING NORTHEAST AND THEN NORTH INTO JAMES BAY DURING THE DAY TOMORROW...WITH COLD FRONT PASSAGE OCCURRING EARLY IN THE DAY. PLENTY OF COLD AIR STREAMING IN DURING THURSDAY AND THURSDAY NIGHT WILL PROMOTE DEEPER MIXING...AND CONFIDENCE IS HIGH MANY LOCATIONS OVER LAKE HURON WILL GUSTS TO 30 KNOTS. ACROSS THE NORTH THIRD OF LAKE HURON WILL UPGRADE THE WATCH TO A WARNING. THE BIGGEST HANGUP IS WIND DIRECTION WILL BE SLIGHTLY SOUTH OF DUE WEST DUE TO THE LOW TRACK...AND WOULD PREFER DUE WESTERLY OR NORTHWEST TO FULLY MAXIMIZING CHANNELING THROUGH THE STRAIGHTS. EVEN SO...GALE FORCE WINDS SEEM LIKELY THURSDAY INTO THURSDAY NIGHT AS CANADIAN MODEL IS ALSO SHOWING A SURFACE TROUGH PASSING THROUGH DURING THE EARLY EVENING HOURS WHICH SHOULD ONLY HELP INCREASE THE WINDS. EXPANSIVE HIGH PRESSURE WILL BUILD IN FOR THE FIRST HALF OF THE WEEKEND...LEADING TO LIGHT WINDS. && .AVIATION...ISSUED 1240 PM EST WED DEC 4 2013 //DISCUSSION... CEILINGS AND VISIBILITIES WILL CONTINUE TO LIFT TO MVFR AND VFR THIS AFTERNOON. ADDITIONAL MOISTURE IS EXPECTED TO SURGE INTO THE AREA EARLY THIS EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. THIS SHOULD BRING ADDITIONAL RAIN SHOWERS...DRIZZLE...AND FOG BACK INTO THE AREA TONIGHT. THERE IS HIGH CONFIDENCE WITH IFR CONDITIONS FOR A PERIOD AT ALL SOUTHEAST MICHIGAN TERMINALS TONIGHT...ALTHOUGH TIMING OF OCCURRENCE IS STILL A LITTLE UNCERTAIN. THE BEST POTENTIAL WILL BE AFTER 01Z AND BEFORE A COLD FRONT WORKS WEST TO EAST ACROSS THE AREA BETWEEN 07Z AND 13Z. CONDITIONS WILL IMPROVE BEHIND THE FRONT ALTHOUGH MUCH COLDER AIR WILL WORK INTO THE REGION AND WEST WINDS WILL GUST TO 25 KNOTS THURSDAY FROM LATE MORNING THROUGH EARLY EVENING. FOR DTW...CONDITIONS WILL DETERIORATE AGAIN DURING THE VERY LATE AFTERNOON AND EVENING AS ADDITIONAL MOISTURE SURGES UP INTO SOUTHERN LOWER MICHIGAN. THE BEST TIMING FOR IFR CONDITIONS TO DEVELOP LOOKS TO BE JUST AHEAD OF THE FRONTAL PASSAGE...STARTING AT AROUND 07Z. WILL HAVE TO MONITOR POTENTIAL FOR IFR CONDITIONS TO DEVELOP AS EARLY AS 01Z HOWEVER. //DTW THRESHOLD THREATS... * LOW CONFIDENCE WITH CEILINGS AT OR BELOW 5000 FEET THROUGH 23Z...THEN HIGH CONFIDENCE WITH CEILINGS BELOW 5000 FEET THROUGH THURSDAY MORNING. * LOW CONFIDENCE WITH CEILINGS BELOW 200 FEET OR VISIBILITY BELOW 1/2 MILE TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362...FROM 7 AM THURSDAY TO 7 AM FRIDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 5 AM FRIDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT HURON...UNTIL 7 PM THURSDAY. SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 4 AM THURSDAY TO 10 PM THURSDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...HLO LONG TERM....SF/SS MARINE.......SF AVIATION.....HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 112051 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 351 PM EST WED DEC 11 2013 .SHORT TERM... AFTERNOON THROUGH TONIGHT A FAST-MOVING WAVE OF LOW PRESSURE WILL USHER AN ARCTIC COLD FRONT THE REST OF THE WAY THROUGH SE MICHIGAN DURING THE LATE AFTERNOON. LIGHT SYSTEM SNOW WILL CONTINUE TO FADE AS THE MID LEVEL WAVE SHEARS EASTWARD WHICH WILL LEAVE A NARROW BAND OF SNOW SHOWERS LEFT TO MOVE THROUGH WITH THE SURFACE FRONT. THIS BAND PERKED UP NICELY BETWEEN THE I-69 AND M-59 CORRIDORS DURING THE EARLY AFTERNOON AS THE BOUNDARY BECAME A HYBRID LAKE EFFECT CONVERGENT BAND AND SHALLOW FRONTAL CIRCULATION. THE KEY TO THE RESPONSE WAS THE LAKE MOISTURE INJECTED INTO AN ALREADY UNSTABLE LAYER BELOW 700 MB WITHIN THE FRONTAL CONVERGENCE ZONE. THIS ALLOWED THE VERTICAL MOTION FIELD WITHIN THE OTHERWISE SHALLOW FRONTAL CIRCULATION TO PRODUCE A BURST OF HEALTHY DENDRITES AND A QUICK ACCUMULATION UP TO AN INCH. THE BAND WILL REMAIN SIMILARLY OR SLIGHTLY LESS CAPABLE AS IT MOVES THE REST OF THE WAY THROUGH THE REGION BY 5 PM. COLD TEMPERATURES AND WIND CHILL READINGS WILL BE THE MAIN CONCERN FOR THE TONIGHT PERIOD. THE PASSAGE OF THE FRONT WILL OPEN THE DOOR ON AN ARCTIC AIR MASS THAT HAS CONFINED AFTERNOON TEMPERATURES TO THE SINGLE DIGITS BELOW ZERO OVER NORTHERN WISCONSIN. THE LAKE WILL ACT AS A BUFFER ON THIS AIR MASS THANKS TO WESTERLY WIND BUT NOT ENOUGH TO PREVENT MIN TEMPS FROM REACHING THE LOWER SINGLE DIGITS IN OUR AREA. DECREASING CLOUDS DURING THE EVENING AND LIGHT BUT FRESH SNOW COVER WILL ALSO CONTRIBUTE TO FALLING TEMPERATURES DURING THE NIGHT AND WILL LEAD TO SOME DECOUPLING OF THE SURFACE WIND. THE EXPECTATION IS THEN FOR A 10 TO 15 MPH WESTERLY WIND TO ACTUALLY HELP HOLD TEMPERATURES IN THE SINGLE DIGITS BUT REMAIN LIGHT ENOUGH FOR WIND CHILL NEAR BUT WARMER THAN THE -15F ADVISORY THRESHOLD THROUGH SUNRISE THURSDAY. && .LONG TERM... THERMAL TROUGH AXIS (850 MB TEMPS AROUND -20 C/-26 C AT 700 MB) OVER THE CENTRAL GREAT LAKES TO START THE DAY WILL PULL EASTWARD AS SURFACE HIGH OVER THE MIDWEST TRACKS ALONG/SOUTH OF THE OHIO RIVER DURING THE DAY. THE AIRMASS STILL WILL LIKELY BE SUFFICIENTLY COLD TO GENERATE SCATTERED LIGHT SNOW SHOWERS ACROSS NORTH HALF OF THE CWA AS SOUTHWEST WARM ADVECTION SETS IN OVER LAKE MICHIGAN WITH SATURATION AND LOW LEVEL CONVERGENCE NOTED 925-850 MB. THERE IS EVEN SOLID 700 MB FGEN/SATURATION NOTED WHICH COULD ALLOW FOR THE ACTIVITY TO BE EVEN MORE WIDESPREAD. NO COMPLAINTS WITH INHERITED MAXES...UPPER TEENS WHICH IS RIGHT IN LINE WITH LATEST GUIDANCE. WE WILL BE STUCK IN BAROCLINIC ZONE THURSDAY NIGHT INTO FRIDAY...WITH BACK DOOR COLD FRONT SLIDING DOWN FROM THE NORTHERN GREAT LAKES...RESULTING IN LOW LEVEL WIND SHIFT DURING FRIDAY. WITH LOW LEVEL CONVERGENCE AND MOISTURE FLUX COMING OFF LAKE HURON...SNOW SHOWERS ARE POSSIBLE...BUT WIND SHEAR FROM 925-850 MB RESULTING IN SHALLOW CLOUD DEPTHS WILL LIKELY PREVENT ACTIVITY FROM BEING AS ROBUST TO TODAY'S ARCTIC FRONT. THE FOCUS FOR FRIDAY NIGHT INTO SATURDAY CENTERS AROUND THREE DISTANT SHORTWAVES/UPPER WAVES...WHICH LOOK TO BE INTERACTING WITH EACH OTHER...BUT SIGNIFICANT PHASING BETWEEN THE WAVES DOES NOT APPEAR LIKELY...AS 12Z EURO INDICATES MORE OF AN INVERTED SURFACE TROUGH EXTENDING NORTHEAST. STILL...THE LEAD UPPER WAVE JUST OFF BAJA CALIFORNIA WILL DELIVER ENOUGH DEFORMATION/LOW LEVEL FGEN FORCING/MOISTURE ADVECTION TO SUPPORT SNOW FRIDAY NIGHT INTO SATURDAY...HIGHEST AMOUNTS TOWARD THE OHIO BORDER...WHERE 2.5+ G/KG OF SPECIFIC HUMIDITY IS NOTED AT 850 MB. THE OTHER FACTOR TO CONSIDER IS THE LONG FETCHED EASTERLY FLOW AT 925 MB OFF LAKE ERIE CONTRIBUTING TO THE FGEN/SNOWFALL TOTALS...AND COULD SEE 3-6 INCH SNOWFALL FOR LOCATIONS ALONG/SOUTH OF EIGHT MILE...WITH 1 TO 3 INCHES ELSEWHERE. THE 12Z EURO AND GFS LOOK TO BE IN PRETTY GOOD AGREEMENT FROM UPPER AIR/DYNAMIC TROPOPAUSE PERSPECTIVE. THIS IS A WELCOME TREND...AS THE 00Z EURO WAS OUTLIER WITH THE SECOND UPPER WAVE HANGING BACK ACROSS FAR SOUTHERN ARIZONA/NORTHERN MEXICO SATURDAY MORNING...CAUSING THE CENTER OF THE LEAD BAJA UPPER WAVE TO TRACK THROUGH KENTUCKY...WHICH WOULD BE TOO FAR SOUTH FOR APPRECIABLE SYNOPTIC SNOW. OBVIOUSLY...WE GOT A TIGHT BAROCLINIC ZONE/GRADIENT AND INITIALLY STRONG UPPER LEVEL CONFLUENT FLOW...COUPLED WITH THE SYSTEMS STILL OUT IN THE PACIFIC..CONFIDENCE IS AVERAGE AT BEST. HAVE INCLUDED A CHANCE OF SNOW SHOWERS FOR THE AREA FOR SATURDAY NIGHT THROUGH SUNDAY TO ACCOUNT FOR LINGERING SHOWERS FROM THE DEPARTING LOW PRESSURE SYSTEM. HIGH PRESSURE RETURNS ON SUNDAY TO THE SOUTHERN CWA WHILE A CLIPPER SYSTEM TRACKS ACROSS THE NORTHERN GREAT LAKES. THIS CLIPPER COULD BRING ANOTHER CHANCE FOR SOME SNOW TO THE SAGINAW VALLEY AND THUMB REGIONS. OTHERWISE...VERY COLD ARCTIC AIR FILTERS IN FOR SUNDAY NIGHT WITH LOWS IN THE SINGLE DIGITS AND WIND CHILLS DROPPING TO BELOW ZERO WITH SOME LOCATIONS SEEING WIND CHILLS DOWN TO -10 DEGREES. THE COLD AIR WILL STICK AROUND THROUGH MONDAY BEFORE SLIGHTLY WARMER AIR RETURNS /HIGHS IN THE MID 20S AND LOWS IN THE UPPER TEENS/ THROUGH MID WEEK. A SERIES OF DISTURBANCES WILL IMPACT THE REGION THROUGH MID WEEK...EACH BRINGING A CHANCE OF SNOW TO THE AREA. && .MARINE... WILL ALLOW THE REST OF THE GALE WARNINGS TO EXPIRE...AS WESTERLY GRADIENT HAS EASED JUST ENOUGH TO KEEP GUSTS TOPPING OUT AROUND 30 KNOTS. HIGH PRESSURE OVER THE MIDWEST (1041 MB) WILL SLIDE SOUTHEAST AND WEAKEN SLIGHTLY...BUT ANOTHER SURFACE COLD FRONT DROPPING SOUTH THROUGH THE NORTHERN GREAT LAKES WILL MAINTAIN WESTERLY WIND GUSTS AROUND 30 KNOTS FOR MUCH THE OPEN WATERS OF LAKE HURON TOMORROW. THE FRONT WILL SLOWLY SLIDE SOUTH THURSDAY NIGHT INTO FRIDAY...ALLOWING WINDS TO TURN TO THE NORTHEAST. NORTHEAST WINDS OF 15 TO 25 KNOTS ARE EXPECTED ACROSS ALL OF LAKE HURON BY FRIDAY NIGHT...WITH FUNNELING INTO SAGINAW BAY LEADING TO LARGE WAVES. && .AVIATION...ISSUED 1247 PM EST WED DEC 11 2013 //DISCUSSION... AN ARCTIC COLD FRONT MARKED BY A BAND OF HEAVIER SNOW SHOWERS WILL MOVE THE REST OF THE WAY THROUGH SE MICHIGAN DURING THE AFTERNOON, IMPACTING MAINLY THE DETROIT AREA TERMINALS THROUGH ABOUT 21Z. THE SNOW ALONG THE FRONT WILL BRING IFR TO BRIEFLY LIFR VISIBILITY RESTRICTION FOR AN HOUR OR TWO BEFORE CONDITIONS IMPROVE IN THE COLDER AIR BEHIND THE WIND SHIFT. THERE IS A CONSIDERABLE DIURNAL COMPONENT IN THE CLOUDS OBSERVED IN THE MBS AREA WHICH SUPPORTS THE IDEA OF A CLEARING TREND AFTER SUNSET LASTING THROUGH MUCH OF THE NIGHT. BACKING LOW LEVEL FLOW WILL THEN BRING SOME STRATOCU INTO THE TERMINAL CORRIDOR FROM LAKE MICHIGAN DURING THURSDAY MORNING WITH THE BEST POTENTIAL FOR MVFR CEILING NORTH OF PTK. FOR DTW...A QUICK POWDERY INCH OF SNOW IS LIKELY AS AN ARCTIC FRONT MOVES THROUGH THE REGION DURING THE AFTERNOON. THE BURST OF SNOW WILL BE BRIEF, LASTING ABOUT AN HOUR ASSOCIATED WITH THE IMMEDIATE FRONTAL PASSAGE AROUND 20Z. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILING BELOW 5000 FT DURING THE AFTERNOON. MODERATE CONFIDENCE THURSDAY MORNING. * HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH...UNTIL 7 PM THURSDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....SF/RK MARINE.......SF AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 151728 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1228 PM EST SUN DEC 15 2013 .AVIATION... //DISCUSSION... A SURFACE TROUGH IS JUST ABOUT THROUGH SOUTHEAST MICHIGAN...AND WESTERLY WINDS WILL BE GUSTING TO AROUND 25 KNOTS EARLY THIS AFTERNOON BEHIND THE TROUGH PASSAGE. FLURRIES AND LIGHT SNOW SHOWERS WILL PROBABLY PERSIST SEVERAL MORE HOURS...BUT DRIER AIR (MID LEVELS) WILL SHRINK CLOUD DEPTHS. THIS EVENING AND TONIGHT IS TOUGH CALL FOR CLOUD COVER...AND BANKING ON THE COLD WESTERLY FLOW OFF LAKE MICHIGAN TO PROVIDE JUST ENOUGH MOISTURE TO MAINTAIN HIGH MVFR/LOW VFR CEILINGS. IN ADDITION...THE VERY COLD AIRMASS WILL SUPPORT THE CHANCE OF FLURRIES JUST ABOUT ANYTIME...BUT ESPECIALLY TOMORROW MORNING AS SOME MID LEVEL MOISTURE ALSO RETURNS TO THE AREA. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5 KFT FT THROUGH THIS EVENING...MEDIUM CONFIDENCE OVERNIGHT INTO TOMORROW MORNING * MODERATE CONFIDENCE IN WESTERLY GUSTS REACHING 25KTS THIS AFTERNOON. && .PREV DISCUSSION...ISSUED 855 AM EST SUN DEC 15 2013 UPDATE... QUICK UPDATE TO CARRY WIDESPREAD SNOW SHOWERS...AS FLAKE SIZE IS PRETTY GOOD WITH SURFACE OBS REPORTING VSBYS 1-3 SM WITHIN THE HEAVIER ACTIVITY. 12Z DTX SOUNDING DOES SHOW STEEP LAPSE RATE IN THE 875-825 MB LAYER...WHICH IS EMBEDDED IN THE DENDRITIC SNOW GROWTH REGION. SURFACE TROUGH IS PROVIDING SUFFICIENT LOW LEVEL CONVERGENCE AS WELL. WITH GOOD FLUFF FACTOR...ACCUMULATIONS AROUND 1 INCH ARE EXPECTED. PREV DISCUSSION...ISSUED 357 AM EST SUN DEC 15 2013 SHORT TERM...TODAY AND TONIGHT THE SHORT TERM WILL FEATURE LIGHT SNOW...GUSTY AFTERNOON WINDS...AND POSSIBLE SINGLE DIGIT TEMPS OVERNIGHT. A NORTHERN STREAM UPPER LEVEL LOW WILL DROP THROUGH THE NORTHERN GREAT LAKES TODAY WHILE A LAKE AGGREGATE SURFACE TROUGH LINGERS ACROSS CENTRAL MI. STRONG CAA HAS BEGUN IN THE WAKE OF SATURDAYS LOW AS BROAD MID LEVEL TROUGHING SINKS INTO THE GREAT LAKES. THIS WILL USHER IN ANOTHER ARCTIC AIRMASS TO DEAL WITH THROUGH TONIGHT. MODELS SHOW SOME AIRMASS MODIFICATION AS IT CROSSES THE LAKES WITH -26C TEMPS AT 850MB ENTERING LAKE SUPERIOR AND NEGATIVE TEENS ENTERING MI. SOUTHERN MI WILL FALL NEAR THE BASE OF THE MID LEVEL TROUGH AND ON THE SOUTH SIDE OF THE SFC TROUGH LEADING TO WESTERLY FLOW. THE WESTERLY FLOW AND CAA WILL LEAD TO AN ACTIVE SETUP FOR LAKE EFFECT WITH MIXING LEVELS OVER LAKE MI REACHING 10KFT. EVEN OVER SE MI THE CAA IN THE LOW LEVELS WILL LEAD TO STRONG LAPSE RATES UP TO ABOUT 6KFT. BOTH THE NAM AND RUC SHOW THE ENTIRE MIXED LAYER TO BE SATURATED WHICH EXTENDS THROUGH THE DGZ. IN ADDITION TO THE SFC FEATURES...A MID LEVEL VORT MAX WILL ROTATE AROUND AND THROUGH MID MI LENDING SOME ADDITIONAL SYNOPTIC SUPPORT ALOFT. POPS WILL RAMP UP IN THE AFTERNOON AS THE DIURNAL CYCLE GIVES THE MIXED LAYER A BOOST AND AS THE SFC TROUGH AND VORT MAX SWING THROUGH. LAKE EFFECT SHOULD MAKE IT INTO THE CWA WITH THE STEADY WESTERLY FLOW DURING THE DAY. THE NAM IS ADVERTISING THE LAKE MI CONVERGENT BAND SETTING UP WHICH WILL NEED TO BE WATCHED IN CASE IT IMPACTS ANY ONE AREA FOR ANY DURATION...MOST LIKELY NEAR THE I94 CORRIDOR. OVERALL NOT EXPECTING MUCH SNOW WITH AROUND A HALF INCH FOR MOST LOCATIONS. IF WE CAN GET SOME ENHANCE MESOSCALE FEATURES TO SET UP OR THE LAKE EFFECT BAND TO PERSIST...TOTALS WOULD OBVIOUSLY GO UP SOME. THE OTHER CONCERN TODAY WILL BE THE WINDS. MODEL SOUNDINGS SHOW THE MIXING LEVELS PREVIOUSLY MENTIONED BRINGING DOWN GUST AROUND 30 MPH IN THE AFTERNOON. THIS WILL LIKELY LEAD TO ADDITIONAL DRIFTING OF THE SNOW PACK. THE LAST CONCERN WILL BE LOW TEMPS TONIGHT. WITH THE FRESH SNOW PACK AND ARCTIC AIR MOVING IN...THE POTENTIAL IS THERE FOR LOW SINGLE DIGIT TEMPS. A BIG CONCERN WILL BE CLOUD COVER PREVENTING THIS FROM ACTUALLY OCCURRING...ESPECIALLY ACROSS THE SOUTH WHERE THE LAKE CLOUD SHOULD PERSIST THE LONGEST. ADJUSTED TEMPS UP A COUPLE DEGREES ACROSS THE SOUTH WITH THE MORE PESSIMISTIC CLOUD COVER FORECAST...OTHERWISE CONTINUED THE COOL PLAY IN THE MID SINGLE DIGITS RESULTING IN WIND CHILL VALUES -5 TO -10F. LONG TERM...MONDAY THROUGH SATURDAY SHORTWAVE RIDGING WILL TRACK THROUGH THE CENTRAL GREAT LAKES MONDAY MORNING...KEEPING THE WEATHER DRY FOR THE FIRST HALF OF THE DAY. QUICKLY ON ITS HEELS WILL BE A VIGOROUS MID LEVEL SHORTWAVE DIVING SOUTH FROM CANADA. THIS ELONGATED MID LEVEL TROUGH...SEEN ON WATER VAPOR OVER WESTERN CANADA...WILL BRING A PROLONGED PERIOD OF LIGHT SNOW SHOWERS FROM MONDAY AFTERNOON THROUGH TUESDAY TO SOUTHEAST MICHIGAN. AS THE TROUGH MOVES THROUGH THE GREAT LAKES...IT WILL HAVE THE ASSISTANCE OF BEING UNDER THE LEFT EXIT REGION OF A 140 KNOT JET DIVING INTO THE WESTERN GREAT LAKES REGION. THE BEST TIME FOR SNOW APPEARS TO BE LATE MONDAY AFTERNOON INTO MONDAY NIGHT WHEN THE LEAD SHORTWAVE TRACKS THROUGH THE CENTRAL GREAT LAKES...WITH AN INCH OF TWO OF SNOWFALL ACCUMULATION POSSIBLE. A SUBTLE BUT NOTICEABLE WARMING IN THE LOW LEVELS SHOULD CAUSE LOW TEMPERATURES TO OCCUR EARLY MONDAY NIGHT...WITH SLOWLY RISING TEMPERATURES AFTER MIDNIGHT. ANOTHER SHORTWAVE TRACKING THROUGH THE SOUTHERN GREAT LAKES ON TUESDAY COULD BRING ADDITIONAL SNOWFALL AMOUNTS OF A FEW TENTHS OF AN INCH TO SOUTHEAST MICHIGAN. ONCE THIS SYSTEM MOVES OFF TO THE EAST HEIGHTS WILL INCREASE ACROSS THE CENTRAL GREAT LAKES WITH TEMPERATURES WARMING INTO THE 30S ON THURSDAY...WITH 40S POSSIBLE BY FRIDAY AHEAD OF THE NEXT LOW PRESSURE SYSTEM TRACKING THROUGH THE GREAT LAKES REGION. THIS SYSTEM...ORIGINATING OVER THE SOUTHERN PLAINS ON THURSDAY...WILL TRACK NORTHEAST THROUGH MICHIGAN ON FRIDAY. GIVEN THE NORTHERN TRACK OF THE LOW THE AREA WILL BE IN THE WARM SECTOR OF THE SYSTEM...MEANING PRECIPITATION MORE IN THE FORM OF LIQUID RATHER THAN ICE CRYSTALS. THERE ARE STILL TIMING DIFFERENCES BETWEEN THE LONG RANGE MODELS...NOTABLY THE FASTER ECMWF AND THE SLOWER GFS. HOWEVER THEY DO AGREE ON A RETURN TO COLDER TEMPERATURES BEHIND THE LOW BY SATURDAY AS RIDGING BUILDS OVER THE CENTRAL GREAT LAKES. MARINE... WAVES IN THE NEARSHORE ZONES CONTINUE TO SUBSIDE...WITH CONDITIONS HAVING FALLEN BELOW HEADLINE CRITERIA. HOWEVER...INCREASING WESTERLY WINDS THIS AFTERNOON ARE EXPECTED AS LOW PRESSURE TRACKS THROUGH THE CENTRAL GREAT LAKES. THE FETCH WILL BE FAVORABLE FOR WAVES TO BUILD UP OVER THE NORTHERN TIP OF THE THUMB OVERNIGHT...NECESSITATING A SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY AND THE LAKE HURON NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. CONDITIONS WILL REMAIN UNSETTLED INTO EARLY NEXT WEEK AS SOUTHWEST WINDS DEVELOP AHEAD OF A PASSING SYSTEM MONDAY NIGHT INTO TUESDAY. THERE ARE NO SIGNIFICANT WIND EVENTS ON THE HORIZON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SF UPDATE.......SF SHORT TERM...DRK LONG TERM....KURIMSKI MARINE.......KURIMSKI YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 240803 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 303 AM EST TUE DEC 24 2013 .SHORT TERM...TODAY AND TONIGHT AN AXIS OF ENHANCED SURFACE CONVERGENCE SET UP MUCH FARTHER NORTH THAN EXPECTED LAST EVENING /JUST SOUTH OF SAGINAW/. THIS WAS THE RESULT OF A DEEP MESO VORTEX WHICH DEVELOPED OVER LAKE MI OFF THE COAST OF MUSKEGON CO /ALSO FARTHER NORTH THAN EXPECTED/. HIGH PRESSURE HAS BEEN BUILDING ACROSS THE UPPER MS VALLEY EARLY THIS MORNING WITHIN STRONG MID LEVEL SUBSIDENCE BEHIND A SHARP MID LEVEL TROUGH AXIS. THIS IN TURN HAS TIGHTENED THE NORTHERLY GRADIENT OVER ERN LAKE MI AND IS ALLOWING THE VORTEX TO PUSH SOUTH ALONG THE WRN MI SHORELINE. THIS AND SLIGHT PRESSURE RISES OVER CENTRAL LOWER MI WILL ALLOW THE CONVERGENCE AXIS TO SLIDE ACROSS METRO DETROIT/ANN ARBOR TO THE OHIO BORDER THIS MORNING. RECENT OBSERVATIONAL TRENDS SUGGEST THE CONVERGENCE WEAKENING. THIS TREND SUPPORTS A DECREASE IN THE COVERAGE OF SNOW SHOWERS AS THEY WORK THROUGH METRO DETROIT. HOWEVER...THE MID LEVEL TROUGH AXIS WILL PASS OVERHEAD THIS MORNING WHICH WILL INCREASE THE CONVECTIVE CLOUD DEPTHS. THUS SOME OF THESE SNOW SHOWERS WILL STILL PRODUCE BRIEF PERIODS OF INTENSE SNOW AND WILL BE CAPABLE OF DROPPING A QUICK DUSTING TO HALF INCH OF ACCUMULATION. THERE ARE SOME INDICATIONS OF A DEVELOPING MESO VORTEX SETTING UP OVER THE SRN LAKE HURON BASIN PER EXETER ONT RADAR. RISING CONVECTIVE DEPTHS THIS MORNING SUGGEST SOME CONTINUED DEVELOPMENT OF THIS CIRCULATION. ENHANCED N-NE FLOW TO THE WEST OF THIS VORTEX WILL LIKELY BRING SOME SNOW BANDS INTO THE LAKE HURON SHORELINE FROM PORT HOPE DOWN TO PORT HURON AND WILL SUPPORT SOME MINOR ACCUMS. HIGH PRESSURE BUILDING ACROSS LOWER MI THIS AFTERNOON AMIDST GOOD LARGE SCALE SUBSIDENCE SHOULD KEEP THE MORE PROLONGED SNOW SHOWERS OVER THE LAKE AND INTO ONTARIO...BUT OFF COURSE WILL BE SOMETHING TO MONITOR IN THE NEAR TERM. ARCTIC AIR WILL CONTINUE TO OVERSPREAD SE MI THIS MORNING AND WILL LEAD TO A COLD DAY WITH AFTERNOON TEMPS LIKELY STUCK IN THE TEENS FOR MOST OF THE AREA. THERE WILL BE A SHORT WINDOW OF GOOD RADIATIONAL COOLING THIS EVENING...PARTICULARLY NORTH OF THE M 59 CORRIDOR WITH SOME FRESH SNOW. TEMPS WILL LIKELY DROP QUICKLY AFTER SUNSET BEFORE AN INCREASED SOUTHERLY GRADIENT AND INCREASING CLOUD COVER LEADS TO A STEADY RISE IN TEMPS OVERNIGHT INTO EARLY CHRISTMAS MORNING. && .LONG TERM... STILL LOOKING AT LIGHT SNOW FOR CHRISTMAS...BUT ACTUALLY LIKING THE SECOND STRONGER NORTHERN STREAM UPPER WAVE/ASSOCIATED COLD FRONT COMING THROUGH CHRISTMAS NIGHT EQUALLY AS WELL. WATER VAPOR IMAGERY SHOWS LOT OF ENERGY/UPPER LEVEL TROUGH ENTERING THE ROCKIES...WITH MAIN PV CENTER TRACKING THROUGH IDAHO. A GOOD DEAL OF THIS ENERGY WILL BE DIVING SOUTHEAST...REACHING THE SOUTHERN PLAINS TONIGHT AND THEN BEING SHEARED APART...AND THUS THE SHORTWAVE TROUGH MOVING THROUGH LOWER MICHIGAN IS NOT VERY IMPRESSIVE AND DAMPENING OUT...WITH THE NORTHERN STREAM TROUGH DIGGING THROUGH THE UPPER MISSISSIPPI VALLEY MUCH BETTER DEFINED. BOTH TROUGHS WILL HAVE ABOUT 2 G/KG OF SPECIFIC HUMIDITY TO WORK WITH AT 850 MB...BUT THE LEAD WAVE NEEDS TO OVERCOME THE INITIAL VERY DRY LOW LEVELS FROM THE RETREATING ARCTIC AIR OVER SOUTHEAST MICHIGAN. GOOD LAKE CONTRIBUTION WITH THE MAIN TROUGH/COLD POOL (-14 TO -16 C AT 850 MB) CHRISTMAS EVENING/NIGHT...AND BETTER INSTABILITY/SUPERSATURATION WITH RESPECT TO ICE DOWN LOW TOWARD 12Z THURSDAY WITH SOUTHWEST TO WESTERLY FLOW...AND THUS THINK BETTER SNOWFALL RATES WILL BE WITH THIS ONE...BUT MAYBE NOT AS GOOD AREAL COVERAGE. THE GFS IS MORE BULLISH ON THE QPF DURING CHRISTMAS DAY...BUT CANADIAN/UKMET/EURO ARE MORE IN LINE WITH MY PREFERENCE. BASICALLY...THINKING EACH SYSTEM WILL PRODUCE AROUND 1 INCH OF SNOW (0.5-1.5")...WITH HIGHER TOTALS COMING IN ACROSS THE NORTH. THUS...24 HOUR TOTALS IN THE 1 TO 3 INCH RANGE. COLD WESTERLY FLOW DURING DURING THURSDAY LOOKS LIKE THERE WILL BE ADDITIONAL SNOW SHOWERS (SCATTERED AT THE VERY LEAST)...AS INVERSION HEIGHTS REMAIN ABOVE 5 FEET...WITH NAM SOUNDINGS STILL SHOWING SIZEABLE LAYER OF SUPERSATURATION WITH RESPECT TO ICE IN DENDRITIC SNOW GROWTH ZONE. HIGH FLUFF FACTOR COULD LEAD TO ADDITIONAL INCH IN SPOTS. && .MARINE... MODEST NORTHERLY FLOW WILL REMAIN IN PLACE ACROSS LAKE HURON THROUGH TODAY...AS WINDS PEAK IN THE 15 TO 20 KNOT RANGE WITH GUSTS TO 25 KNOTS THIS MORNING OVER SOUTHERN SECTIONS OF THE LAKE. WINDS WILL SHIFT TO SOUTHWEST AND INCREASE ON WEDNESDAY IN ADVANCE OF A COLD FRONT. THE POTENTIAL EXISTS FOR A PERIOD GALES DURING THE DAY ACROSS MOST OF THE OPEN WATERS. THE COMBINATION OF THE WIND AND A COLD RESIDENT ENVIRONMENT WILL PROMOTE SOME FREEZING SPRAY THROUGH THIS TIME. GRADIENT WILL EASE WEDNESDAY NIGHT WHILE GRADUALLY VEERING TO WESTERLY. MODERATE WESTERLY WINDS WILL PERSIST FOR THE DAY ON THURSDAY...WITH DEEP MIXING AND CHANNELING PRODUCING WIND SPEEDS AROUND 30 KNOTS ACROSS NORTH THIRD OF LAKE HURON. && .AVIATION...ISSUED 1205 AM EST TUE DEC 24 2013 //DISCUSSION... THE HYBRID LAKE EFFECT SNOW BAND/COLD FRONT WILL SETTLE SLOWLY THROUGH THE TERMINAL SITES DURING THE MORNING, STARTING FROM FNT AT PRESS TIME AND REACHING DTW AROUND 14Z. THE SNOW SHOWERS WILL BE MOST ACTIVE IN THE FNT TO PTK AREA DURING THE REST OF THE NIGHT WHERE FREQUENT IFR RESTRICTION WILL BE IN PLACE. THERE REMAINS SOME QUESTION ON HOW MUCH STRENGTH THE BANDS OF SNOW WILL BE ABLE TO PRESERVE WHILE REACHING DTW, BUT A SOLID MVFR CONDITION IS EXPECTED UNTIL THE TROUGH EXITS INTO OHIO SHORTLY AFTER MID MORNING. VFR WILL THEN BE CARRIED INTO SE MICHIGAN BY HIGH PRESSURE BUILDING THROUGH THE OHIO VALLEY DURING THE AFTERNOON AND INTO TUESDAY EVENING. FOR DTW... THE BAND OF SNOW SETTING UP IN THE FNT TO PTK AREA WILL SETTLE SOUTHWARD DURING THE REST OF THE NIGHT AND ARRIVE IN THE DTW AREA LATE. THERE IS SOME QUESTION AS TO HOW STRONG THE BAND OF SNOW WILL BE BY THEN BUT A DUSTING OF ACCUMULATION SHOULD BE EXPECTED. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH TONIGHT. * HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WATCH...LHZ362-LHZ363-LHZ462-LHZ463-LHZ464...FROM 8 AM WEDNESDAY TO 7 PM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....SF MARINE.......SF AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 201945 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 345 PM EDT TUE MAY 20 2014 .SHORT TERM... THROUGH TONIGHT SHORT TERM CONCERNS STILL REVOLVE AROUND CONVECTIVE TRENDS AND POTENTIAL FOR SEVERE WEATHER. FIRST...FOR THE REMAINDER OF THIS AFTERNOON INTO THE EVENING. FAST ZONAL UPPER LEVEL FLOW IS OVER THE UPPER MIDWEST BETWEEN A RIDGE OVER THE SOUTHERN PLAINS AND A TROUGH OVER SOUTHERN MANITOBA/SOUTHWESTERN ONTARIO. 18Z SURFACE ANALYSIS SHOWED A WARM FRONT ARCING SE INTO MICHIGAN FROM ROUGHLY NORTH OF MUSKEGEON TO LAPEER AND THEN SOUTH TO AROUND MONROE. THE NORTH/EASTWARD PROGRESS OF THE FRONT IS BEING HINDERED BY FLOW OFF THE COOLER LAKES. TEMPS CONTINUE TO WARM INTO THE LOW/MID 70S SOUTH OF THE FRONT WITH DESPOINTS IN THE LOW 50S TO NEAR 60. SOME CUMULUS IS DEVELOPING OVER SOUTHWESTERN LOWER IN THE LEE OF LAKE MICHIGAN...BUT SO FAR IT IS SHALLOW. MIDLEVEL LAPSE RATES ARE FAIRLY MEAGER BUT SHOULD INCREASE INTO THE EVENING. SOME MODEST SURFACE BASED INSTABLITY MAY DEVELOP AS WE GET LATER INTO THE AFTERNOON AND EVENING. DEEP LAYER SHEAR OF 35-50KT IS FAVORABLE FOR ORGANIZED CONVECTION SHOULD ANYTHING DEVELOP...BUT THE LACK OF CLEAR FORCING MECHANISMS AND GREATER INSTABILITY WILL KEEP POPS IN THE LOW CHANCE RANGE THROUGH 00Z. ANOTHER THREAT IS EXPECTED TO DEVELOP AFTER 04Z...BUT IT IS FAR FROM CERTAIN. DISCRETE CELLS ARE EXPECTED TO DEVELOP OVER NORTHERN ILLINOIS LATE THIS AFTERNOON. THESE STORMS MAY EVOLVE INTO ONE OR MORE FORWARD-PROPAGATING QUICK-MOVING MCS...WHICH COULD BE LONG-LIVED DUE TO CONTINUED STRONG DEEP-LAYER SHEAR AND APPRECIABLE INSTABILITY. THIS SCENARIO IS SUPPORTED BY THE 16Z HRRR AND THE 12Z NMM. THESE COMPLEXES WOULD PREFERENTIALLY MOVE TOWARD THE RESERVOIR OF GREATER INSTABILITY...WHICH IS BETTER TO OUR SOUTH WHERE THE GREATER MIDLEVEL LAPSE RATES WILL RESIDE. STILL...THE THREAT IS GOOD ENOUGH TO INCLUDE A SLIGHT CHANCE OF SEVERE WEATHER FROM M-59 SOUTH /WITH THE BEST CHANCES NEAR THE OHIO BORDER/ FROM AROUND 04-10Z. DAMAGING WIND WOULD BE THE MAIN THREAT...WITH LARGE HAIL AND AN ISOLATED TORNADO SECONDARY. HEAVY RAIN IS ALSO POSSIBLE AS PWATS INCREASE TO 1.3-1.5 INCHES. && .LONG TERM... LARGE UPPER LEVEL LOW SLOWLY WORKING THROUGH ONTARIO TOMORROW...DROPPING SOUTHEAST INTO NEW ENGLAND THURSDAY NIGHT INTO FRIDAY WILL DELIVER A RESPECTABLE SHOT OF COOL AIR TO SOUTHEAST MICHIGAN THURSDAY INTO FRIDAY...BEFORE TEMPERATURES QUICKLY MODERATE OVER THE WEEKEND AS AMPLIFIED UPPER LEVEL RIDGE BUILDS INTO THE GREAT LAKES REGION...LIKELY LEADING TO EVEN WARMER TEMPERATURES (80+ DEGREES) EARLY NEXT WEEK. AS FAR AS TOMORROW GOES...THE FORECAST WILL BE IMPACTED WITH WHAT OCCURS OVERNIGHT...AS POTENTIAL DEPARTING MCV MAY CAST SHADOW/SUBSIDENCE WAKE THROUGH A GOOD PORTION OF THE DAY. OTHERWISE...DO HAVE SHORTWAVE TROUGH AXIS EXTENDING FROM THE PREVIOUS MENTIONED UPPER LEVEL LOW OVER ONTARIO...WHICH WILL CAUSE SURFACE COLD FRONT TO SWING THROUGH DURING THE PEAK DIURNAL CYCLE. STRONG WESTERLY JET (65 KNOTS AT 500 MB) CORE WILL BRING AN INCREASED RISK OF DAMAGING WINDS IF THUNDERSTORMS ARE ABLE TO DEVELOP DURING THE AFTERNOON HOURS. THE PROBLEM IS WE CAN NOT FULLY COUNT ON A MORNING CAP/LULL...AND STORMS COULD EASILY DEVELOP EARLIER IN THE DAY. DURING THE AFTERNOON HOURS...THE INCREASING MIXING DEPTHS WE ACCELERATE THE WESTERLY DRYING OUT PROCESS...LEADING TO QUESTIONS WITH THE AREAL COVERAGE OF THE POTENTIAL STORMS DEVELOPING ALONG THE COLD FRONT...AS MAX INSTABILITY LOOKS TO BE OVER THE NORTHERN OHIO VALLEY. WITH THAT SAID...IT LOOKS FAIRLY LIKELY SOMETIME DURING THE 12 HOUR WINDOW...NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR...AND UNFORTUNATELY WILL CARRY GENERIC HIGH SCATTERED/LOW LIKELY POPS THROUGH THE DAY...AS TONIGHT'S EVOLUTION WILL BE A ONE OF THE KEYS FOR TOMORROWS WEATHER. STRONG NORTHWEST FLOW WEDNESDAY NIGHT INTO THURSDAY...WITH 850 MB TEMPS FALLING INTO THE MID SINGLE NUMBERS. THE CYCLONIC/COLD ADVECTION AND STEEP LOW LEVEL LAPSE RATES SHOULD BE SUFFICIENT TO GENERATE PLENTY OF CLOUDS DURING THE DAYTIME HOURS OF THURSDAY...LIKELY CAPPING MAXES IN THE UPPER 60S TO AROUND 70 DEGREES. ANOTHER PIECE OF ENERGY ROTATING SOUTH THROUGH THE CENTRAL GREAT LAKES ON FRIDAY SHOULD MAINTAIN THE COOLER TEMPERATURES AND CONSIDERABLE CLOUDS DURING THE DAYTIME HOURS...AND EVEN SUFFICIENT DIURNAL INSTABILITY/CAPES/CLOUD DEPTHS (4-12 KFT) TO POSSIBLY PRODUCE ISOLATED LIGHT SHOWERS. 12Z EURO IS IN DECENT AGREEMENT WITH THE CANADIAN/GFS IN BUILDING UPPER LEVEL RIDGE OVER THE CENTRAL GREAT LAKES ON MONDAY...SUPPORTING HIGHS IN EXCESS OF 80 DEGREE WITH INCREASING SOUTHWEST FLOW AND 850 MB TEMPS WARMING INTO THE MID TEENS INTO TUESDAY. && .MARINE... INCREASED SOUTHEAST FLOW OVER OUTER SAGINAW BAY AND THE ADJACENT NEARSHORE WATERS DUE TO THUNDERSTORMS TRACKING THROUGH THE AREA WILL DIMINISH AS WARM FRONT WEAKENS TONIGHT. A STRONG COLD FRONT WILL SWING THROUGH THE CENTRAL GREAT LAKES TOMORROW AFTERNOON...WITH BRISK NORTHWEST WINDS FOLLOWING FOR WEDNESDAY NIGHT AND THURSDAY. ANY THUNDERSTORMS WHICH DEVELOP TONIGHT THROUGH TOMORROW MAY BE STRONG TO SEVERE. COOLER AND MORE STABLE AIRMASS WILL FILTER INTO THE REGION THURSDAY AND FRIDAY...BUT ISOLATED SHOWERS ARE STILL POSSIBLE. A LARGE UPPER LEVEL RIDGE BUILDING INTO THE GREAT LAKES REGION OVER THE WEEKEND WILL LEAD TO WARMUP TEMPERATURES AND LIGHT WINDS. && .AVIATION...ISSUED 200 PM EDT TUE MAY 20 2014 //DISCUSSION... VFR CONDITIONS FOR MUCH OF THE AFTERNOON AND EVENING AS SKIES ARE CLEARING OUT WITH A WARM FRONT LIFTING INTO SOUTHWEST MICHIGAN. THERE IS A SLIGHT CHANCE THAT SOME STORMS WILL FIRE ALONG THE FRONT TO OUR WEST AND TRACK INTO THE AREA BUT CHANCES ARE TOO LOW TO MENTION IN THE TAFS AT THIS TIME. THE BETTER CHANCE FOR SHOWERS/THUNDERSTORMS WILL BE OVERNIGHT AS MODELS INDICATE A MCS DEVELOPING AND TRACKING ACROSS SOUTHERN MICHIGAN. CONDITIONS WILL DETERIORATE WITH THE ADDITIONAL MOISTURE AND PRECIPITATION IN THE AREA. EXPECT MVFR/IFR CONDITIONS FROM 05Z UNTIL AROUND DAYBREAK WEDNESDAY WHEN WE START BURNING OFF SOME RESIDUAL MOISTURE. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILING BELOW 5000 FEET AFTER 05Z TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DT LONG TERM....SF MARINE.......SF AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 260758 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 358 AM EDT SUN APR 26 2015 .SHORT TERM...TODAY AND TONIGHT SUPPRESSION OF GEOPOTENTIAL HEIGHTS OVER THE SOUTHEASTERN UNITED STATES WILL ALLOW THE BROADENING CLOSED LOW ANOMALY OVER PORTIONS OF NORTHEASTERN NORTH AMERICA TO REACH BACK AND REGAIN AN INFLUENCE OVER THE GREAT LAKES REGION TODAY AND TONIGHT. THE STRENGTHENING DEEP COLUMN CYCLONIC FLOW WILL NOT ONLY BRING ANOTHER DAY OF BELOW NORMAL TEMPERATURES...IT WILL BACKDOOR A COUPLE OF SPOKES OF WEAK SHORTWAVE ENERGY AND RIBBONS OF DEEPER MOISTURE FROM NORTHEAST TO SOUTHWEST ACROSS LAKE HURON AND DOWN INTO INTERIOR SECTIONS OF THE LOWER PENINSULA. FOR THE SHORT TERM FORECAST...THE ITEM OF UNCERTAINTY IS WHEN CLOUDS WILL PUSH ACROSS THE LAKE AND SPREAD ACROSS THE CWA. THE MODEL CONSENSUS IS VERY BULLISH...SUGGESTING CLOUDS WILL BE HERE ALREADY BY MID TO LATE MORNING. THE PROBLEM IS CURRENT...IR SATELLITE IMAGERY SHOWS AREAS VOID OF CLOUD CLEAR BACK ACROSS LAKE HURON TO ONTARIO. THE POCKET OF CLOUD THAT HAD ADVECTED DOWN INTO THE SAGINAW BAY AREA EARLIER HAS SINCE ERODED. FOR SKY COVER...WENT WITH A BLEND OF GUIDANCE AND GUT FEELING. OVERALL...FAVOR MORE SUN DURING THE MORNING BEFORE CLOUDS INCREASE DURING THE AFTERNOON EITHER FOR INCREASE IN DIURNAL CUMULUS/STRATOCUMULUS OR ADVECTION OF MIDLEVEL CLOUD. ADDING TO THIS POINT...FIRST SPOKE OF CVA IS EXPECTED TO COLLAPSE DOWN UPON THE AREA DURING THE LATE AFTERNOON. THE SECOND SPOKE OF MIDLEVEL ENERGY WILL ARRIVE LATE TONIGHT...LIKELY AFTER 9Z. MODEL SOUNDINGS SUPPORT A FAIRLY RESPECTABLE DEPTH OF DEEPER MOISTURE WITH THIS SECOND WAVE. KEPT THE SLIGHT TO LOW CHANCE OF A RAIN SHOWER FOR THE EASTERN THUMB/LAKE HURON SHORELINE. THE POTENTIAL MAY HINGE ON MORE OF A DRIZZLE/WEAK STRATIFORM RAIN POTENTIAL WITH VERY WEAK LAPSE RATE STRUCTURES FORECASTED. && .LONG TERM...MONDAY THROUGH SATURDAY DEEP LAYER N-NE FLOW WILL PERSIST ACROSS SE MI ON MONDAY AS THE FORECAST AREA WILL REMAIN UNDER THE INFLUENCE OF AN UPPER LOW AND ELONGATED TROUGH AXIS EXTENDING FROM NRN NEW ENGLAND ACROSS THE GREAT LAKES. A REGION OF MID LEVEL SUBSIDENCE WILL HOWEVER OVERSPREAD THE FORECAST AREA MON AFTERNOON IN THE WAKE OF A MID LEVEL SHORT WAVE IMPULSE DROPPING SOUTH ACROSS ERN LOWER MI. WHILE SOME DEGREE OF LOW-MID LEVEL MOISTURE WILL CONTINUE TO STREAM INTO SE MI FROM THE NORTHEAST...MID LEVEL WARMING WILL LIMIT CONVECTIVE CLOUD DEPTHS. THIS WILL SUPPORT A DRY AFTERNOON FORECAST...ALTHOUGH THERE IS LIKELY TO BE A HEALTHY CU/STRATO CU FIELD. THE CONTINUED NORTHERLY FLOW AND DAYTIME CLOUD COVER WILL KEEP MONDAY HIGHS IN THE 50S. A HIGH AMPLITUDE MID LEVEL RIDGE WILL THEN BUILD INTO LOWER MI ON TUES. THE LOSS OF THE NORTHERLY WIND COMPONENT AS SFC HIGH NUDGES INTO THE AREA FROM THE WEST AND BETTER DIURNAL HEATING POTENTIAL WILL SUPPORT TUES HIGHS INTO THE LOW 60S AFTER RELATIVELY CHILLY EARLY MORNING TEMPS IN THE 30S. THE 00Z GFS HAS TRENDED STRONGER WITH MID LEVEL SHORT WAVE ENERGY DROPPING INTO THE GREAT LAKES FROM CENTRAL CANADA IN THE WED-THURS TIME FRAME AND ACTUALLY DEVELOPS A CUT OFF CIRCULATION OVER LOWER MI WED NIGHT. THE 00Z ECMWF /WHOSE SOLUTION FOR THE WED-THURS TIME FRAME HAS BEEN BY FAR MORE CONSISTENT/ IS ALONG A SIMILAR LINE ALTHOUGH NOT NEARLY AS DEEP AS THE GFS. A DRY FORECAST WILL BE MAINTAINED IN THE WED-THURS TIME FRAME WITH CONTINUED MODEL DISCREPANCIES AND IN CONSIDERATION OF THE OVERALL DRY AIRMASS RESIDING OVER THE GREAT LAKES. IN LIGHT OF THE TRENDS...HIGH TEMPS FOR THURS HAVE BEEN NUDGED DOWN A FEW DEGREES /UPPER 50S TO LOW 60S/. THE DEPARTURE OF THIS SYSTEM LATE IN THE WEEK WILL THEN OFFER AN OPPORTUNITY FOR A SUBSTANTIAL WARMING TREND HEADING INTO NEXT WEEKEND AS MID LEVEL HEIGHTS REBOUND ACROSS THE REGION. && .MARINE... PERSISTENT LOW PRESSURE ALONG THE EAST COAST AND STRENGTHENING HIGH PRESSURE BUILDING ACROSS THE WESTERN GREAT LAKES TODAY INTO TONIGHT WILL ACTUALLY STRENGTHEN THE N-NW GRADIENT ACROSS LAKES HURON AND ERIE TODAY INTO TONIGHT. THE NET RESULT WILL BE A STRENGTHENING OF THE N-NW WINDS THIS AFTERNOON THROUGH TONIGHT. WINDS AND WAVES WILL THEN SLOWLY DECREASE MONDAY INTO TUESDAY MORNING AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST. && .AVIATION...ISSUED 1155 PM EDT SAT APR 25 2015 SOUTHEAST MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF DRY NORTHEASTERLY FLOW TONIGHT AS WEAK SURFACE RIDGING BUILDS IN. THIS WILL ENSURE A MOSTLY CLEAR SKY BELOW 10K FT THROUGH THIS TIME. PERSISTENT NORTHERLY FLOW WILL RETAIN VFR CONDITIONS THROUGHOUT SUNDAY. A POCKET OF MOISTURE ROTATING THROUGH THE RIDGE PERIPHERY WILL LEAD TO AN INCREASE IN DIURNAL STRATOCU BY EARLY AFTERNOON. //DTW THRESHOLD PROBABILITIES... * LOW IN CEILINGS AT OR BELOW 5000 FEET SUNDAY AFTERNOON AND EVENING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......SC AVIATION.....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 270722 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 322 AM EDT MON APR 27 2015 .SHORT TERM...TODAY AND TONIGHT EARLY MORNING US/CANADIAN RADAR COMPOSITE LOOP HAS BEEN SHOWING A REGION OF SHOWERS ADVANCING ACROSS LAKE HURON AND THE THUMB. THESE SHOWERS ARE ASSOCIATED WITH A COMPACT MID LEVEL SHORT WAVE NOW DROPPING INTO LAKE HURON FROM THE NORTHEAST. THE MAIN RIBBON OF LARGE SCALE ASCENT VIA GOOD DCVA WILL PRECEDE THE WAVE...WHICH IS FORECAST TO ROTATE ACROSS SE MI DURING THE COURSE OF THE MORNING. THE ASSOCIATED MID LEVEL COLD POOL AND RESULTANT STEEP MID LEVEL LAPSE RATES WILL DROP SOUTH ACROSS THE THUMB AND POINTS EAST THIS MORNING. THIS IS ALSO WHERE THE POOL OF DEEPER MOISTURE WILL RESIDE. THUS THE GREATER COVERAGE OF EARLY MORNING SHOWERS WILL REMAIN ACROSS THE THUMB INTO THE NORTHEASTERN DETROIT SUBURBS...WITH COVERAGE DECREASING TO THE WEST. ANY HIGHER INTENSITY RAIN SHOWERS THIS MORNING WILL BE VERY BRIEF...SO OVERALL QPF AMOUNTS ARE EXPECTED TO ONLY BE A FEW HUNDREDTHS OF AN INCH OR LESS. A MID LEVEL SUBSIDENCE BUBBLE WILL THEN SPREAD ACROSS SE MI THIS AFTERNOON IN THE WAKE OF THIS SHORT WAVE. THE CORRESPONDING MID LEVEL WARMING WILL REDUCE THE AFTERNOON CONVECTIVE CLOUD DEPTHS SUBSTANTIALLY AND SUPPORTS THE CURRENT DRY FORECAST. SE MI WILL REMAIN ON THE WESTERN EDGE OF A BROAD REGION OF LOW LEVEL CYCLONIC FLOW EXTENDING ALL THE WAY TO NEW ENGLAND. UPSTREAM SATELLITE AND SFC OBSERVATIONS TO THE NORTHEAST OF LAKE HURON SUGGEST AMPLE LOW LEVEL MOISTURE WILL REMAIN IN PLACE TODAY...WHICH WILL EVOLVE INTO A FAIRLY EXTENSIVE STRATO CU FIELD UNDER THE MID LEVEL INVERSION THIS AFTERNOON. DESPITE THE EXPECTED CLOUD COVER...NAM AND RAP SOUNDINGS STILL SUGGEST STEEPENING LOW LEVEL LAPSE RATES AND RISING MIXING DEPTHS DURING THE AFTERNOON WILL SUPPORT HIGHS WELL INTO THE 50S. NORTHERLY WINDS OFF LAKE HURON WILL AGAIN KEEP THE SHORELINE LOCALS SEVERAL DEGREES COOLER. LOW LEVEL CYCLONIC FLOW WILL EASE ITS GRIP ON SE MI TONIGHT AS HIGH PRESSURE NUDGES INTO LOWER MI FROM THE WEST. ANOTHER MID LEVEL SHORT WAVE /ALBEIT MUCH WEAKER/ WILL SLIDE SOUTH ACROSS ERN LOWER MI TONIGHT WITHIN THE PERSISTENT MID LEVEL CYCLONIC FLOW. THIS FEATURE WILL LIKELY JUST LEAD TO SOME PERIODIC MID CLOUDS. MODEL RH PROGS DO HOWEVER SUGGEST THE EROSION OF THE DIURNALLY ENHANCED CU FIELD WILL TAKE WELL INTO THE NIGHT...LIKELY A RESULT OF THE PERSISTENT INVERSION. THESE FACTORS WILL SUPPORT LEANING ON THE HIGH END OF MOS GUIDANCE FOR MIN TEMPS /RANGING FROM THE MID 30S IN THE THUMB TO LOW 40S IN METRO DETROIT/. && .LONG TERM...TUESDAY THROUGH SUNDAY A MORE COMFORTABLE STRETCH OF SPRING WEATHER IS EXPECTED TUESDAY AND WEDNESDAY WITH PREDOMINATELY DRY CONDITIONS AND MODERATING TEMEPRATURES. PERSISTENT STRATOCUMULUS SHOULD LET UP BRIEFLY AT THE START OF THE PERIOD TUESDAY WITH TWO GOOD SURGES OF SUBSIDENCE AND A FAIRLY RAPID LOSS IN DEEP CYCLONIC FLOW. THIS LOSS IN LOW CLOUD SHOULD ONLY BE TEMPRORARY AS A GOOD SIGNAL EXISTS THAT LOW LEVEL RESIDUAL MOISTURE WILL THEN BLOSSOM INTO A FAIRLY ROBUST DIURNAL CU RESPONSE. HIGHS ON TUESDAY ARE EXPECTED TO CLIMB A COUPLE OF DEGREES ABOVE 60...ALTHOUGH AREAS HUGGING THE LAKESHORE WILL BE A FEW DEGREES COOLER. MUDDY MID TO UPPER LEVEL RIDGING AND LACK OF FLOW IN THE COLUMN WILL LEAD TO PERSISTENCE FOR WEDNESDAY. THE LOW LEVELS ARE FORECASTED TO BE MARGINALLY DRIER WHILE THERE IS SOME SIGNAL FOR SOME MIDLEVEL MOISTURE TO POOL OVER LOWER MICHIGAN AHEAD OF THE NEXT SHORTWAVE. STILL EXPECTING SOME MIDCLOUD...BUT BETTER LOW LEVEL LAPSE RATES SHOULD SUPPORT HIGHS IN THE MIDDLE 60S ON WEDNESDAY. MODEL DATA IS AGGRESIVE WITH AN UPPER LEVEL ENERGY/VORTICITY MAXIMUM DROPPING STRAIGHT SOUTHWARD INTO THE LAKE MICHIGAN VICINITY WEDNESDAY NIGHT AND THURSDAY. THE BOOK HASNT BEEN WRITTEN YET ON SPECIFICS WITH MODELS TRENDING WESTERLY WITH THE QPF AXIS. REGARDLESS...FAIRLY ROBUST SHORTWAVE AND INBOUND TRAJECTORY OF AIR PARCELS SUPPORT AN INCREASINGLY GOOD POTENTIAL FOR A COOL DOWN AND RAIN SHOWERS WEDNESDAY NIGHT AND THURSDAY. BUMPED POPS UPWARD FROM THE OFFERED GRIDDED GUIDANCE. TEMPERATURES THURSDAY COULD STRUGGLE TO CLIMB INTO THE 50S...ESPECIALLY ACROSS THE NORTHERN CWA. && .MARINE... NORTHERLY FLOW WILL WEAKEN WITH TIME TODAY AS THE MIDLEVEL TROUGH AXIS SWINGS SOUTHWARD AWAY FROM THE STATE. A RIDGE OF SURFACE HIGH PRESSURE WILL THEN BUILD INTO THE STATE...ESPECIALLY TONIGHT. THIS AREA OF HIGH PRESSURE IS EXPECTED TO YIELD A RUN OF WEAK WINDS OVER THE MARINE AREAS TUESDAY AND WEDNESDAY. A NEXT SURGE IN NORTHERLY WINDS IS EXPECTED TO DEVELOP ON THURSDAY IN THE WAKE OF A WEAK SURFACE LOW OR TROUGH AXIS. && .AVIATION...ISSUED 104 AM EDT MON APR 27 2015 SOLID CLOUD SHIELD IS MAKE STEADY PROGRESS SOUTHWARD ACROSS THE AREA. CEILING WILL LOWER AS A SECOND SURGE OF LOWER LEVEL MOISTURE ARRIVES IN THE PRE-DAWN HOURS. A FEW LIGHT SHOWERS MAY SPROUT DURING THE MORNING HOURS. OTHERWISE...CEILINGS ARE EXPECTED TO LIFT THROUGH THE MIDDAY HOURS AS DRIER AIR INFILTRATES IN THE NEAR SURFACE LAYER. WINDS WILL REMAIN MAINLY FROM THE NORTH. //DTW THRESHOLD PROBABILITIES... * HIGH CONFIDENCE IN CIGS BELOW 5000 FT AFTER 10Z TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR LHZ421- 441>443. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SC LONG TERM....CB MARINE.......CB AVIATION.....MANN YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 022039 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 339 PM EST SAT JAN 2 2016 .DISCUSSION... THE 12Z DTX SOUNDING REVEALED SATURATION AROUND 850 MB LEVEL...BUT DRIER AIR/EXPANDING DEW PT DEPRESSIONS QUICKLY ACCELERATING TOWARD THE GROUND. MODELS FROM YESTERDAY WERE TOO MOIST...AND THUS NO HINT OF DRIZZLE ANYWHERE THIS MORNING. STRONG WARM ADVECTION AHEAD OF A COLD FRONT TONIGHT HAS ALLOWED LOW CLOUDS TO PEEL OFF LAKE MICHIGAN AND DISSIPATE OVER SOUTHERN LOWER MICHIGAN. CLOUDS SHOULD FILL BACK IN TONIGHT AS GOOD SHOT OF COLD ADVECTION OCCURS BEHIND TONIGHTS FRONTAL PASSAGE...AS 850 MB TEMPS SLIGHTLY ABOVE ZERO AT 00Z PLUMMET TO -10 C AT 12Z SUNDAY. CLOUD DEPTHS DO NOT EXTEND MUCH ABOVE THIS LEVEL...PER SOUNDINGS...AND THUS IT LOOKS TO BE A STRUGGLE TO GENERATE ANY SNOW SHOWER ACTIVITY...EVEN WITH FAVORABLE LOW LEVEL CONVERGENCE/CYCLONIC FLOW. STRONGER SECONDARY TROUGH/COLD SURGE ON TARGET TO PASS THROUGH SOUTHEAST MICHIGAN SUNDAY NIGHT...AS TEMPS OF -24 TO -26 C AT 700 MB SWINGS THROUGH. CERTAINTY BETTER CHANCE FOR SNOW SHOWERS IN THE SUNDAY NIGHT-MONDAY TIME FRAME...AS NORTHERLY WINDS COME ACROSS LAKE HURON. BUT STRONG SUBSIDENCE TAKING PLACE ON MONDAY BEHIND THE UPPER WAVE/TROUGH WILL TEND TO UNDERCUT THE ACTIVITY...DESPITE THE GOOD LAKE HURON INSTABILITY WITH 850 MB TEMPS STILL ADVERTISED AROUND -20 C. STILL...CONFIDENCE IS HIGH THERE WILL BE A GOOD COVERAGE OF SNOW SHOWERS PUSHING WEST DURING MONDAY...WITH MAINLY LIGHT ACCUMULATIONS AS FAILURE TO SET UP DOMINATE BAND AND WHAT LOOKS TO BE TRANSIENT NATURE OF ACTIVITY. PORT HURON AREA WILL STILL HAVE TOO BE WATCHED CLOSELY FOR HEAVIER ACTIVITY WITH LONGER FETCH POTENTIALLY SETTING UP LATE SUNDAY NIGHT/MONDAY MORNING. LARGE ANTICYCLONE SPREADING INTO LOWER MICHIGAN LATE IN THE DAY...WHICH WILL LEAD TO EVEN LOWER INVERSION HEIGHTS...ALONG WITH OFFSHORE WINDS DEVELOPING BY EVENING....ENDING ACTIVITY. QUESTION ON MONDAY IS IF TEMPERATURES WILL REMAIN BELOW 20 DEGREES WITH THE VERY COLD AIRMASS...AS 925 MB TEMPS ADVERTISED TO HOVER -13 C. WITH LIMITED TO NO SNOW COVER OVER SOUTHEAST MICHIGAN AND SOME MODIFICATION OF THE AIRMASS COMING OVER LAKE HURON...PREFER TO KEEP MAXES AT OR ABOVE 20 DEGREES. REGARDLESS...MONDAY NIGHT WILL BE VERY COLD WITH MOSTLY CLEAR SKIES SETTING IN AND FAVORABLE RADIATING CONDITIONS ALLOWING MINS TO DROP INTO THE 5 TO 15 DEGREE RANGE...WITH POTENTIAL TO SHAVE 5 DEGREES OFF THOSE READINGS IF SNOW ACCUMULATIONS ARE MORE EXTENSIVE THAN CURRENTLY FORECAST. STRONG HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY...AND SLOWLY DRIFT EASTWARD THROUGH THE REMAINDER OF THE WEEK. THIS HIGH WILL FILTER IN COOLER TEMPERATURES AND DRY CONDITIONS THROUGH THURSDAY. THE COLDEST DAY WILL BE ON TUESDAY WHEN THE HIGH WILL ONLY BE IN THE MID 20S AND TUESDAY NIGHTS LOW WILL BE IN THE UPPER TEENS. TEMPERATURES WILL REMAIN COOLER BUT SLOWLY INCREASE THROUGH THURSDAY. THE NEXT CHANCE FOR RAIN/SNOW SHOWERS ARRIVES ON FRIDAY AND INTO SATURDAY. HOWEVER...THERE IS STILL SOME DISAGREEMENT IN THE TIMING OF THE LOW PRESSURE SYSTEM SO ONLY PUT IN HIGH CHANCE POPS INTO THE FORECAST FOR NOW. && .MARINE... WINDS WILL REMAIN ELEVATED THROUGH THE REMAINDER OF THE WEEKEND AS AN AREA OF LOW PRESSURE DROPPING INTO SOUTHERN ONTARIO SENDS A COUPLE COLD FRONTS THROUGH THE GREAT LAKES. CURRENT SOUTHWEST WINDS GUSTING TO 25 KNOTS WILL VEER TO THE NORTHWEST LATE TONIGHT BEHIND THE FIRST FRONT. COLDER AIR BEHIND THE FRONT WILL KEEP UNSTABLE CONDITIONS AND GUSTY WINDS OVER THE LAKES. A FEW GUSTS TO GALES WILL BE POSSIBLE BUT NOT LIKELY TO BE LONG LIVED OR WIDESPREAD AT THIS TIME. A SECOND FRONT WILL WORK THROUGH SUNDAY NIGHT VEERING WINDS TO THE NORTH/NORTHEAST. THOUGH WINDS MAY RELAX A BIT...THE NORTHERLY FETCH WILL SEND ELEVATED WAVES INTO THE NEARSHORE ZONES AROUND THE THUMB LEADING TO CONTINUED SMALL CRAFT CONDITIONS. HIGH PRESSURE BUILDING INTO THE REGION WILL ALLOW BOTH WIND AND WAVE CONDITIONS TO DIMINISH BY MONDAY NIGHT AND TUESDAY. && .AVIATION...ISSUED 1251 PM EST SAT JAN 2 2016 SUBSIDENCE IN THE WAKE OF THIS MORNINGS TROUGH PASSAGE IS RESULTING IN A GOOD DEAL OF DRY AIR AND BREAKS IN THE CLOUDS OVER LOWER MICHIGAN. EVEN WITH THE MODEL SOUNDINGS ADVERTISING A STRENGTHENING INVERSION...DECIDED TO INTRODUCE SCT CIGS THIS AFTERNOON AND INTO THE OVERNIGHT. THE NEXT FRONT WILL DROP THROUGH EARLY TONIGHT WHICH WILL BRING A RETURN OF MVFR...POSSIBLY IFR...CIGS. SOUTHWEST WINDS WILL INCREASE SOME THIS EVENING GUSTING TO AROUND 20 KNOTS AND WILL REMAIN ABOVE 10 KNOTS THROUGH THE FORECAST. FOR DTW...CIGS LOOK TO BE THE IMMEDIATE ISSUES AS BREAKS IN THE STRATUS ARE EXPANDING ACROSS LOWER MI. WENT SCT FOR SEVERAL HOURS THIS EVENING TAKING INTO ACCOUNT THE AMOUNT OF DRY AIR UPSTREAM. CIGS WILL DROP OVERNIGHT WITH ANOTHER COLD FRONTAL PASSAGE. //DTW THRESHOLD PROBABILITIES... * LOW IN CEILINGS BELOW 5000 FT THIS EVENING...HIGH FOR OVERNIGHT AND SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LHZ442- 443. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LHZ422. SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LHZ421-441. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ DISCUSSION...SF/RK MARINE.......DRK AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 061959 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 259 PM EST FRI NOV 6 2015 .SHORT TERM...TONIGHT WESTERLY LOW LEVEL COLD ADVECTION WILL CONTINUE THROUGH TONIGHT...ALBEIT AT SLOWER PACE AS WINDS DIE DOWN. 12Z GRB SOUNDING REVEALED 850 MB TEMP OF -1 C...WHICH LOOKS TO BE OUR TARGET READING BY 12Z SATURDAY...IF NOT SLIGHTLY COLDER. LOW CLOUDS (2-3 FT) TRAPPED UNDERNEATH SUBSIDENCE INVERSION WILL PERSIST FOR MUCH OF THE NIGHT...AS THEY CURRENTLY EXTEND BACK ACROSS THE WESTERN GREAT LAKES. LARGE SCALE/POSITIVE TILTED UPPER LEVEL TROUGH WILL PUSH INTO THE CENTRAL GREAT LAKES AROUND 12Z SATURDAY...WHICH SHOULD HELP WEAKEN THE INVERSION AND ALLOW FOR CLOUDS TO BREAK UP...ALTHOUGH CONFIDENCE IS NOT TERRIBLY HIGH IN THIS SCENARIO. IF CLOUDS HOLD WE WILL LIKELY SEE MINS AROUND 40 DEGREES...OTHERWISE LATE NIGHT CLEARING WILL ALLOW FOR TEMPERATURES TO DIP INTO THE 30S. && .LONG TERM...SATURDAY THROUGH NEXT FRIDAY MID LEVEL TROUGHING ACROSS THE GREAT LAKES ON SATURDAY WILL BE REINFORCED BY A MID LEVEL SHORT WAVE IMPULSE RAPIDLY DROPPING INTO THE AREA FROM CENTRAL CANADA. THE NAM SOLUTION IS ON THE STRONGER SIDE OF THE 12Z MODEL SUITE...WHICH RESULTS IN A LITTLE COOLER MID LEVEL TEMPS. THE RESULT BEING THAT THE NAM SUGGESTS MUCH BETTER CONVECTIVE CLOUD DEPTHS SAT AFTERNOON AND THUS A BETTER POTENTIAL FOR SOME DAYTIME SHOWERS IN COMPARISON TO THE GFS/ECMWF/CANADIAN. THIS WAVE HAS STILL NOT BEEN SAMPLED WELL BY THE 12Z MODEL SUITE. GIVEN THE UNCERTAINTY...A LOW CHANCE OF AFTERNOON SHOWERS WILL BE WARRANTED. STEEPENING OF THE LWO LEVEL LAPSE RATES WILL BOOST THE DAYTIME MIXED LAYER ENOUGH TO SUPPORT HIGH TEMPS IN THE LOW 50S UNDER BREEZY WESTERLY WINDS. A REINFORCING SHOT OF COLDER AIR WILL ARRIVE IN THE WAKE OF THIS SHORT WAVE /850MB TEMPS DROPPING TO -5C/ SAT NIGHT. MID LEVEL SUBSIDENCE AMIDST CONFLUENT FLOW ALOFT AND BUILDING SFC HIGH PRESSURE SHOULD SUPPORT A CLEARING TREND. THE GRADIENT WILL RELAX LATE BUT WILL STILL OFFER AN OPORTUNITY FOR THE BOUNDARY LAYER TO DECOUPLE...SUPPORTING FCST MIN TEMPS DOWN INTO THE 20S SAT NIGHT OUTSIDE OF THE DETROIT URBAN AREA. HIGH PRESSURE WILL SLIDE FROM THE OHIO VALLEY SUNDAY TO THE MID ATLANTIC MONDAY AS MID LEVEL HEIGHTS BUILD ACROSS THE GREAT LAKES. AN ABUNDANCE OF DRY AIR SHOULD SUPPORT MAINLY CLEAR CONDITIONS ACROSS SE MI THROUGH THIS PERIOD. THE DEVELOPMENT OF A LIGHT S-SW FLOW WILL PROVIDE A SLIGHT WARMING TREND FROM THE SEASONALLY COOL TEMPS ON SUNDAY TO NEAR AVERAGE HIGHS BY MONDAY. HIGH UNCERTAINTY FOR THE MIDDLE OF NEXT WEEK TIED TO THE PROGRESSION OF A DEEP UPPER TROUGH NOW EVIDENT ON WATER VAPOR IMAGERY IN THE GULF OF ALASKA. 12Z DETERMINISTIC GFS/EURO ARE CERTAINLY IMPRESSIVE WITH THEIR DEPICTION OF INTENSE CYCLOGENESIS OVER THE WESTERN GREAT LAKES REGION. IF THIS WERE TO VERIFY IT WOULD RESULT IN A WET AND WINDY PERIOD TUESDAY NIGHT THROUGH THURSDAY. A COUPLE OF REASONS TO TEMPER EXPECTATIONS AT THIS POINT: 1) RUN-TO-RUN CONTINUITY HAS BEEN POOR...AND 2) GEFS MEMBERS ARE WIDELY SPREAD WITH RESPECT TO POSITION AND STRENGTH OF THE POTENTIAL STORM. FELT THAT IT WAS PRUDENT TO BACK OFF OF SUPERBLEND LIKELY POPS FOR WEDNESDAY NIGHT AND WENT WITH BROAD CHANCE POPS DURING THE AFOREMENTIONED TIME FRAME TO HIGHLIGHT PRECIP POTENTIAL. && .MARINE... THE MARINE HEADLINES WILL BE CANCELLED WITH THE AFTERNOON FORECAST PACKAGE AS WINDS AND WAVES MAKE A STEADY DECLINE DURING THE EVENING AS THE GRADIENT WEAKENS. WESTERLY WINDS WILL THE INCREASE OVERNIGHT INTO THE DAY SATURDAY AHEAD OF A COLD FRONT MOVING INTO THE NORTHERN GREAT LAKES. THIS FRONT WILL PUSH ACROSS LAKES HURON AND ERIE LATE SATURDAY LEADING TO AN INCREASE IN WIND SPEEDS AS COLDER AIR ADVANCES ACROSS THE REGION. HIGH PRESSURE WILL FORECAST TO BUILD ACROSS THE OHIO VALLEY ON SUNDAY WILL DECREASE THE WINDS AND WAVES. A SUBTLE INCREASE IN SOUTHWESTERLY WINDS WILL THEN DEVELOP BY MONDAY WITHIN THE RETURN FLOW OF THIS SURFACE HIGH. && .AVIATION...ISSUED 1225 PM EST FRI NOV 6 2015 WESTERLY COLD ADVECTION BEHIND THIS MORNINGS COLD FRONT WILL ALLOW FOR CONTINUED GUSTY WINDS THIS AFTERNOON HOURS...BUT GRADUALLY COMING DOWN FROM THE PEAKS AROUND 30 KNOTS. HIGH MVFR CLOUD DECK TRAPPED UNDERNEATH INVERSION WILL PERSIST INTO TONIGHT. CURRENT INDICATIONS ARE CLOUDS WILL ATTEMPT TO CLEAR OUT AROUND SUNRISE. IF THIS IS THE CASE...A REDEVELOPMENT OF LOW VFR CLOUDS WILL OCCUR WITH DAYTIME HEATING STEEPENING UP LOW LEVEL LAPSE RATES. WINDS WILL BECOME GUSTY WESTERLY WITH THE BETTER MIXING ONCE AGAIN...AND LOOKS LIKE PEAKS OF 25 KNOTS CAN BE EXPECTED. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILINGS AOB 5KFT THROUGH TONIGHT. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LHZ421-422- 441>443. LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LEZ444. && $$ SHORT TERM...SF LONG TERM....SC/DT MARINE.......SC AVIATION.....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 110801 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 401 AM EDT FRI SEP 11 2015 .SHORT TERM...TODAY AND TONIGHT A SOUTHERN DRIFT TO THE PARENT POTENTIAL VORTICITY ANOMALY OVER CENTRAL CANADA AND A NUMBER OF UPPER LEVEL JET MAXIMA WORKING THROUGH THE POLAR JET STREAM WILL ALLOW FOR THE DEVELOPMENT OF A FULL LATITUDE TROUGH OVER EASTERN NORTH AMERICA TODAY AND TONIGHT. THE MAIN FEATURE OF NOTE FOR THE WEATHER ACROSS SEMICH THE NEXT 12 HOURS WILL BE A JET STREAK THAT IS NOW BEGINNING TO EMERGE OUT OF THE TRAILING TROUGH AXIS BASE OVER SECTIONS OF IA/IL/WI. MORE SPECIFICALLY...PRECIPITATION CHANCES ACROSS MUCH OF SEMICH TODAY WILL BE HEAVILY DEPENDENT UPON THE RIGHT ENTRANCE REGION DYNAMICS FROM THIS EMERGING JET MAXIMUM. UPSTREAM CONVECTION AND THUNDERSTORM ACTIVITY LAST EVENING WAS ABLE TO CONSOLIDATE WITHIN THE JUXTAPOSITIONING OF THE CONVERGENCE IMMEDIATELY PRECEDING THE TROUGH AXIS AND WITHIN GEOPOTENTIAL HEIGHT FALLS MAX. DOWNSCALING PROCESSES WERE ABLE TO TAKE OVER WITH MUCH OF THE DYNAMICAL SUPPORT TRANSITIONING IN THE MESOSCALE TO A MCV OVER CENTRAL MO. TO THE NORTHEAST OF THIS FEATURE A WEAK MIDLEVEL DEFORMATION AXIS IS DRAPED THROUGH NORTHERN IL AND THROUGH PORTIONS OF SOUTHEASTERN MICHIGAN INCLUDING THE THUMB. THE SPORADIC SHOWERS THAT HAVE BEEN ABLE TO PERSIST OVER HURON COUNTY TONIGHT APPEARS TO HAVE SOME SUPPORT FROM THIS WEAK DEFORMATION. MODEL DATA SUGGESTS RIGHT ENTRANCE REGION DYNAMICS TO DEVELOP OVER PORTIONS OF NO ILLINOIS THIS MORNING AS THE JET STREAK LIFTS TO THE NORTHEAST. THIS APPEARS TO BE OCCURRING AS SHOWERS EXPAND EASTWARD AND AN UPTICK IN CONVECTION HAS TAKEN PLACE. NWP SOLUTIONS SUPPORT A FAIRLY RAPID ACCELERATION OF THE JET MAX TO THE NORTHEAST...ONLY IMPACTING SOUTHEASTERN MICHIGAN DURING THE MIDDAY PERIOD. THE LOW LEVEL CONVERGENCE THAT ARISES AND DCVA FROM APPROACHING TROUGH IS THE EXTENT OF THE FORCING FOR ASCENT. AN ANALYSIS OF FORECASTED SYSTEM RELATIVE ISENTROPIC DOESN/T OFFER MUCH WITH DEEP SYSTEM RELATIVE ISENTROPIC DOWNGLIDE EXPECTED. THE RECENT TREND OF THE CAMS AND DETERMINISTIC SOLUTIONS HAS BEEN ONE OF A SOUTHERN SHIFT IN PRECIPITATION ACTIVITY. QUALITATIVELY THIS IS REASONABLE CONSIDERING THE POTENTIAL FOR A FLATTER EJECTION OF MIDLEVEL FGEN FORCING WITH THE MCV OR MO. FORECAST CHANGES THIS ISSUANCE WAS TO SHIFT PRECIPITATION CHANCES TO THE SOUTH WHILE LOWERING POPS INTO THE CHANCE CATEGORY. BEST TIME WINDOW FOR SHOWERS TODAY WILL BE BETWEEN 15-23Z. QPF AMOUNTS OF AROUND .1 OF AN INCH WILL BE POSSIBLE. FOR TONIGHT...MODEL DATA SUPPORTS A GOOD MIX OF INGREDIENTS WHICH WILL LEAD TO A LAKE AGGREGATE SURFACE TROUGH OVER PORTIONS OF MID LAKE HURON. GIVEN STRUCTURE AND ORIENTATION OF THE THE UPPER LEVEL JET AXIS AND ABSOLUTE VORTICITY OVERHEAD...THIS SURFACE TROUGH IS EXPECTED TO REMAIN OFFSHORE OF THE THUMB THROUGH THE END OF THE PERIOD. EXPECT MUCH OF THE DEVELOPING LAKE EFFECT SHOWER ACTIVITY TO REMAIN TIED TO THIS FEATURE. WENT COOLER WITH MINS TONIGHT...TEMPERATURES DIPPING INTO THE 40S FOR MANY AREAS. && .LONG TERM...SATURDAY THROUGH THURSDAY TEMPERATURES THIS WEEKEND WILL BE IN STARK CONTRAST TO THOSE OF LAST WEEKEND AS LONG WAVE TROUGH AMPLIFICATION ACROSS THE ERN US ALLOWS COOL AIR FROM CENTRAL CANADA TO INFILTRATE THE GREAT LAKES. THIS WILL SUPPORT TEMPS BELOW MID SEPTEMBER AVERAGES. A MID LEVEL SHORT WAVE NOTED IN THE LATEST WATER VAPOR LOOP OVER NRN MANITOBA IS FORECAST TO DROP INTO THE MID MS VALLEY ON SATURDAY BEFORE PLUNGING ACROSS THE TN VALLEY INTO THE CAROLINAS SAT NIGHT INTO SUNDAY. THE ASSOCIATED CORE OF COLDEST MID LEVEL TEMPS WILL IN TURN SLIDE SOUTH OF THE FORECAST AREA. MODEL SOUNDINGS DO HOWEVER SUGGEST CONVECTIVE CLOUD DEPTHS WILL BE ENOUGH TO SUPPORT A CHANCE OF SHOWERS ON SATURDAY...ESPECIALLY DURING THE PEAK IN THE DIURNAL HEATING CYCLE. THE ENHANCED HEAT AND MOISTURE FLUX OFF LAKE HURON UNDER LOW LEVEL COLD AIR ADVECTION DURING THE COURSE OF THE DAY SAT /850MB TEMPS DROPPING INTO THE LOW SINGLE DIGITS/ WILL BOOST EQUILIBRIUM LEVELS OVER THE LAKE AND SUPPORT LAKE EFFECT RAIN SHOWERS. THE NORTHERLY FLOW DURING THE DAY WILL ENHANCE THE CHANCES FOR SOME LAKE MODIFIED SHOWERS TO WORK INLAND...ESPECIALLY ACROSS THE THUMB. THE DEGREE OF LOW LEVEL COLD AIR AND EXPECTED CLOUD COVER WILL SUPPORT FCST HIGHS ONLY IN THE UPPER 50S TO MID 60S SAT AFTN. THE LOSS IN DIURNAL HEATING AND FCST BACKING OF THE LOW LEVEL WINDS TOWARD THE NORTHWEST WILL REDUCE THE CHANCES OF SHOWERS SAT NIGHT. GIVEN THE COLD AIR...SUSPECT THERE WILL BE SOME LAKE AGGREGATE TROUGHING ACROSS THE REGION. THIS AND THE EXPECTED INVERSION DEPTH MAY SUSTAIN A FAIR AMOUNT OF CLOUDS WELL INTO SAT NIGHT...WARRANTED FCST MINS ON THE HIGH END OF GUIDANCE /MID 40S TO AROUND 50/. EVOLUTION OF THE ERN US LONG WAVE TROUGH INTO A CLOSED MID LEVEL CIRCULATION /CENTERED OVER THE UPPER OH VALLEY AND ERN GREAT LAKES/ IS SHOWN BY THE 00Z MODEL SUITE ON SUNDAY. MODEL SOLUTIONS SUGGEST THE BETTER MOISTURE WILL REMAIN EAST OF THE FORECAST AREA. SFC HIGH PRESSURE BUILDING OVER THE MID MS/LOWER OH VALLEY WILL FORCE A MORE NORTHWESTERLY LOW LEVEL WIND FIELD OVER LOWER MI...FORCING ANY LAKE ENHANCEMENT INTO ONTARIO. A SLOW DEPARTURE OF THE UPPER LOW TOWARD THE EAST DURING THE DAY SUNDAY WILL CAUSE SLIGHT MID LEVEL WARMING. PER MODEL SOUNDINGS...THIS WILL BE ENOUGH TO LIMIT CONVECTIVE CLOUD DEPTHS AND THUS KEEP PRECIP CHANCES FAIRLY LOW. LINGERING LOW LEVEL THERMAL TROUGHING AND DIURNAL CLOUD COVER WILL STILL ONLY SUPPORT FCST HIGH TEMPS IN THE 60S. THE UPPER LOW IS FCST TO REMAIN RATHER PROGRESSIVE PER LATEST MEDIUM RANGE SOLUTIONS. FCST LONG WAVE TROUGH AMPLIFICATION ACROSS THE PACIFIC NORTHWEST NEXT WEEK WILL LEAD TO BUILDING HEIGHTS ACROSS THE CNTL AND ERN US. THIS WILL RESULT IN A STEADY WARMING TREND MON INTO THURS. && .MARINE... COLD AIR ADVECTION WILL BE ONGOING DURING THE COURSE OF THE DAY AND INTO TONIGHT. THIS WILL RESULT IN INCREASINGLY UNSTABLE CONDITIONS ACROSS THE GREAT LAKES. THIS AND AN INCREASING NORTHERLY GRADIENT WILL CAUSE STRENGTHENING WINDS...ESPECIALLY THIS AFTERNOON INTO EVENING. THIS WILL CAUSE RATHER ROUGH BOATING CONDITIONS TO DEVELOP. THE GUSTY WINDS WILL PERSIST THROUGH TONIGHT INTO SUNDAY. IN ADDITION TO THE INCREASING WINDS AND WAVES...THIS INSTABILITY WILL RESULT IN A CHANCE OF WATERSPOUTS ACROSS ALL OF THE LAKES. THE GRADIENT WILL WEAKEN SAT NIGHT INTO SUNDAY ALLOWING WINDS AND WAVES TO DECREASE. THE RISK FOR WATERSPOUTS WILL HOWEVER PERSIST INTO THE DAY SUNDAY BEFORE WARMER AIR BEGINS TO PUSH BACK INTO THE REGION EARLY NEXT WEEK. && .AVIATION...ISSUED 1210 AM EDT FRI SEP 11 2015 A DIFFUSE COLD FRONT WILL CONTINUE TO MOVE SLOWLY THROUGH SE MICHIGAN AND SUPPORT THE CHANCE OF A PASSING SHOWER THROUGH THE EARLY MORNING. COVERAGE AND DURATION WILL BE TOO BRIEF TO INCLUDE IN THE FORECAST. LIGHT AND VARIABLE PREFRONTAL WIND WILL BECOME NORTHERLY WITH A MODEST INCREASE IN SPEED POST FRONT. THE FRONT WILL ALSO HAVE POTENTIAL TO SUPPORT MVFR CEILING WITH A NOCTURNAL PASSAGE THROUGH THE TERMINAL SITES...ALTHOUGH OBSERVATIONS UP TO PRESS TIME DID NOT SUPPORT AN AGGRESSIVE FORECAST. THIS ALSO PLAYS INTO THE IDEA THAT RAIN DEVELOPING LATE MORNING THROUGH EARLY FRIDAY EVENING WILL END UP VFR AS WELL. FOR DTW... LIGHT AND VARIABLE SURFACE WIND WILL INCREASE MODESTLY FROM A NORTHERLY DIRECTION TO MARK THE FRONTAL PASSAGE. THE POTENTIAL FOR MVFR CEILING WILL INCREASE AS THE FRONT ARRIVES AT DTW DURING THE A FAVORABLE TIME AROUND SUNRISE. CEILING WILL LIKELY MIX UP INTO VFR BUT REMAIN BELOW 5000 FT AS RAIN BEGINS DURING LATE MORNING. //DTW THRESHOLD PROBABILITIES... * MEDIUM FOR CEILING AOB 5000 FT AFTER 12Z FRIDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY FROM NOON TODAY TO MIDNIGHT EDT SATURDAY NIGHT FOR LHZ441>443. SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 8 PM EDT SATURDAY FOR LHZ421-422. LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 10 PM EDT SATURDAY FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 10 PM EDT SATURDAY FOR LEZ444. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......SC AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 120741 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 341 AM EDT SAT SEP 12 2015 .SHORT TERM...TODAY AND TONIGHT THE UPPER LEVEL TROUGH OVER MUCH OF EASTERN NORTH AMERICA CONTINUES TO AMPLIFY THIS MORNING AS THE FINAL COHERENT PV ANOMALY DIGS DOWN WITHIN THE BACKSIDE OF THE TROUGH. AN INTERESTING PATTERN WILL DEVELOP TODAY OVER SOUTHEASTERN MICHIGAN WITH STRONG MIDLEVEL CYCLONIC FLOW REMAINING IN PLACE WHILE SFC-LOW LEVEL TRAJECTORIES BECOME INCREASINGLY ANTICYLONIC. THIS CHANGE TO A WESTERLY DIRECTION WILL BE A RESPONSE...IN PART...TO THE SHARP HEIGHT RISES THAT WILL OCCUR IN THE WAKE OF THE AFOREMENTIONED STRONG VORTICITY MAXIMUM DIGGING SOUTHWARD. THE END RESULT...IS THAT PRECIPITATION POTENTIAL WILL BE DEPENDENT SOLELY ON MESOSCALE PROCESSES AND LOW LEVEL THERMODYNAMICS. THE MAIN SWATH OF FGEN AND DEFORMATION RAIN HAS SLID DECISIVELY TO THE EAST THIS MORNING. SOME ISOLATED PATCHES OF DRIZZLE OR SPRINKLES REMAIN OVER CENTRAL SECTIONS OF LOWER MICHIGAN...BUT COVERAGE SPARSE AS IT IS CONTINUES TO LESSEN. THERE DOES APPEARS TO BE SOME TERRAIN INFLUENCE ON THIS ACTIVITY. THE FEATURE OF NOTE TODAY BECOMES THE DEVELOPING LAKE AGGREGATE TROUGH OVER CENTRAL LAKE HURON. RECENT SURFACE WIND OBSERVATIONS SUPPORT SOME DIRECTIONAL CONVERGENCE AND SATELLITE IMAGERY DEPICTS A BURGEONING STRATOCUMULUS DECK. THIS IS DEVELOPING ON SCHEDULE. FOR TODAY...MODELS PUSH THIS AGGREGATE TROUGH AXIS SOUTHWARD WITH TIME...WITH SOME THERMODYNAMIC PROGS INCLUDING...LIFTING INDICES AND THETA E LAPSE RATES...SUGGESTING AN ADVECTION OF INSTABILITY DIRECTLY SOUTHWARD THROUGH THE CWA TODAY. THE INHERITED GRIDS HAVE THIS WELL IN HAND WITH A SCATTERED MENTION TODAY OF LIGHT RAIN SHOWERS AND A HEFTY SKY FRACTION. WITH THE TRANSITION TO ANTICYCLONIC FLOW...NOT EXPECTING A WIDESPREAD COVERAGE OR SIGNIFICANT QPF POTENTIAL. IN FACT...IT IS DIFFICULT TO FORECAST MUCH MORE THAN AN HUNDREDTH OR TWO AWAY FROM LAKE HURON. WITH CLOUDS...THE FORECAST RESIDES ON THE COOLER SIDE WITH LOWER 60S AREAWIDE. A NARRATIVE IS THE NORTHERLY WINDS AT/AROUND 15 MPH WHICH WILL BE NOTICEABLE GIVEN THE RECENT WARMTH. DEEP DRY AIR ADVECTION AND LOSS OF DIURNAL HEATING WILL END ANY LIGHT SHOWERS LEFT THIS EVENING. THE UPPER LEVEL TROUGH AXIS OR CLOSED HEIGHT ANOMALY WILL SLIDE OVER LAKE HURON TONIGHT. THIS SHOULD ALLOW A BAND OF LAKE EFFECT SHOWERS TO BECOME INCREASINGLY ORGANIZED AFTER MIDNIGHT TONIGHT. AT THIS TIME...BULK OF THIS ACTIVITY IS EXPECTED TO REMAIN EAST OF THE CWA. A CONTINUED NORTHERLY GRADIENT WIND APPEARS TO PUT A FLOOR ON THE TEMPERATURE RESPONSE TONIGHT. DID LOWER TEMPERATURES A COUPLE OF DEGREES WITH LOWER 40S OUTSIDE OF THE DETROIT URBAN HEAT ISLAND...AND EVEN UPPER 40S FOR THE DETROIT URBAN AREA. && .LONG TERM...SUNDAY THROUGH FRIDAY THE POSITION OF THE UPPER LOW SUN MORNING IS EXPECTED TO BE ACROSS THE UPPER OHIO VALLEY AND LAKE ERIE. THE 00Z MODEL SUITE INSIST THAT BUILDING HEIGHTS ACROSS THE WRN GREAT LAKES WILL FORCE THIS SYSTEM INTO UPSTATE NEW YORK SUN NIGHT. MID LEVEL CONFLUENT FLOW AND WARMING MID LEVEL TEMPS ACROSS SE MI ON SUNDAY IN THE WAKE OF THE UPPER LOW WILL SUPPRESS CONVECTIVE CLOUD DEPTHS DURING THE DAY. THE LOW LEVEL FLOW WILL ALSO BE NORTHWESTERLY...FORCING ANY RESIDUAL LAKE HURON ENHANCEMENT EAST OF THE THUMB. THESE FACTORS REMAIN SUPPORTIVE OF A DRY FORECAST. A LINGERING LOW LEVEL THERMAL TROUGH WILL HOWEVER REMAIN OVER SE MI THROUGH THE DAY...LEADING TO CONTINUED COOL TEMPS. MODEL SOUNDINGS ARE RATHER BULLISH WITH THE DEGREE OF DRY AIR ON SUNDAY AND SUPPORT A FAIR AMOUNT OF SUNSHINE. THERMAL TROUGHING OVER THE GREAT LAKES MAY HOWEVER SUSTAIN LOW LEVEL CYCLONIC FLOW A LITTLE LONGER INTO THE DAY THAN MODEL SOLUTIONS SUGGEST. THIS AND THE POTENTIAL FOR A SHALLOW LAYER OF MOISTURE TO REMAIN TRAPPED UNDER THE INVERSION SUGGESTS AT LEAST A POTENTIAL OF SOME DIURNAL STRATO CU ENHANCEMENT. ANY DAYTIME CLOUDS WILL DIMINISH LATE IN THE DAY SUNDAY OR DURING THE EVENING AS THE LOW LEVEL FLOW BECOMES DECIDEDLY ANTICYCLONIC. THE SURFACE HIGH WILL SLIDE SOUTH INTO THE OH/TN VALLEYS SUN/SUN NIGHT...WHICH WILL LEAD TO AN INCREASING W/SW GRADIENT OVER SRN MI. THIS WILL LIMIT THE DEGREE OF RADIATIONAL COOLING SUN NIGHT AND WARRANTS HOLDING FCST MINS CLOSE TO GUIDANCE /UPPER 40S TO NEAR 50/. MID LEVEL HEIGHTS WILL REBOUND ACROSS THE ERN US EARLY NEXT WEEK AS LONG WAVE TROUGH AMPLIFICATION OCCURS ACROSS THE PACIFIC NORTHWEST AND NRN ROCKIES. THIS WILL FORCE THE SFC HIGH TO DRIFT TO THE EASTERN SEABOARD BY TUES/WED...LEADING TO PERSISTENT SW FLOW ACROSS LOWER MI. THE RESULTANT LOW LEVEL LEVEL WARM AIR ADVECTION WILL SUPPORT A WARMING TREND MON INTO WED...WITH HIGH TEMPS EXPECTED TO BREAK THE 80 DEGREE MARK TUES/WED. A MID LEVEL SHORT WAVE IMPULSE IS FORECAST TO LIFT OUT OF THE LONG WAVE TROUGH AND CROSS THE NRN GREAT LAKES LATE IN THE FORECAST PERIOD. FORCING AND INCREASING MOISTURE ALONG THE ASSOCIATED SURFACE FRONT WILL SUPPORT THE NEXT CHANCE OF CONVECTION LATE NEXT WEEK. && .MARINE... COLD AIR NOW ADVANCING ACROSS THE GREAT LAKES UNDER NORTH TO NORTHEASTERLY WINDS WILL SUPPORT UNSTABLE CONDITIONS DURING THE WEEKEND. OBSERVATIONS ACROSS THE REGION SUPPORT HAZARDOUS SMALL CRAFT CONDITIONS...WHICH ARE EXPECTED TO PERSIST THROUGH THE FIRST HALF OF THE WEEKEND. IN ADDITION TO THE INCREASING WIND AND WAVES...THIS INSTABILITY WILL RESULT IN A CHANCE OF WATERSPOUTS ACROSS ALL OF THE LAKES. THE GRADIENT WILL WEAKEN SATURDAY NIGHT INTO SUNDAY...ALLOWING WIND AND WAVES TO DECREASE. THE RISK FOR WATERSPOUTS WILL DECREASE DURING THE COURSE OF THE DAY SUNDAY AS WARMER AIR ALOFT OVERSPREADS THE REGION. && .AVIATION...ISSUED 1157 PM EDT FRI SEP 11 2015 A BROKEN VFR CEILING MAY BE ABLE TO GENERATE A SPRINKLE OR BRIEF LIGHT RAIN SHOWER DURING THE REST OF THE NIGHT. THE MAIN CONCERN IS THE POTENTIAL FOR MVFR STRATOCU ORIGINATING FROM LAKE HURON TOWARD SUNRISE. OBSERVATIONS SHORTLY AFTER MIDNIGHT MATCH MODEL DEPICTIONS OF LITTLE TO NO CLOUDS OVER THE WATER BUT THEN SHOW EXPANDING COVERAGE TOWARD 12Z. COLDER AIR YET TO ARRIVE OVER THE WARM LAKE WATER WILL MAKE THIS POSSIBLE. THE RESULTING COVERAGE OF MVFR CEILING WILL BE AUGMENTED BY THE INCREASE IN DAYTIME HEATING THROUGH THE MORNING OVER SE MICHIGAN WHICH COULD ALSO SUPPORT INLAND SURVIVAL OF SCATTERED RAIN SHOWERS THROUGH EARLY AFTERNOON. PREFER TO SEE HOW THIS TURNS OUT BEFORE ADDING RAIN TO THE TERMINALS. CEILING IS THEN EXPECTED TO LIFT INTO LOW END VFR DURING THE MID AFTERNOON AND BECOME SCATTERED DURING SATURDAY EVENING WITH LESS FLOW OFF THE LAKES. FOR DTW... VFR CEILING WILL BE GREATER THAN 5000 FT UNTIL AFTER SUNRISE. MVFR CEILING IS THEN EXPECTED TO RETURN THROUGH EARLY AFTERNOON BEFORE RISING INTO LOW END VFR DURING THE AFTERNOON. SHOWER ACTIVITY WILL ORIGINATE FARTHER NORTH AND WOULD BE VFR IF ANY CAN REACH DTW. //DTW THRESHOLD PROBABILITIES... * MODERATE FOR CEILING AOB 5000 FT AFTER SUNRISE THROUGH EARLY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EDT SUNDAY FOR LHZ421-441>443. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ422. LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LEZ444. && $$ SHORT TERM...CB LONG TERM....SC MARINE.......SC AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 151921 CCA AFDDTX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 321 PM EDT THU OCT 15 2015 .SHORT TERM...THROUGH TONIGHT COMPACT MID LEVEL WAVE DIGGING EAST-SOUTHEAST WITHIN A BROADER NORTHWEST FLOW CARRYING 130 KNOTS AT 250 MB NOW AT THE DOORSTEP OF SE MICHIGAN. SOUTHERN SECTIONS OF SE MICHIGAN /ROUGHLY SOUTH OF I-96/ WILL REMAIN FAVORABLY POSITIONED FOR VERY LIGHT SHOWER PRODUCTION THROUGH THE LATTER HALF OF THE AFTERNOON AS A NARROW ZONE OF INCREASED MID LEVEL FRONTAL FORCING STREAKS ACROSS. EVAPORATIVE COOLING WITHIN A DEEP WELL MIXED SUB CLOUD LAYER WILL CONTINUE TO LIMIT DURATION/AMOUNTS DURING THIS TIME. ALSO A WINDOW THROUGH THE EVENING PERIOD FOR SCATTERED LIGHT SHOWERS TO EMERGE FROM THE TRI-CITIES INTO THE THUMB...AS A PERIOD OF INCREASING CVA CAPITALIZES ON THE EXISTING STEEP LAPSE RATE ENVIRONMENT. THE SIZABLE INCREASE IN BOUNDARY LAYER DEPTH EFFECTIVELY TAPPING INTO THE 30-40 KNOT FLOW RESIDING ABOVE 925 MB...TRANSLATING INTO GUSTY CONDITIONS AREAWIDE. LOCALIZED STRONGER GUSTS UP TO 45 MPH REQUIRING AUGMENTATION FROM PASSING CONVECTIVE SHOWERS. OTHERWISE PEAK GUSTS IN THE VICINITY 35 MPH THROUGH THE DURATION OF THE PEAK HEATING CYCLE BEFORE DIMINISHING QUICKLY. GENERAL CLEARING TREND AFTER DUSK TONIGHT AS SE MICHIGAN SETTLES WITHIN A BRIEF PERIOD OF SUBSIDENCE BEHIND THE EXITING WAVE. LEAD WEAK COLD FRONT SWINGS THROUGH DURING THIS TIME...850 MB TEMPERATURES BACK TO AROUND 0C BY FRIDAY MORNING. LOWS AGAIN IN THE UPPER 30S TO AROUND 40 DEGREES. && .LONG TERM... WATER VAPOR IMAGERY SHOWS LARGE UPPER LEVEL TROUGH DROPPING SOUTHEAST INTO THE GREAT LAKES REGION...DELIVERING OUR COLD BLAST AS WE HEAD INTO THE WEEKEND. 12Z RAOB OUT OF INTERNATIONAL FALLS REVEALED AN 850 MB TEMP OF 2 C...WITH THE PAS MANITOBA CHECKING IN AT -10 C. AS USUAL WITH ARCTIC AIRMASS COMING OVER THE GREAT LAKES REGION...DIFFICULT TO JUDGE WHETHER THE INHERENT DRY AIRMASS WINS OUT OVER THE LAKES INSTABILITY/MOISTURE CONTRIBUTIONS. THE KEY LOOKS TO BE EMBEDDED UPPER WAVES IN THE NORTHWEST FLOW PROVIDING JUST ENOUGH SUPPORT...AND THAT LOOKS TO BE THE CASE TOMORROW. THERE IS SUBSTANTIAL CLOUD DEPTHS (4-10 KFT) AND SUFFICIENT CAPES WITH THE STEEP LOW LEVEL LAPSE RATES GENERATED...AND CONFIDENCE IS HIGH THERE WILL BE SCATTERED-NUMEROUS LIGHT SHOWERS AROUND...AS SUBZERO 850 MB TEMPS FILTER IN THROUGH THE DAY...WITH 700 MB TEMPS FALLING INTO THE -13 TO 14 C RANGE. THE COLD ADVECTION AND SHOWER/CLOUD DEVELOPMENT SHOULD ASSURE TEMPS HOLDING IN THE 50S. LOWERING INVERSION HEIGHTS AND LOSS OF DAYTIME HEATING FRIDAY NIGHT EXPECTED TO LEAD TO LOSS OF CLOUDS AND SHOWERS. ALTHOUGH...LAKE SUPERIOR-MICHIGAN CONNECTION BAND(S) WILL HAVE SHOT TO EXPAND SOUTHEAST THROUGH THE NIGHT WITH THE DIMINISHING NEAR SURFACE TURBULENCE. PREFERENCE IS TO STRAY A BIT ABOVE COLD MET GUIDANCE...AS STILL COULD BE SOME TRANSIENT CLOUDS (925 MB NEAR SATURATION WITH RESPECT TO ICE) AROUND AND SURFACE WINDS STAYING UP A BIT...AND WILL HOVER MINS AROUND 30/LOWER 30S. STILL LOOKING AT 850 MB TEMPS DOWN AROUND -6 C ON SATURDAY...AND CERTAINLY POSSIBLE TO GET SOME GRAUPEL WITH ANY SHOWER DEVELOPMENT...IF NOT STRAIGHT SNOW SHOWERS IF OCCURRENCE IS CLOSE TO MORNINGS LOWS. ONCE AGAIN...THERE LOOKS TO BE SOME SUPPORT AT THE 700 MB LEVEL AS TEMPS FALL NEAR -18 C...TRACKING THROUGH THE NORTHERN THUMB REGION...AND WILL BE CARRYING HIGH SCATTERED COVERAGE IN THAT LOCATION...TAPERING OFF POPS TOWARD THE OHIO BORDER. NO ADJUSTMENT MADE TO MAXES ON SATURDAY...STUCK IN THE MID/UPPER 40S...WITH MINS SATURDAY NIGHT AGAIN BELOW FREEZING MOST LOCATIONS...ULTIMATELY DEPENDENT ON CLOUD COVER ONCE AGAIN...AS WINDS LOOK TO BACK A BIT MORE OUT OF THE WEST. A CHANCE OF RAIN REMAINS FOR THE EASTERN THUMB REGION ON SUNDAY AS A WEAK LOW PRESSURE SYSTEM SLIDES ACROSS ONTARIO. THE REST OF SOUTHEAST MICHIGAN WILL REMAIN DRY ON SUNDAY AS HIGH PRESSURE MOVES OVER THE REGION. DRY WEATHER WILL CONTINUE FOR THE ENTIRE CWA THROUGH MONDAY NIGHT AS THE HIGH SLIDES SOUTHEASTWARD. THE NEXT CHANCE OF RAIN ARRIVES POTENTIALLY ON TUESDAY AS A LOW PRESSURE SYSTEM TRACKING ACROSS NORTHERN ONTARIO DRAGS A COLD FRONT ACROSS SOUTHEAST MICHIGAN. SINCE THIS SYSTEM HAS YET TO BE FULLY SAMPLED...THE TIMING AND TRACK IS STILL UNCERTAIN BETWEEN MODELS. HAVE ONLY PUT IN A CHANCE OF RAIN FOR TUESDAY THROUGH NEXT THURSDAY DUE TO THIS UNCERTAINTY. HIGH TEMPERATURES WILL SLOWLY MODERATE FROM THE UPPER 40S TO LOW 50S ON SUNDAY INTO THE LOW 60S BY NEXT WEDNESDAY. LOW TEMPERATURES WILL RISE FROM THE LOW 30S SUNDAY NIGHT INTO THE UPPER 40S BY WEDNESDAY NIGHT. && .MARINE... AN EXTENDED PERIOD OF STRONG WINDS AND ROUGH SEAS AS COLDEST AIR OF THE SEASON ARRIVES. GOOD LAKE INSTABILITY WILL CREATE LAKE EFFECT SHOWERS THROUGH THE FIRST HALF OF THE WEEKEND. THE FIRST COLD FRONT HAS SLIPPED SOUTH OF THE MARINE WATERS THIS AFTERNOON...ALLOWING FOR WINDS TO SHIFT TO A MORE WESTERLY DIRECTION. SECOND COLD FRONT WILL SLIP THROUGH TONIGHT INTO TOMORROW...SHIFTING WINDS TO NORTHWEST DIRECTION...AND GUSTS TO 30 KNOTS ARE EXPECTED OVER THE OPEN WATERS OF LAKE HURON WITH THE DEEP MIXING. A GRADUAL DECREASE IN WINDS IS EXPECTED ON SATURDAY...BUT WINDS VEERING TOWARD NORTH WILL SUSTAIN LARGE WAVES OVER SOUTHERN LAKE HURON. COULD BE ONE MORE BACKDOOR COLD FRONT SLIPPING THROUGH LAKE HURON ON SUNDAY...BUT FORECAST WILL FEATURE WINDS UNDER 20 KNOTS. && .AVIATION...ISSUED 1255 PM EDT THU OCT 15 2015 SOUTHWEST GUST FREQUENCY AND MAGNITUDE WILL INCREASE THROUGH THE LATTER HALF OF THE AFTERNOON WITHIN A DEEP MIXED LAYER. POTENTIAL REMAINS FOR GUSTS TO PEAK WITHIN THE 30 KNOT RANGE DURING THIS TIME. A FEW HIGH BASED CONVECTIVE SHOWERS /5 TO 6K FT CIGS/ WILL BE POSSIBLE...WHICH WILL PROVIDE A LOW PROBABILITY FOR AN ISOLATED GUST IN EXCESS OF 35-40 KNOTS. WIND SPEEDS AND GUSTINESS WILL EASE THIS EVENING AS DAYTIME HEATING CEASES. WINDS VEER TO NORTHWESTERLY DURING THIS TIME IN THE WAKE OF A FRONTAL PASSAGE. FOR DTW...GREATEST WINDOW FOR SOME HIGH BASED SHOWERS AND AN ACCOMPANYING INCREASE IN GUSTINESS CENTERED 18Z-21Z. SOUTHWEST GUSTS /230-250 DIRECTION/ OUTSIDE OF ANY SHOWERS PEAKING IN THE 30 KNOT RANGE. //DTW THRESHOLD PROBABILITIES... * LOW FOR CIGS AOB 5KFT THROUGH THIS EVENING. * LOW FOR IN EXCEEDING 230-250 DEGREE CROSSWIND THRESHOLDS THROUGH 22Z. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR MIZ047>049-053>055-060>063-068>070-075-076-082-083. LAKE HURON...SMALL CRAFT ADVISORY UNTIL NOON EDT SATURDAY FOR LHZ421-441>443. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ422. LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LEZ444. && $$ SHORT TERM...MR LONG TERM....SF/RK MARINE.......SF AVIATION.....MR YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 160741 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 341 AM EDT FRI OCT 16 2015 .SHORT TERM...TODAY AND TONIGHT THE NEXT COLD FRONT IS ALREADY ON ITS WAY...CURRENTLY TRACKING SOUTH INTO THE UPPER PENINSULA PER 07Z IR SATELLITE. LOOKING ALOFT...THE MODEL ADVERTISED MID LEVEL PV FILAMENT IS ALSO DIVING SOUTHWARD LENDING SOME MID LEVEL SUPPORT FOR SHOWERS IN THE VICINITY OF THE SFC FRONT. LAKE EFFECT BANDS ARE SETTING UP QUICKLY BEHIND THE FRONT DUE TO THE COLD AIR BEING USHERED INTO THE REGION. 850MB TEMPS CURRENTLY NEAR 0C WILL QUICKLY FALL TO AROUND -6C ONCE THE FRONT PASSES. TIMING OF THE FROPA LOOKS TO BE AROUND 14Z FOR MBS AND 18Z FOR DTW. THOUGH DEWPOINTS BEHIND THE FRONT IN SOUTHERN ONTARIO ARE FALLING INTO THE UPPER TEENS...LAKE MODIFICATION TO THE AIRMASS SHOULD KEEP THEM AROUND 30 THIS AFTERNOON AND IN THE UPPER 20S TONIGHT. THIS AFTERNOON WE WILL SEE ANOTHER ROUND OF SHOWERS DEVELOP AS THE COLD AIR ALOFT AND MID LEVEL VORTICITY COMBINED WITH MID OCTOBER SUN STEEPENS THE LOW/MID LEVEL LAPSE RATES ENOUGH TO GENERATE SCATTERED SHOWERS. THERE WILL NOT BE THE JET SUPPORT WE SAW ON THURSDAY TO HELP OVER EXCITE THE CONVECTION AND MIXING DEPTHS LOOK TO BE CAPPED BY A DEVELOPING INVERSION AROUND 650MB SO NOT EXPECTING THUNDER OR DOWN DRAFT WINDS LIKE WE SAW THURSDAY EITHER. WINDS IN THE MIXED LAYER LOOK TO TOP OUT AROUND 30 KNOTS DURING PEAK MIXING. SO WILL BE A BIT GUSTY BUT LIKELY TOPPING OUT AROUND 20 KNOTS. CLOUD SHIELD AND RESULTANT SHOWERS WILL ALL QUICKLY FADE AFTER SUNSET...WITH THE POSSIBLE EXCEPTION OF THE NORTHERN THUMB AND INTO THE SAGINAW VALLEY. THE CLOSER PROXIMITY TO THE LAKE SUPERIOR/MI MOISTURE PLUME MAY KEEP CLOUDS OVER THAT AREA LONGER INTO THE NIGHT. WITH THE DRY AIR MOVING IN...AND THE BL TRYING TO DECOUPLING UNDER CLEARING SKIES...LOOKS GOOD FOR TEMPS TO FALL OFF OVERNIGHT. MINOR TWEAKS TO MIN TEMPS WHICH WILL FALL TO AROUND 30F OUTSIDE OF THE DETROIT HEAT ISLAND. A FREEZE WATCH IS IN EFFECT AND WILL CONTINUE WITH THIS FORECAST PACKAGE. WILL NEED TO ASSESS EXTEND OF LINGER CLOUDS AND THE EFFECT ON OVERNIGHT TEMPERATURE TRENDS TO DECIDE IF AN UPGRADE TO FREEZE WARNING OR FROST ADVISORY IS NECESSARY. && .LONG TERM...SATURDAY THROUGH THURSDAY THE HIGH AMPLITUDE LONG WAVE TROUGH AXIS OVER ERN CANADA WILL ENSURE NORTHWEST FLOW ACROSS THE GREAT LAKES THROUGH THE WEEKEND. THIS WILL SUSTAIN A RESERVOIR OF COLD AIR ACROSS SE MI...THE COLDEST THUS FAR THIS AUTUMN SEASON. WITH 850MB TEMPS HOVERING BETWEEN -5 AND -7C AND WITH AMPLE DIURNAL CLOUD ENHANCEMENT...DAYTIME HIGHS BOTH SAT AND SUN WILL REMAIN LARGELY IN THE 40S. NIGHTTIME MINS WILL BE DEPENDENT UPON THE DEGREE OF CLEARING /IF ANY/. GIVEN THE MAGNITUDE OF COLD AIR AND LOW SFC DEWPOINTS /LIKELY DOWN INTO THE 20S/...PARTIAL NIGHTTIME CLEARING WILL BE SUFFICIENT ENOUGH TO SUPPORT FCST MIN TEMPS SAT AND SUN NIGHT DOWN INTO THE 20S AND LOW 30S. THE DEPTH OF COLD AIR WILL SUPPORT GOOD CONVECTIVE CLOUD DEPTHS ACROSS THE GREAT LAKES AND THUS LAKE EFFECT PRECIPITATION. THE LOW LEVEL FLOW WILL REMAIN NORTHWEST ON SATURDAY. THIS MAY ALLOW SOME RESIDUAL LAKE EFFECT SHOWERS TO PUSH INTO THE SAGINAW VALLEY AND THUMB FROM NRN LOWER MI. DAYTIME HEATING WILL HOWEVER ADD A DIURNAL COMPONENT. MODEL SOUNDINGS FOR SAT AFTN SUGGEST DECENT CLOUD DEPTHS ACROSS THE NORTHERN HALF OF THE FORECAST AREA...CLOSER TO THE MID LEVEL COLD POOL. THIS SUPPORTS AT LEAST CHANCE TYPE POPS ON SAT. CHANCES WILL BE LOWER SOUTH OF M 59 WHERE CONVECTIVE DEPTHS ARE EXPECTED TO BE MUCH LOWER. STEEP SFC TO 700MB LAPSE RATES WILL SUPPORT SOME GRAUPEL/SMALL HAIL IN SOME OF THE HIGHER INTENSITY SHOWERS ON SAT. CAN NOT RULE OUT SOME SNOW MIXING IN CONSIDERING THE DEGREE OF DRY AIR IN THE SUB CLOUD LAYER AND RESULTING LOW WET BULB ZERO HEIGHTS. SFC PRESSURE RISES NORTH OF LAKE HURON ON SUNDAY IN THE WAKE OF A MID LEVEL SHORT WAVE IMPULSE ROTATING AROUND THE WESTERN SIDE OF THE LONG WAVE TROUGH IS EXPECTED TO PUSH THE LAKE ENHANCED SFC TROUGH SOUTH ACROSS LAKE HURON. THIS MAY TURN THE WINDS TOWARD THE NORTH ACROSS THE THUMB REGION...SUPPORTING A CHANCE FOR SOME LAKE ENHANCED RAIN SHOWERS IN THIS AREA ON SUNDAY. MODEL SOLUTIONS SHOW A RATHER ABRUPT AIRMASS CHANGE ACROSS THE REGION ON MONDAY AS THE LONG WAVE TROUGH PUSHES EAST OF NEW ENGLAND AND SUBSTANTIAL MID LEVEL HEIGHT RISES OVERSPREAD THE STATE. STRONG LOW LEVEL W-SW FLOW ASSOCIATED WITH A STRENGTHENING ERN US ANTICYCLONE IS EXPECTED TO SEND 850MB TEMPS UP TOWARD +12C BY MON EVENING. THE WIND FIELD WILL SUPPORT GOOD DAYTIME MIXING... SUGGESTING HIGHS MAY BREAK 60 ON MONDAY. A WEAKENING SFC FRONT IS FORECAST TO SINK INTO LOWER MI MON NIGHT INTO TUES. WITH SE MI REMAINING ON THE WARM SIDE OF THIS BOUNDARY...TEMPS WILL BE ABOVE SEASONAL AVERAGES THROUGH MID WEEK. && .MARINE... ROUGH SEAS WILL OCCUR TODAY INTO AT LEAST EARLY SATURDAY IN THE WAKE OF A COLD FRONT NOW ADVANCING ACROSS THE REGION. THIS WILL BE THE COLDEST AIR THUS FAR THIS SEASON. THE DEPTH OF COLD AIR WILL LEAD TO VERY UNSTABLE CONDITIONS ACROSS THE LAKES. GUSTY WINDS AND LAKE EFFECT RAIN SHOWERS WILL RESULT. LATEST MODEL GUIDANCE REMAINS SUPPORTIVE THAT PEAK WIND GUSTS WILL REMAIN AT OR JUST UNDER 30 KNOTS. THE GRADIENT WILL RELAX A LITTLE ON SATURDAY AS SFC TROUGHING ESTABLISHES ITSELF ACROSS THE GREAT LAKES. THERE WILL HOWEVER BE A CONTINUED RISK OF WATERSPOUTS CONSIDERING THE DEPTH OF COLD AIR. THIS SURFACE TROUGH WILL PUSH SOUTH ACROSS LAKE HURON ON SUNDAY...POSSIBLY CAUSING AN INCREASE IN WINDS AND WAVES OVER THE SOUTHERN HALF OF THE LAKE AS THE WINDS TURN MORE TOWARD THE NORTH. THE LOW LEVEL FLOW WILL BACK SOUTHWEST SUNDAY NIGHT AND QUICKLY INCREASE ON MONDAY. THIS WILL BRING MUCH WARMER AIR TO THE REGION WHICH WILL EVENTUALLY INCREASE THE STABILITY OVER THE LAKES. PRIOR TO THIS...RESIDUAL LOW LEVEL COLD AIR WILL BE SUPPORTIVE OF ROUGH SEAS REDEVELOPING ON MONDAY. GUSTS MAY REACH OR EXCEED 30 KNOTS. WINDS SHOULD THEN DECREASE MON NIGHT INTO TUESDAY AS WARMER AIR OVERSPREADS THE LAKES. && .AVIATION...ISSUED 1200 AM EDT FRI OCT 16 2015 NORTHWEST WIND WEAKENED CONSIDERABLY AFTER THE PASSAGE OF THE COLD FRONT BY LATE EVENING. MODEST WEST WIND WILL THEN CONTINUE TO BRING DRY AND COOLER AIR INTO THE REGION IN SUPPORT OF A CLEARING TREND THROUGH ABOUT MID MORNING. AFTER THAT...A REINFORCING COLD FRONT WILL MOVE IN FROM THE NORTHERN GREAT LAKES AND COMBINE WITH DAYTIME INSTABILITY TO INCREASE COVERAGE OF CLOUDS AND SHOWERS RESULTING IN LOW END VFR CEILING AND VISIBILITY. WIND GUSTS BOTH PRIOR TO AND POST COLD FRONT ARE EXPECTED TO BE MORE MANAGEABLE AROUND 20 KNOTS THROUGH THE AFTERNOON. CLOUDS...SHOWERS...AND WIND WILL THEN DIMINISH FRIDAY EVENING IN SIMILAR FASHION AS TONIGHT. FOR DTW... AFTER A GUSTY EVENING...THE WIND WILL SETTLE FROM THE WEST AT 10 KNOTS OR LESS UNDER CLEAR SKY THROUGH THE NIGHT. AN INCREASE IN VFR CEILING BELOW 5000 FT IS TIMED FOR LATE MORNING THROUGH THE AFTERNOON AS WIND GUSTS INCREASE BUT REMAIN A MANAGEABLE AROUND 20 KNOTS. //DTW THRESHOLD PROBABILITIES... * MODERATE CEILING AOB 5000 FT LATE MORNING THROUGH THE AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR MIZ047>049-053>055-060>063-068>070-075-076-082-083. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 9 AM EDT SATURDAY FOR LHZ421-441>443. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DRK LONG TERM....SC MARINE.......SC AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 221936 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 336 PM EDT SAT AUG 22 2015 .SHORT TERM...THROUGH TONIGHT MID LEVEL RIDGE AXIS IN ADVANCE OF THE NEXT LOW PRESSURE SYSTEM...ALONG WITH SFC HIGH PRESSURE OVER THE GREAT LAKES...WILL KEEP LIGHT SOUTHERLY FLOW AND MOSTLY CLEAR SKIES OVER THE REGION THROUGH THE OVERNIGHT. PWATS DOWN AROUND A HALF ARE ENOUGH TO SUPPORT A SCATTERED DIURNAL CU FIELD TODAY...BUT THIS SHOULD ERODE BY ABOUT SUNSET WITH THE LOSS OF BL MIXING. THERE IS AN OUTSIDE CHANCE THAT SOME MID CLOUDS WILL SKIRT ACROSS SOUTHERN MI LATER THIS EVENING ASSOCIATED WITH A WEAKENING SOUTHERN STREAM WAVE TRACKING ALONG THE OHIO RIVER. THE DRY AIR IN PLACE SHOULD DO AWAY WITH MOST OF THIS MOISTURE SO NOT EXPECTING ENOUGH COVERAGE OR DURATION TO AFFECT THE GOING FORECAST. MID LEVEL HEIGHTS WILL SLOWLY FALL OVERNIGHT AS SUNDAYS TROUGH APPROACHES...BUT THE GRADIENT REMAINS WEAK THROUGH THE PERIOD. THIS SHOULD ALLOW THE BL TO DECOUPLE AND MINS TO DROP BACK INTO THE UPPER 50S BEFORE FLOW TURNS SW SUNDAY MORNING INCREASING BL MOISTURE AND TEMPS. && .LONG TERM...SUNDAY THROUGH NEXT SATURDAY OVERALL THE 12Z MODEL SUITE APPEAR TO HAVE A REASONABLE HANDLE ON THE VIGOROUS WAVE NOW MOVING INTO THE DAKOTAS. THIS SYSTEM WILL ROTATE INTO NRN ONTARIO BY SUN AFTERNOON WHILE DEVELOPING INTO A CLOSED MID LEVEL CIRCULATION. MEANWHILE...A SHORT WAVE IMPULSE WITHIN ITS BASE IS FORECAST TO LIFT INTO THE NRN GREAT LAKES LATE SUN...CAUSING THE LONGER WAVELENGTH TROUGH TO TAKE ON A NEGATIVE TILT AS IT ADVANCES INTO THE REGION. THE BETTER MID LEVEL HEIGHT FALLS WILL REMAIN FOCUSED ACROSS THE NRN GREAT LAKES. HOWEVER... UPPER DIVERGENCE ALONG THE NOSE OF AN 80 KT UPPER JET... INCREASINGLY DIFFLUENT FLOW ALOFT AND LOW LEVEL CONVERGENCE AHEAD OF A STRONG COLD FRONT WILL FAVOR GOOD LARGE SCALE ASCENT FOR UPWARD MOTION ACROSS SE MI SUN AFTERNOON. DESPITE THE EXTENT OF THE MOISTURE NOW OVER THE MIDWEST...THE RAPID EASTWARD MOVEMENT OF THE UPPER WAVE AND SLOW DEPARTURE OF THE LOW LEVEL ANTICYCLONE ACROSS THE ERN GREAT LAKES WILL CAUSE THE DEEP LAYER MOIST AXIS TO NARROW AS IT PUSHES INTO LOWER MI ON SUNDAY. THE RESULT WILL BE A BRIEF WINDOW WHERE MOISTURE WILL BE ADEQUATE TO SUPPORT PRECIP...MOST LIKELY DURING THE LATE AFTERNOON OR EARLY EVENING. UNIMPRESSIVE MID LEVEL LAPSE RATES AND THE POTENTIAL FOR DAYTIME MIXING TO LOWER SFC DEWPOINTS WILL LIMIT THE DEGREE OF AFTERNOON DESTABILIZATION. ASSUMING LOW LEVEL MOISTURE POOLING IMMEDIATELY ALONG THE SFC COLD FRONT CAN RAISE DEWPOINTS TOWARD 60F AND AFTERNOON TEMPS CAN RISE INTO THE LOW 80S...SB CAPE MAY APPROACH 1K J/KG. 0-6KM BULK SHEAR WILL ALSO RISE TO 30-40 KNOTS ALONG THE LEAD EDGE OF A 50-60 KNOT MID LEVEL SPEED MAX MOVING INTO LOWER MI. THERE REMAINS AT LEAST A CHANCE THAT THE MID LEVEL WIND FIELD WILL INCREASE PRIOR TO THE DEPARTURE OF THE INSTABILITY AXIS. THE INCREASE IN DEEP LAYER SHEAR AND DEGREE OF LARGE SCALE ASCENT WOULD SUPPORT A CHANCE FOR STRONG TO SEVERE STORMS LATE SUN AFTERNOON/SUN EVENING IF JUST WEAK/MARGINAL INSTABILITY IS REALIZED. FOR THIS REASON...THE SPC DAY2 CONVECTIVE OUTLOOK HAS THE ENTIRE FORECAST AREA IN A MARGINAL RISK. THE PASSAGE OF THE COLD FRONT SUN EVENING WILL USHER IN A MORE AUTUMN-LIKE AIRMASS AS 850MB TEMPS DROP INTO THE SINGLE DIGITS. COOL TEMPS WILL ACTUALLY PERSIST WELL INTO NEXT WEEK AS THE UPPER LOW WILL BE SLOW TO DEPART THE NRN GREAT LAKES. MODEL SOUNDINGS SUGGEST ONLY A SHALLOW MOIST LAYER ON MONDAY. WHILE THIS WILL BE ENOUGH TO GENERATE A GOOD CU FIELD...ENOUGH SOLAR INSOLATION WILL STEEPEN THE LOW LEVEL LAPSE RATES AND SHOULD RAISE DAYTIME HIGHS INTO THE 70S. A LITTLE BETTER MOISTURE DEPTH IS FORECAST TO ROTATE INTO SRN MI ON TUESDAY...WITH SLIGHTLY COOLER AIR ALOFT SUPPORTING A LITTLE BETTER CONVECTIVE CLOUD DEPTH. THIS SUGGESTS MORE EXTENSIVE CLOUD COVER ON TUES WITH A CHANCE OF DIURNALLY ENHANCED SHOWERS. UNDER THESE CONDITIONS HIGHS ON TUES MAY REMAIN IN THE 60S OVER MUCH OF THE AREA. UPPER LOW LIFTS AWAY FROM THE GREAT LAKES LATE IN THE WEEK WITH LOCAL HEIGHT RISES LEADING TO A MODEST WARMING TREND. && .MARINE... SOUTHEASTERLY WINDS WILL SLOWLY INCREASE AND BACK TOWARD THE SOUTH TONIGHT INTO SUNDAY MORNING WITH THE APPROACH OF A COLD FRONT ACROSS THE UPPER MIDWEST. STRENGTHENING STABILITY ACROSS THE LAKES WILL KEEP WIND GUSTS IN CHECK. THE COLD FRONT IS FORECAST TO TRACK ACROSS LAKE HURON/WRN LAKE ERIE SUN EVENING. THERE IS A CHANCE OF STRONG/SEVERE STORMS AHEAD OF THIS FRONT. THE PASSAGE OF THE FRONT WILL BE MARKED BY A VEERING OF THE WINDS TO THE WEST-NORTHWEST. COLDER AIR WILL ALSO OVERSPREAD THE GREAT LAKES AND WILL SUPPORT INCREASINGLY UNSTABLE CONDITIONS OVER THE WATER. THIS WILL LEAD TO GUSTY WINDS WHICH MAY PERSIST THROUGH THE MID WEEK PERIOD. && .AVIATION...ISSUED 137 PM EDT SAT AUG 22 2015 FAIRLY QUIET TAF PERIOD AS HIGH PRESSURE HOLDS OVER THE REGION FOR ANOTHER DAY. LIGHT SOUTH/SOUTHEAST WINDS WILL KEEP DRY AIR IN PLACE WHICH WILL ONLY ALLOW A FEW DIURNAL CU TO DEVELOP THIS AFTERNOON. SOME CIRRUS DEBRIS MAY START WORKING IN BY MORNING AHEAD OF THE NEXT COLD FRONT WHICH IS TARGETING SOUTHEAST MICHIGAN SUNDAY AFTERNOON. MVFR CONDITIONS LOOK TO HOLD OFF UNTIL AFTER THE TAF PERIOD ENDS. FOR DTW...VFR CONDITIONS SHOULD HOLD THROUGHOUT THE TAF PERIOD BUT A COLD FRONT APPROACHING SUNDAY AFTERNOON MAY RESULT IN DETERIORATING CONDITIONS AS EARLY AS LATE SUNDAY AFTERNOON. //DTW THRESHOLD PROBABILITIES... * MEDIUM FOR CEILINGS AT OR BELOW 5000 FT SUNDAY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DRK LONG TERM....SC/DT MARINE.......SC AVIATION.....DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 231820 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 220 PM EDT SUN AUG 23 2015 .SHORT TERM...TONIGHT STRONG WESTERLY JET (80 KNOTS AT 500 MB) AND MID LEVEL DRY SLOT IMPINGING ON LOWER MICHIGAN THIS AFTERNOON...PUSHING THE SURFACE COLD FRONT THROUGH THE STATE BY EARLY EVENING. NEARLY SOLID LINE OF SHOWERS AND SCATTERED-NUMEROUS THUNDERSTORMS OVER WESTERN LOWER MICHIGAN...BUT NO SEVERE WIND GUSTS THUS FAR. INSTABILITY OVER SOUTHEAST MICHIGAN REMAINS PATHETIC TO NIL...PER 18Z DTX SOUNDING DUE TO SURFACE DEW PTS IN THE UPPER 50S TO AROUND 60 DEGREES AND A WARMER THAN EXPECTED -8 C TEMP AT 500 MB. NONE-THE-LESS...NARROW RIBBON OF MOISTURE IMMEDIATELY AHEAD OF THE COLD FRONT WILL ATTEMPT TO BOOST LOW LEVEL MOISTURE/SURFACE DEW PTS BRIEFLY INTO THE MID 60S...WHICH COULD STILL BE SUFFICIENT TO ALLOW FOR A FEW LOW TOPPED ORGANIZED CELLS PRODUCING DAMAGING WINDS DUE TO INCREASE IN BULK SHEAR (0-6 KM TO AROUND 40 KNOTS/0-1 KM OF 15 TO 20 KNOTS) ALONG THE FRONT. WEAK/ISOLATED TORNADO REMAINS A REMOTE POSSIBILITY AS WELL. HOWEVER...MID LEVEL LAPSE RATES WILL NOT BE MUCH HELP (WEAK)...AS RELATIVELY WARM 500 MB TEMPS HOLD STEADY OR ACTUALLY MAY RISE SLIGHTLY AS MAIN MID LEVEL COLD POOL TRACKS CLOSER TO THE STRAIGHTS. ONCE COLD FRONT CLEARS THE CWA EARLY THIS EVENING...EXPECTING SKIES TO BE MOSTLY CLEAR...AS WE ARE DOMINATED BY THE MATURE DRY SLOT. MODEST LOW LEVEL COLD ADVECTION...LOWERING DEW PTS INTO THE 50S...COUPLED WITH WINDS ATTEMPTING TO DECOUPLE SHOULD TRANSLATE TO MINS IN THE 50S TO AROUND 60 DEGREES. && .LONG TERM...MONDAY THROUGH NEXT SUNDAY THE SEASONALLY DEEP UPPER LOW WHICH LIFTED NORTH OF MINNESOTA TODAY WILL SLOWLY MEANDER ITS WAY EAST ACROSS LAKE SUPERIOR AND NRN ONTARIO MONDAY THROUGH WEDNESDAY. THIS SYSTEM WILL RESULT IN A VERY AUTUMN-LIKE AIRMASS ACROSS THE FORECAST AREA THROUGH AT LEAST MID WEEK. AS STATED IN THE PREVIOUS LONG TERM DISCUSSION...THE MORE PROBABLE TIME PERIOD FOR SHOWERS WITH THIS SYSTEM WILL BE DURING THE PEAK IN THE DIURNAL HEATING CYCLE /AFTERNOON AND EVENING/...MAINLY TUES AND WED WHEN MOISTURE DEPTH WILL BE A LITTLE BETTER. HIGHEST POPS WILL CONTINUE TO BE ACROSS THE NRN PORTIONS OF THE FORECAST AREA...CLOSER TO THE MID LEVEL COLD POOL. THERE IS HOWEVER THE CHANCE THAT SMALLER SCALE SHORT WAVE PERTURBATIONS CIRCULATING AROUND THE PARENT UPPER LOW WILL TRIGGER SOME LIGHT SHOWERS OUTSIDE OF THE AFTN/EVNG TIME PERIODS. THE 12Z MODEL SUITE ARE INDICATING THE PASSAGE OF A SECONDARY SFC COLD FRONT/TROUGH AXIS ACROSS SE MI MON AFTERNOON. MOISTURE QUALITY ALONG THIS BOUNDARY DOES NOT LOOK HIGH ENOUGH TO SUPPORT SHOWERS /BETTER CHANCES OF ANY -SHRA WILL BE WITHIN THE POST FRONTAL COLD AIR ADVECTION THAT ARRIVES LATE/. DESPITE 850MB TEMPS DOWN INTO THE SINGLE DIGITS...A DEEPENING AND WELL MIXED BOUNDARY LAYER WILL SUPPORT AFTERNOON HIGHS ON MON INTO THE 70S OVER MUCH OF THE AREA /EXCEPT FOR PERHAPS THE TRI CITIES/. MODEL SOUNDINGS SHOW 20-30 KNOTS IN THE MIXED LAYER MON AFTERNOON...WHICH WILL LEAD TO RATHER BREEZY CONDITIONS. SLIGHTLY COLDER LOW LEVEL AIR...DEEPER MOISTURE AND BETTER CONVECTIVE CLOUD DEPTHS WILL SUPPORT OVERALL MOSTLY CLOUDY CONDITIONS TUES INTO WED. EXPECTED CLOUD COVER WILL LIMIT DAYTIME BOUNDARY LAYER DEPTH WHICH WILL WARRANT FCST MAX TEMPS ONLY IN THE 60S OVER MOST OF THE AREA. NIGGHTIME MINS THROUGH MIDWEEK WILL LIKELY HOLD IN THE 50S AS THE GRADIENT FLOW AND EXPECTED CLOUD COVER SUPPRESS THE EXTENT OF NOCTURNAL COOLING. UPPER HEIGHT RISES FOR THE END OF THE WEEK AS THE UPPER LOW PULLS AWAY LOOK TO LEAD TO A MODEST WARMING TREND INTO NEXT WEEKEND. UPPER NORTHWESTERLY FLOW WILL PROMOTE SURFACE HIGH PRESSURE AND DRY CONDITIONS THURSDAY AND FRIDAY. && .MARINE... A COLD FRONT WILL TRACK ACROSS LAKE HURON AND WESTERN LAKE ERIE THIS EVENING. THIS SYSTEM WILL TRIGGER SCATTERED THUNDERSTORMS...SOME OF WHICH MAY BE STRONG. THE PASSAGE OF THE FRONT WILL BE MARKED BY A VEERING OF THE WINDS TO THE WEST. COLDER AIR WILL THEN OVERSPREAD THE REGION DURING THE NIGHT AND LEAD TO INCREASINGLY UNSTABLE CONDITIONS ACROSS THE LAKES THROUGH THE DAY ON MONDAY. GUSTY WEST- SOUTHWEST WINDS AHEAD OF A SECONDARY COLD FRONT ON MONDAY WILL LIKELY LEAD TO SMALL CRAFT ADVISORY CONDITIONS...ESPECIALLY ON SAGINAW BAY. WHILE WINDS AND WAVES WILL GRADUALLY DECREASE MON NIGHT INTO TUESDAY...ADDITIONAL LOW LEVEL COLD AIR ADVECTION WITH THE PRESENCE OF A DEEP UPPER LEVEL LOW ACROSS THE NORTHERN GREAT LAKES WILL LEAD TO FAVORABLE CONDITIONS FOR WATERSPOUTS. THIS RISK WILL PERSIST THROUGH AT LEAST MID WEEK. && .AVIATION...ISSUED 1227 PM EDT SUN AUG 23 2015 LINE OF SHOWERS AND SCATTERED STRONG TO POSSIBLY SEVERE THUNDERSTORMS WILL TRACK THROUGH SOUTHEAST MICHIGAN LATE THIS AFTERNOON/EARLY THIS EVENING...ENDING FROM WEST TO EAST. EXPECTING SKIES TO QUICKLY CLEAR BEHIND THE COLD FRONT DURING THE EVENING HOURS...WITH BRIEF POST FRONTAL GUSTS OF 20 KNOTS OR SLIGHTLY GREATER. DRY SLOT IS THEN EXPECTED TO PERSIST OVERNIGHT...WITH LIGHT SOUTHWEST FLOW AND MAINLY CLEAR SKIES. SOUTHWEST WINDS WILL INCREASE TOMORROW...AS DAYTIME HEATING ENSUES...WITH FREQUENT GUSTS AROUND 25 KNOTS EXPECTED. MEANWHILE...A LOW VFR DECK OF CLOUDS SHOULD DEVELOP AND SPREAD SOUTH THROUGH THE DAY WITH COLD ADVECTION. FOR DTW...TIMING OF THUNDERSTORMS LOOKS TO BE RIGHT AROUND 00Z...WITH QUICK CLEARING BEHIND COLD FRONT DURING THE EVENING. CLOUDS ARE THEN EXPECTED TO STRUGGLE FILL BACK IN HEADING INTO MONDAY...BUT SOUTHWEST WINDS WILL BECOME STRONG (25 KNOTS) DURING THE DAYTIME HOURS. //DTW THRESHOLD PROBABILITIES... * LOW FOR CEILINGS AT OR BELOW 5000 FT OUTSIDE OF THE WINDOW OF SHOWERS/THUNDERSTORMS 21Z-3Z. * MEDIUM FOR THUNDERSTORMS WITHIN THE IMMEDIATE AIRSPACE BETWEEN 22Z-01Z. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...SF LONG TERM....SC/DT MARINE.......SC AVIATION.....SF YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 241953 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 353 PM EDT MON AUG 24 2015 .SHORT TERM... AFTERNOON THROUGH TONIGHT A TOUCH OF FALL WEATHER WILL BECOME MORE FIRMLY ESTABLISHED DURING THE REST OF TODAY THROUGH TONIGHT. THE IMPRESSIVE CLOSED UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT OVER NORTHERN ONTARIO AND DIRECT COOLER AIR...CLOUDS...AND SCATTERED SHOWERS INTO SOUTHEAST MICHIGAN ON MODERATE WESTERLY WIND. SATELLITE IMAGERY AND MODEL ANALYSIS FIELDS INDICATE A SPOKE OF HEIGHT FALLS AND ASSOCIATED VORTICITY MAX WILL ROTATE FROM OVER WISCONSIN THROUGH LOWER MICHIGAN DURING THE LATE AFTERNOON AND EVENING. THE SURFACE PRESSURE REFLECTION WILL MARK A SECONDARY COLD FRONT/TROUGH THAT WILL CARRY A REINFORCING SURGE OF COOL AIR INTO THE REGION AND TAKE TEMPERATURES DOWN ANOTHER STEP AFTER THE FRONT THAT MOVED THROUGH YESTERDAY. GUIDANCE MIN TEMPERATURES IN THE LOWER TO MID 50S WILL BE ON TARGET CONSIDERING CLOUD COVER AND MODERATE WIND HOLDING UP THROUGH THE NIGHT. MODEL TEMPERATURE PROJECTIONS ALOFT ARE HIGHLIGHTED BY READINGS DROPPING TO ABOUT 6C ON AVERAGE AT 850 MB AND TO NEAR -15C AT 500 MB OVER THE SAGINAW VALLEY AND NORTHERN THUMB TONIGHT. THESE READINGS ARE NEAR RECORD LOWS IN THE DTX UPPER AIR DATABASE THAT ARE 5.6C AND -15.6C RESPECTIVELY FOR THE 00Z 8/25 UPPER AIR RUN. A DEEPER MOISTURE PLUME ASSOCIATED WITH THE COLD POOL WILL SLIDE OVER CENTRAL LOWER MICHIGAN DURING THE EVENING AND MAINTAIN SOME INSTABILITY EVEN AFTER SUNSET...PERHAPS WITH A SMALL BOOST FROM LAKE MICHIGAN. CHANCE POPS/SCATTERED COVERAGE LOOKS GOOD BASED ON MESOSCALE MODEL OUTPUT DOWN TO ABOUT THE I-69 CORRIDOR. PLAN TO MAINTAIN DRY CONDITIONS IN THE DETROIT METRO AREA TO THE OHIO BORDER FOR NOW AND MONITOR PROGRESS OF LAKE INFLUENCE THROUGH THE NIGHT. && .LONG TERM... LARGE AND SEASONABLY COLD UPPER LEVEL CIRCULATION ENCOMPASSING THE GREAT LAKES REGION/ONTARIO WILL BE SLOW TO BREAK DOWN AND TRACK EAST OVER THE NEXT COUPLE OF DAYS. 12Z INL SOUNDING REVEALED AN 850 MB TEMP OF 1 C. MODIFICATION OF THIS AIRMASS WILL OCCUR...BUT LOOKS LIKE 850 MB TEMPS WILL BE IN THE 5 TO 6 C RANGE TO START THE DAY ON TUESDAY. THIS COOL CYCLONIC FLOW COMING OFF LAKE MICHIGAN SHOULD BE SUFFICIENT TO CARRY A MOSTLY CLOUDY FORECAST DURING THE DAY...WITH SUFFICIENT LOW LEVEL LAPSE RATES/CAPE (100 J/KG) TO CARRY LIGHT ISOLATED-SCATTERED SHOWERS...AS CLOUD DEPTHS LOOK TO BE ABOUT 6 KFT FEET WITH EQL LEVELS REACHING 10 KFT. A SHORTWAVE IS ALSO DIVING SOUTHEAST FROM CENTRAL CANADA INTO THE CIRCULATION...ROUNDING ALONG THE SOUTHERN MICHIGAN BORDER AROUND 00Z WEDNESDAY. BLEND OF MAV/MET GUIDANCE SUGGESTS HIGHS IN THE UPPER 60S TO AROUND 70 DEGREES. HEIGHTS WILL BEGIN TO REBOUND ON WEDNESDAY...BUT STILL ENOUGH RESIDUAL COLD AIR DOWN LOW...0 C AT 700 MB/6 C AT 850 MB TO SUPPORT POSSIBLE LAKE MICHIGAN ENHANCED SPRINKLES/ISOLATED LIGHT RAIN SHOWERS. COMPARABLE TO SLIGHTLY WARMER MAXES EXPECTED ON WEDNESDAY COMPARED TO TUESDAY. ASSUMING LOW LEVEL ANTICYLONIC FLOW BUILDING IN WEDNESDAY NIGHT IS ABLE TO SUPPORT CLEARING SKIES (A BIG IF OVER THE THUMB REGION WITH NORTHERLY FLOW OFF LAKE HURON)...CHILLY MINS IN THE 45 TO 55 DEGREE RANGE APPEAR IN THE OFFING AS WINDS ALSO DROP OFF. THURSDAY THROUGH MONDAY...HIGH PRESSURE OVER THE AREA AT THE END OF THE WEEK WILL GIVE WAY TO A MID AND UPPER LEVEL TROUGH LATE FRIDAY NIGHT. THIS WILL RESULT IN WIDESPREAD RAINSHOWERS AND ISOLATED THUNDERSTORMS LATE FRIDAY NIGHT THROUGH SATURDAY MORNING. SCATTERED SHOWERS COULD LINGER THROUGH MONDAY MORNING. && .MARINE... SOUTHWEST WINDS WILL EASE JUST A BIT TONIGHT...WITH GUSTS OF 25 KNOTS OR SLIGHTLY HIGHER EXPECTED TO BE CONFINED TO THE OPEN WATERS OF LAKE HURON. ELEVATED WINDS GENERALLY IN THE 15 TO 25 KNOT RANGE WILL PERSIST HOWEVER...SHIFTING TO THE NORTHWEST...AS POOL OF COLD AIR REMAINS OVER THE CENTRAL GREAT LAKES THROUGH WEDNESDAY. THE COLDER AIR ABOVE THE WARM LAKE WATERS WILL ALSO CREATE FAVORABLE CONDITIONS FOR WATERSPOUTS THROUGH WEDNESDAY. EXPANSIVE HIGH PRESSURE IN PLACE ON THURSDAY WILL LEAD TO LIGHTER WINDS...LINGERING INTO FRIDAY. && .AVIATION...ISSUED 1253 PM EDT MON AUG 24 2015 A SECONDARY SURGE OF COOLER AIR WILL MOVE FROM WISCONSIN THROUGH LOWER MICHIGAN DURING THE REST OF THE AFTERNOON AND EVENING PROVIDING CONTINUED SUPPORT FOR GUSTY WEST WIND AND VFR CEILING. A FEW LIGHT/VFR RAIN SHOWERS ARE ALSO POSSIBLE...MAINLY IN THE FNT TO MBS REGION. PLAN TO MONITOR RADAR TRENDS ON SHOWER COVERAGE AS EXPECTATIONS REMAIN THAT COVERAGE WILL BE TOO LOW TO INCLUDE AT THE TERMINAL LOCATIONS. THE CLOUD PATTERN WILL HOLD THROUGH MUCH OF TONIGHT AT VFR LEVELS BUT AT THE LOW END OF THE RANGE. A HINT OF MVFR IS POSSIBLE LATE TONIGHT THROUGH MID TUESDAY MORNING BUT POTENTIAL WILL BE BETTER WEST OF THE TERMINAL CORRIDOR DEPENDING ON CONTRIBUTIONS FROM LAKE MICHIGAN. FOR DTW... CEILING OF SHALLOW CUMULUS ABOVE 5000 FT IS EXPECTED TO SETTLE BELOW 5000 FT BY EVENING AS A SECONDARY FRONT MOVES THROUGH THE REGION. THE FRONT WILL ALSO SUPPORT CONTINUED GUSTY WEST WIND AROUND 25 KNOTS THROUGH MID EVENING. EXPECT CEILING BELOW 5000 FT TO HOLD THROUGH TUESDAY MORNING. //DTW THRESHOLD PROBABILITIES... * LOW FOR CEILING 5000 FT OR LESS THROUGH MID AFTERNOON...MEDIUM LATE AFTERNOON/EVENING THROUGH TUESDAY MORNING. * LOW FOR EXCEEDING CROSS WIND THRESHOLD ON 25 KNOTS GUSTS AVERAGING FROM 250 DURING AFTERNOON AND 280 DURING EVENING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...BEACH HAZARDS STATEMENT UNTIL 11 PM EDT THIS EVENING FOR MIZ049. LAKE HURON...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LHZ421-422- 441>443. LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR LEZ444. && $$ SHORT TERM...BT LONG TERM....SF/DE MARINE.......SF AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 101945 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 245 PM EST SUN JAN 10 2016 .DISCUSSION... STRONG LOW PRESSURE SYSTEM WHICH BROUGHT 2 TO 3 INCHES OF SNOWFALL TO MOST OF SOUTHEAST MICHIGAN AND WIND GUSTS OF 40 TO 45 MPH TODAY IS TRACKING OFF INTO EASTERN CANADA EARLY THIS EVENING. ARCTIC AIRMASS PLUNGING ON THE BACKSIDE INTO THE CENTRAL CONUS/GREAT LAKES REGION...WITH 12Z RAOB OUT OF INTERNATIONAL FALLS INDICATING -27 C AT 850 MB. AS USUAL WITH ARCTIC AIRMASS COMING OVER LAKE MICHIGAN...DIFFICULT IN DETERMINING IF DRY ORIGIN OF THE AIRMASS/SHORTER WESTERLY FETCH OVER LAKE MICHIGAN WILL BE OVERRIDING FACTOR VS THE EXCELLENT LAKE INDUCED INSTABILITY. INVERSION HEIGHTS ARE LOW TONIGHT...4000 FEET...BUT STEEP LOW LEVEL LAPSE RATES RESIDE IN FAVORABLE DGZ ZONE. SATURATION INDICATING AT 850 MB TONIGHT WITH TEMPS OF -20 C....AND WILL CONTINUE TO ERR ON HIGHER SIDE OF POPS (VS MAV/MET GUIDANCE) AND FORECAST HIGH SCATTERED LIGHT SNOW SHOWERS THROUGH THE NIGHT WITH ACCUMULATIONS UNDER 1 INCH. FLOW BECOMING A BIT MORE SOUTHWEST TOMORROW WILL TEND TO LIMIT ADDITIONAL ACTIVITY TO NORTHERN AREAS. WINDS STAYING UP AND AIRMASS MODIFICATION OFF LAKE MICHIGAN EXPECTED TO HOLD MINS IN THE LOWER TEENS. MUCH HIGHER CONFIDENCE IN DEVELOPING SNOW MONDAY EVENING/NIGHT AS INTENSE UPPER WAVE FROM THE ARCTIC CIRCLE DROPS INTO THE WESTERN GREAT LAKES...WITH GOOD LARGE SCALE LIFT/PV ADVECTION...AS ACTUAL SURFACE LOW/REFLECTION TRACKS THROUGH THE HEART OF THE STATE. MODEL SOUNDINGS INDICATING SATURATION ALL THE WAY UP PAST 15 KFT...WITH GENEROUS QPF AMOUNTS EXCEEDING TENTH OF AN INCH AS WE HEAD INTO TUESDAY. LOW LEVEL LAPSE RATES DURING THE DAY ON TUESDAY LOOK TO BE VERY STEEP WITH CAPES WITHIN THE DGZ EXCEEDING 50 J/KG AND CLOUD DEPTHS STILL 10 KFT. WITH THE STRONG WESTERLY FLOW OFF LAKE MICHIGAN AND WINDS INCREASING BETWEEN 30 TO 40 KNOTS WITHIN THE BOUNDARY LAYER...LOOKS LIKE WE WILL BE SET UP FOR SNOW SQUALLS AND LOCALIZED WHITE OUT CONDITIONS DURING THE DAY ON TUESDAY. TEMPERATURES IN THE LOWER 20S WILL LIMIT THE MELTING OF SNOW AS SALT BEGINS TO LOOSE ITS EFFECTIVENESS AS TEMPS DROP INTO THE UPPER TEENS WITHIN THE SQUALLS. BETWEEN THE WIDESPREAD SNOW MONDAY NIGHT AND THE MORE LOCALIZED/INTENSE NATURE ON TUESDAY...WIDESPREAD SNOWFALL ACCUMULATIONS OF 2 TO 4 INCHES APPEARS LIKELY WITH THE FAVORABLE SNOW RATIOS...AS 925 MB SPECIFIC HUMIDITIES SNEAK UP TO AROUND 2 G/KG EARLY TUESDAY. LOCALIZED HIGHER AMOUNTS ARE CERTAINLY POSSIBLE WITH ANY PERSIST NARROW BAND WHICH SETS UP DURING TUESDAY. DISTURBANCES ROTATING AROUND THE TIME-MEAN UPPER LOW OVER HUDSON BAY/SOUTHEAST CANADA WILL BRING PERIODIC LIGHT SNOW CHANCES FROM THE MIDDLE TO THE END OF THE WEEK. AFTER A CHILLY WEDNESDAY WITH HIGHS EXPECTED TO REMAIN IN THE TEENS...HEIGHTS WILL GENERALLY RISE SLIGHTLY AS THE LOWER HEIGHT ANOMALIES GET REORIENTED TO THE NORTH AND EAST...WHICH WILL RESULT IN A GRADUAL WARMING TREND INTO THE END OF THE WEEK. && .MARINE... ONGOING GALE FORCE WINDS WILL PERSIST THROUGH THE EVENING BEFORE SLOWLY DIMINISHING OVERNIGHT AS THE DEEP LOW PRESSURE SYSTEM CONTINUES TO EXIT OFF TO THE NORTHEAST. THIS WILL NOT ONLY RESULT IN A DECREASE IN WINDS SPEEDS OVERNIGHT INTO MONDAY MORNING BUT WILL ALSO LESSON THE AMOUNT OF FREEZING SPRAY. A LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP OVER THE WESTERN GREAT LAKES ON MONDAY...THEN DEEPEN AS IT TRACKS ACROSS LOWER MI MONDAY AND TUESDAY. WINDS WILL BACK SOUTHWEST AHEAD OF THIS SYSTEM ON MONDAY...THEN VEER NORTHWEST IN ITS WAKE ON TUESDAY. THERE IS A CHANCE FOR GALE FORCE WINDS IN ITS WAKE TUESDAY NIGHT. && .AVIATION...ISSUED 1207 PM EST SUN JAN 10 2016 THE SURFACE LOW NOW OVER SE ONTARIO WILL CONTINUE TO DEEPEN AS IT LIFTS TOWARD SRN QUEBEC THIS AFTERNOON. GUSTS OVER 30 KNOTS HAVE BEEN QUITE COMMON THROUGH THE COURSE OF THE MORNING. ONGOING COLD AIR ADVECTION WILL LIFT MIXING HEIGHTS DURING THE AFTERNOON...SUSTAINING A GOOD DEAL OF GUSTINESS TO THE WINDS. AS THE SYSTEM DEPARTS THE REGION THIS EVENING...THERE WILL A WEAKENING IN THE GRADIENT WHICH WILL LEAD TO A GRADUAL DROP IN THE WINDS. THERE IS AN AXIS OF LOW LEVEL MOISTURE ACROSS LOWER MI WHICH SHOULD SUSTAIN MVFR CIGS INTO THE EVENING. LIFTING INVERSION BASES MAY THEN SUPPORT RISING CEILINGS DURING THE NIGHT. FOR DTW...THE SWITCH IN THE WIND DIRECTION TOWARD 300 TO 310 DEGREES SHOULD HOLD AS THE PREDOMINATE WIND DIRECTION THROUGH THE AFTERNOON. THIS WILL HOWEVER ALLOW SOME OF THE LAKE EFFECT SNOW SHOWERS AND FLURRIES TO CONTINUE TO PUSH INTO THE AREA FROM THE WEST SIDE OF THE STATE. EXPECT ANY HIGHER INTENSITY SNOW SHOWER WILL BE VERY BRIEF AND NOT AMOUNT TO MUCH IF ANY ADDITIONAL SNOWFALL. //DTW THRESHOLD PROBABILITIES... * HIGH FOR CEILINGS AOB 5000 FEET THROUGH THE TAF PERIOD. * MEDIUM IN WIND GUSTS OUT OF 300 TO 310 DEG EXCEEDING CROSS WIND THRESHOLDS THIS AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 4 AM EST MONDAY FOR LHZ462>464. GALE WARNING UNTIL 6 AM EST MONDAY FOR LHZ361>363-462>464. GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LHZ421-422-441>443. HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST MONDAY FOR LHZ361>363. LAKE ST CLAIR...GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LEZ444. && $$ DISCUSSION...SF/DT MARINE.......SC AVIATION.....SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 112017 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 317 PM EST MON JAN 11 2016 .DISCUSSION... STILL EXPECTING SNOWFALL TOTALS OF 2 TO 4 INCHES TONIGHT THROUGH TUESDAY ACROSS SOUTHEAST MICHIGAN. COLD AIRMASS IN PLACE OVER SOUTHEAST MICHIGAN...AS 12Z DTX SOUNDING CAME IN WITH AN 850 MB TEMP OF -21 C. AS OF 3 PM...EVEN WITH PARTIAL SUNSHINE THIS AFTERNOON...TEMPERATURES HAVE REMAINED UNDER 20 DEGREES. WARM ADVECTION TONIGHT WILL SUPPORT TEMPERATURES RISING INTO THE LOWER 20S HOWEVER. WEAK UPPER WAVE AND ASSOCIATED SURFACE LOW OVER SOUTHEAST IOWA EARLY THIS AFTERNOON...PHASING WITH AND BECOMING ABSORBED BY VERY STRONG UPPER WAVE/PV/HEIGHT FALLS DROPPING INTO THE UPPER MISSISSIPPI RIVER VALLEY...WITH THE EXCELLENT 6 HR 500 MB HEIGHT FALL CENTER PROGGED TO TRACK ACROSS EXTREME SOUTHERN LAKE MICHIGAN BY 12Z TUESDAY. WITH THE PHASING AND CONTRIBUTIONS FROM THE GREAT LAKES...RAPID DEEPENING OF THE LOW IS EXPECTED AS IT TRACKS THROUGH CENTRAL LOWER MICHIGAN TUESDAY MORNING. THE 12Z NAM IS ACTUALLY CLOSE TO 5 MB TOO WEAK WHEN COMPARED TO MAJORITY OF THE MODELS... RAP13/HRRR/GFS/REGIONAL GEM. HOWEVER...THE LATEST 12Z EURO IS IN LINE WITH THE NAM...INDICATING A LOW CLOSE TO 1000 MB AS IT TRACKS THROUGH THUMB REGION EARLY TUESDAY MORNING (12-14Z). THIS HAS SOME IMPLICATIONS WITH WIND FIELDS TOMORROW...EVEN SO...WITH AT LEAST 35 KNOTS IN THE BOUNDARY LAYER AND WITH HEAVIER CONVECTIVE SQUALLS AROUND...EXPECTING GUSTS AROUND 35 MPH. 6 HR RISE/PRESSURE COUPLET WORKING THROUGH THE CENTRAL GREAT LAKES IS PRETTY GOOD...BUT NOT A GREAT COLD ADVECTION PUSH (ABOUT 4 C DROP IN THE 925-850 AVERAGE TEMP WHICH GOES FROM -10 C TO CLOSE TO -14 C BETWEEN 12-18Z TUESDAY) AS MODIFICATION OF AIRMASS COMING OFF LAKE MICHIGAN COMES INTO PLAY. THE ADDITION OF THE STRONG WINDS DURING THE DAY ON TUESDAY BEHIND THE LOW CREATING BLOWING AND DRIFTING OF SNOW...ALONG WITH LOCALIZED SNOW SQUALLS COMING OFF LAKE MICHIGAN WAS DECIDING FACTOR TO GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT THROUGH 7 PM TOMORROW. EXCELLENT LARGE SCALE ASCENT AND ISENTROPIC ASCENT DOWN LOW WITH SPECIFIC HUMIDITY AT 925 MB LEVEL INCREASING TO AROUND 2.25 G/KG IS EXPECTED TO PRODUCE A SOLID 2 INCHES ACROSS MOST LOCATIONS DURING THE MORNING RUSH HOUR COMMUTE. WITH THE LOW IN A DEEPENING PROCESS...THE THUMB REGION WILL HAVE THE LONGEST AND GREATEST SUSTAINED ISENTROPIC ASCENT AND WILL PROBABLY PUSH TOWARD 3 INCHES TUESDAY MORNING BEFORE THE LOW LEVEL CIRCULATION EXITS COMPLETELY. STEEP LOW LEVEL LAPSE RATES AND WESTERLY/COLD NORTHWEST FLOW OFF LAKE MICHIGAN WILL THEN SEND SNOW BANDS/SQUALLS EAST DURING THE DAY. THERE COULD BE A SHORT LIVED LULL WITH GOOD POST WAVE SUBSIDENCE DURING LATE MORNING HOURS...BUT WITH CONVECTIVE CLOUD DEPTHS REACHING TOWARD 10000 FEET DURING THE AFTERNOON...LOCALIZED CONVECTIVE SQUALLS APPEAR LIKELY...WITH BRIEF WHITE OUT CONDITIONS POSSIBLE. MUCH LIKE LAST NIGHT/THIS MORNING...THERE WILL LIKELY BE NARROW SNOW SHOWER ACTIVITY PERSISTING WEDNESDAY NIGHT WITH 850 MB TEMPS CLOSE TO -20 C. THE LOW LEVEL FLOW LOOKS TO BE A BIT NORTH OF DUE WEST...SO MID SECTION OF CWA STANDS THE BEST CHANCE OF SEEING ACCUMULATING SNOW SHOWERS. BACKING SOUTHWEST FLOW ON WEDNESDAY SHOULD SHIFT BAND TO THE NORTH...BUT DRYING AND WARMING AT 850 MB WILL TEND TO DISSIPATE ACTIVITY BEFORE GOOD SURGE OF MID LEVEL WARM ADVECTION/FGEN TRANSLATES THROUGH WEDNESDAY NIGHT...POTENTIALLY SUPPORTING A PERIOD OF LIGHT SNOW. CONTINUED WAA WILL GIVE HIGHS A BOOST TO THE VICINITY OF THE FREEZING MARK THURSDAY WHILE LIGHT SHOW SHOWER ACTIVITY MAY PERSIST OVER THE NORTH HALF OF THE CWA AS THE WARM FRONT PROGRESSES NORTHWARD. ATTENTION THEN TURNS TO A CONSOLIDATING AREA OF VORTICITY AND ASSOCIATED TROUGH THAT IS PROGGED TO TAKE ON A NEGATIVE TILT AROUND THE MID-MISSISSIPPI VALLEY. PREDICTABILITY IS STILL RATHER POOR WITH THIS FEATURE WHICH RESULTS IN LOW CONFIDENCE IN THE TRACK OF THE ASSOCIATED SURFACE LOW AND EXPECTED SENSIBLE WEATHER. ENOUGH CONFIDENCE EXISTS TO INCLUDE LIKELY POPS FRIDAY NIGHT WITH CHANCE POPS FRIDAY AND SATURDAY. CONSENSUS DOES FAVOR WARMER AIR AHEAD OF THIS SYSTEM...SO P TYPE OF RAIN/SNOW IS IN THE FORECAST FRIDAY AND FRIDAY NIGHT. THIS SYSTEM DOES HAVE THE POTENTIAL TO IMPACT TRAVEL OVER THE WEEKEND. A RETURN BACK TO FRIGID TEMPERATURES IS LIKELY BEGINNING SUNDAY ON THE BACK SIDE OF THIS SYSTEM. && .MARINE... LOW PRESSURE DEEPENING WHILE MOVING THROUGH LOWER MICHIGAN TONIGHT WILL EXIT INTO ONTARIO TUESDAY MORNING. THIS SYSTEM WILL BRING A PATTERN OF SNOW OVER MUCH OF THE GREAT LAKES TONIGHT AND LEAVE COLD NORTHWEST FLOW...SNOW SQUALLS...AND FREEZING SPRAY POTENTIAL OVER THE REGION TUESDAY AND TUESDAY NIGHT. EXPECT GALES TO PEAK AROUND 40 KNOTS OVER THE OPEN WATERS DURING THIS TIME. THE PREVIOUS GALE WATCHES ARE UPGRADED TO WARNINGS FOR ALL MARINE AREAS EXCEPT FOR INNER SAGINAW BAY. THIS AREA IS SHOWN TO BE MOSTLY ICE COVERED IN SATELLITE DATA TODAY AND WILL BEHAVE MORE LIKE LAND AREAS FOR THIS EVENT. THE SAME COULD BE SAID FOR THE SMALLER MARINE ZONES OF LAKE ST CLAIR AND MICHIGAN WATERS OF LAKE ERIE BUT THE GUST POTENTIAL WILL BE GREATER IN THOSE AREAS FOR A FEW HOURS AROUND MID DAY TUESDAY. HIGH PRESSURE BUILDING INTO THE OHIO VALLEY WILL BRING QUICK IMPROVEMENT TO WIND AND WAVES WEDNESDAY FOLLOWED BY MODERATE SOUTHWEST FLOW THURSDAY INTO FRIDAY. && .AVIATION...ISSUED 1245 PM EST MON JAN 11 2016 BACKING LOW LEVEL FLOW WILL HELP BREAK UP THE REMAINING LAKE EFFECT SNOW SHOWERS AND WILL MAINTAIN VFR CEILING THROUGH THE AFTERNOON. CONDITIONS WILL THEN QUICKLY DETERIORATE THROUGH MVFR TO BORDERLINE IFR/LIFR ALL AREAS BY MID EVENING AS THE NEXT CLIPPER SYSTEM GAINS STRENGTH OVER THE GREAT LAKES. THE PEAK OF THE SNOWFALL EVENT WILL BE AHEAD OF THE SURFACE LOW TRACK DURING LATE EVENING THROUGH MID OVERNIGHT EXCEPT POSSIBLY A FEW HOURS LONGER AT MBS WHERE THE LOW IS EXPECTED TO TRACK NEARLY OVERHEAD. A GENERAL 2 TO 4 INCH ACCUMULATION IS FORECAST WITH GOOD CONFIDENCE BEFORE THE SYSTEM EXITS THE REGION DURING TUESDAY MORNING. COLD AIR RUSHING BACK IN BEHIND THE SYSTEM WILL PRODUCE WESTERLY WIND GUSTING NEAR 30 KNOTS BY MID TO LATE MORNING THROUGH TUESDAY AFTERNOON. BLOWING AND DRIFTING OF THE NEWLY FALLEN SNOW WILL COMBINE WITH INTENSE SNOW SHOWERS AT TIMES TO PRODUCE LOCALIZED IFR RESTRICTION. FOR DTW... LOW LEVEL WIND BACKING TOWARD THE SOUTHWEST HAS HELPED SCATTER OUT THE STRATOCU OVER THE DTW TERMINAL AREA WHICH WILL PERSIST THROUGH THE AFTERNOON. MEANWHILE...SNOW WILL CONTINUE TO DEVELOP OVER THE CHICAGO AREA DURING THE LATE AFTERNOON AND SPREAD INTO THE DTW AREA BY MID EVENING. CONDITIONS WILL QUICKLY DROP TO BORDERLINE IFR/LIFR CEILING AND VISIBILITY DURING THE PEAK OF EVENT WITH ACCUMULATION AROUND 3 INCHES BY MID TUESDAY MORNING. SURFACE TEMPERATURE WILL BE RISING THROUGH THE 20S OVERNIGHT WHICH IS EXPECTED TO SUPPORT A DRY/EFFICIENT SNOWFALL WITH THE SYSTEM. //DTW THRESHOLD PROBABILITIES... * LOW FOR CEILINGS AOB 5000 FEET DURING THE AFTERNOON...HIGH TONIGHT THROUGH TUESDAY MORNING. * HIGH FOR PRECIP TYPE AS SNOW THROUGHOUT THE FORECAST. * MODERATE FOR CROSS WIND CONSIDERATION LATE TUESDAY MORNING THROUGH TUESDAY AFTERNOON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 7 PM EST TUESDAY FOR MIZ047>049-053>055-060>063-068>070-075-076-082-083. LAKE HURON...GALE WARNING FROM NOON TUESDAY TO 4 AM EST WEDNESDAY FOR LHZ361>363- 462>464. GALE WARNING FROM NOON TUESDAY TO MIDNIGHT EST TUESDAY NIGHT FOR LHZ421-441>443. LAKE ST CLAIR...GALE WARNING FROM 7 AM TO 7 PM EST TUESDAY FOR LCZ460. MICHIGAN WATERS OF LAKE ERIE...GALE WARNING FROM 7 AM TO 7 PM EST TUESDAY FOR LEZ444. && $$ DISCUSSION...SF/DT MARINE.......BT AVIATION.....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 220100 AFDDTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 800 PM EST THU JAN 21 2016 .UPDATE... AN ENHANCED REGION OF LOW LEVEL CONVERGENCE STRETCHING FROM CENTRAL MI INTO THE NRN DETROIT SUBURBS HAVE LET TO AN INCREASE IN RADAR RETURNS IN THIS REGION OVER THE LAST HOUR. THE 00Z SOUNDING SHOWED CONVECTIVE CLOUD DEPTHS TO BE RATHER SHALLOW WITH A DEEP INVERSION NEAR 4000 FT. THE TEMP AT THE BASE OF THIS INVERSION IS HOWEVER -14C AND MOISTURE DEPTH IS RESPECTABLE. TEMPS WITHIN THE MOIST LAYER MAY ACTUALLY BE A TOUCH COLDER NORTH AND EAST OF THE DTX OBSERVED SOUNDING. SO THESE RETURNS ARE LIKELY GENERATING SOME DECENT DENDRITES. IN LIGHT OF THESE OBSERVATIONS...AN UPDATE TO CARRY SCATTERED SNOW SHOWERS TONIGHT IS NECESSARY. THERE IS CERTAINLY THE POTENTIAL FOR A FEW LOCALS TO PICK UP A DUSTING. && .AVIATION...ISSUED 602 PM EST THU JAN 21 2016 FORCING ALONG AN ELEVATED FRONTAL BOUNDARY AIDED BY LOW LEVEL MOISTURE SUPPORTED A CONSIDERABLE AMOUNT OF FLURRIES/LIGHT SNOW SHOWERS THIS AFTERNOON. RADAR TRENDS OVER THE LAST HOUR HAVE SHOWN A DIMINISHING TREND IN BOTH COVERAGE AND INTENSITY OF THE LIGHT SNOW AS THE ELEVATED FORCING DIMINISHES. ENHANCED LOW LEVEL CONVERGENCE WILL STILL HOWEVER SUPPORT AREAS OF MVFR CEILINGS AND FLURRIES THROUGH THE NIGHT. THE LOW LEVEL FLOW WILL TURN TO THE NORTHEAST OVERNIGHT...ALLOWING THE BETTER SFC CONVERGENCE TO SINK SOUTH. CURRENT CEILING HEIGHTS TO THE NORTHEAST OF THE FORECAST AREA ARE MUCH HIGHER DUE TO A LITTLE DRIER LOW LEVEL AIR AND HIGHER INVERSION HEIGHTS. THERE IS CONCERN THAT AS THE WINDS TURN NORTHEAST OVERNIGHT THAT CIGS WILL LIFT CONSIDERABLY. THE 18Z MODEL SOUNDINGS AND RECENT HI RES SOLUTIONS DO HOWEVER SUGGEST THAT MOISTURE FLUX OFF LAKE HURON WILL ALLOW SOME REDEVELOPMENT OF MVFR AND/OR LOW END VFR CIGS DURING THE OVERNIGHT WELL INTO FRIDAY. FOR DTW...THERE HAS BEEN SOME IMPROVEMENT IN CEILINGS ACROSS METRO DETROIT THIS PAST HOUR AS A LITTLE DRIER AIR HAS LIFTED INTO THE REGION FROM THE SOUTHWEST. THIS WILL LIKELY LEAD TO A CONSIDERABLE AMOUNT OF VARIABILITY IN CIGS DURING THE EVENING. AS LOW LEVEL CONVERGENCE TO THE NORTH BEGINS TO SINK SOUTH LATE THIS EVENING...THERE WILL BE A BETTER CHANCE FOR MORE WIDESPREAD MVFR CIGS AND FLURRIES. LATER IN THE NIGHT INTO FRI MORNING THERE IS A GOOD CHANGE THAT THE LOW LEVEL MOISTURE PLUME OFF LAKE HURON WILL REMAIN FOCUSED TO THE NORTHWEST OF METRO...WHICH WILL SUPPORT A PREVAILING MVFR CIG FOR THE TIME BEING. //DTW THRESHOLD PROBABILITIES... * MEDIUM IN CEILINGS AT OR BELOW 5000 FT THROUGH THE TAF PERIOD. && .PREV DISCUSSION...ISSUED 639 PM EST THU JAN 21 2016 UPDATE... WEAK UPPER LEVEL DEFORMATION ALONG A MID TROPOSPHERIC FRONT DRAPED ACROSS SRN LOWER MI IN COMBINATION WITH WEAK BOUNDARY LAYER CONVERGENCE AND A LAYER OF LOW CLOUDS EFFECTIVELY PRODUCED A LARGE REGION OF FLURRIES AND LIGHT SNOW THIS AFTERNOON. THE LARGER SCALE FORCING WILL WEAKEN DURING THE EVENING. THIS HAS ALREADY RESULTED IN A DECREASE IN BOTH INTENSITY AND AREAL COVERAGE OF THE SNOW SHOWERS. MODEL SOUNDINGS DO HOWEVER SUGGEST SUPPER SATURATION WITH RESPECT TO ICE IN THE LOW CLOUDS...WITHIN THE THERMAL REGION FAVORABLE FOR DENDRITIC GROWTH OF ICE CRYSTALS. THIS WILL LIKELY SUPPORT SCATTERED FLURRIES DURING THE NIGHT. AS THE FLOW BECOMES MORE NORTHERLY OVERNIGHT...A REGION OF ENHANCED BOUNDARY LAYER CONVERGENCE IS FORECAST BY LATEST HI RES SOLUTIONS TO SLIDE SOUTH ACROSS THE FORECAST AREA. THIS MAY SUSTAIN A LITTLE MORE WIDESPREAD COVERAGE OF FLURRIES /AND POSSIBLY EVEN LEAD TO A FEW SNOW SHOWERS OVERNIGHT/. AT THIS POINT THE EVENING UPDATE WILL INCLUDE SOME FLURRIES THROUGH THE NIGHT. PREV DISCUSSION...ISSUED 258 PM EST THU JAN 21 2016 DISCUSSION... TRANQUIL STRETCH OF WEATHER FOR THE AREA AS MAIN ACTION WILL TAKE PLACE ALONG THE EAST COAST. FOR THE REST OF THIS AFTERNOON AND EVENING A WEAK SURFACE TROUGH OVER THE AREA IS PRODUCING CLOUDS AND AREAS OF MAINLY FLURRIES. THIS TROUGH WILL DISSIPATE INTO THE NIGHT AND SO WILL FLURRIES. STORM SYSTEM ORGANIZING OVER THE WESTERN GOM WILL STRENGTHEN AS IT LIFTS UP THE EAST COAST THROUGH THE WEEKEND. A WEAK WAVE IN THE NORTHERN JET STREAM WILL DROP THROUGH THE GREAT LAKES FRIDAY AND GET ABSORBED BY THE SOUTHERN STREAM STORM SYSTEM. THIS WAVE WILL JUST BRING CLOUDS TO THE FORECAST AREA FRIDAY AS AVAILABLE MOISTURE WILL BE SCARCE AS MOISTURE TRANSPORT FROM THE SOUTH WILL BE BLOCKED BY SOUTHERN STORM. 500MB RIDGING WILL NOSE THROUGH THE GREAT LAKES FROM THE SW US THROUGH THE WEEKEND ALONG WITH WEEK SURFACE HIGH PRESSURE. THIS WILL BRING DRY SLIGHTLY WARMER THEN NORMAL TEMPS FOR THE WEEKEND ALONG WITH FAIR AMOUNT OF SUNSHINE. A WEAK SHORTWAVE IN THE NORTHERN JET WILL SKIM THE NORTHERN LAKES SUNDAY AND MAY BRING A BIT MORE CLOUDS TO THE SAGINAW VALLEY AND THUMB. THE NEXT MORE SIGNIFICANT SYSTEM WILL COME FROM A STRONG PACIFIC WAVE THAT WILL MOVE ASHORE THE WEST COAST SATURDAY AND HEAD EASTWARD SPINNING UP A SURFACE LOW OVER THE MID PLAINS. THIS SURFACE LOW WILL TRACK ACROSS NORTHERN LOWER MICHIGAN LATE MONDAY NIGHT INTO TUESDAY. SOME WARM AIR ADVECTION RAIN/SNOW SHOWERS WILL BE POSSIBLE LATE MONDAY INTO MONDAY NIGHT BEFORE CHANGING TO ALL SNOW TUESDAY AS ANOTHER SURGE OF ARCTIC AIR WRAPS IN BEHIND. SURFACE TROUGHINESS WILL EXTEND BACK FROM THE LOW AND LINGER THROUGH THE WEEK ENHANCING LAKE EFFECT SNOW SHOWER ACTIVITY. MARINE... HIGH PRESSURE REMAINS STALLED OVER THE GREAT LAKES LEADING TO RELATIVELY QUIET MARINE CONDITIONS THROUGH THROUGH THE WEEKEND. A STRONG LOW WILL TRACK NORTHWARD ALONG THE EAST COAST PROVIDING A BRIEF INCREASE IN NORTHEAST WINDS FRIDAY NIGHT RESULTING IN A LIMITED PERIOD OF HIGHER WAVE GROWTH ACROSS SOUTHERN LAKE HURON. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......SC AVIATION.....SC DISCUSSION...DRC MARINE.......DRK YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).  FXUS63 KDTX 071051 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 551 AM EST Mon Nov 7 2016 .AVIATION... Southeast flow off Lake Erie last evening brought added boundary layer moisture into metro Detroit, which led to the rapid development of fog. Per recent IR imagery, the thickest/more widespread fog is located along/southeast of the Irish Hills (extending from roughly Lapeer to Hillsdale). To the northwest of this line, the character of the fog has been more shallow, with greater visibility fluctuations. There is a south-southwest flow atop the nocturnal boundary layer. This is likely inhibiting the more widespread dense fog from pushing north of the hills. So any fog at MBS and FNT should erode fairly quickly after 13Z. PTK may be a little later, although recent IR imagery is indicating that the strengthening low level SW flow is already eroding the fog depth around PTK. The greater depth to the fog layer in metro Detroit suggests a late morning, possibly even early afternoon, erosion of the fog/low stratus. For DTW...The depth of fog across metro Detroit is such that it is going to take quite a while to mix out given the November sun angle. An increase in the SSW winds above the fog layer this morning does however add some degree of uncertainty in timing visibility increases above a quarter mile. Taking into consideration the expected increase in the low level flow, an improvement in the visibilities will be forecast to occur by 16Z. Recent model guidance does suggest additional southeast flow off Lake Erie this evening, which again may lead to fog development late in the evening. There is enough uncertainty with this scenario to support not going too aggressive in forecasting evening fog attm. Observational trends will however be monitored through the afternoon //DTW Threshold Probabilities... * High for ceiling/VV below 200 ft and/or visibility 1/2SM through mid morning. && .PREV DISCUSSION... Issued at 249 AM EST Mon Nov 7 2016 DISCUSSION... Southeast flow off Lake Erie yesterday evening introduced just enough near surface moisture to allow for dense fog to encompass much of southeast Michigan this morning. Dense fog advisory was expanded to the Thumb Region based off latest trends. Watching Flint Vicinity closely, but dense fog having tough time coming off the higher terrain of northern Oakland county with light southerly winds providing downsloping component. Winds trending light southwest across Tri-Cities region may also be enough to keep the widespread dense fog away there. High temperatures today really could end up anywhere between 55 to 70 degrees, ultimately dependent on when the fog mixes out, as pronounced upper level ridge and and very dry air aloft remains in place. Developing low level southwest flow during afternoon should help, and expecting dissipation around noon. Will thus forecast the middle road for highs, low to mid 60s, as 925 mb temps seen rising to 12 C, but mixing up to that level today is no guarantee. Strong upper wave/trough along the far southern Saskatchewan/Manitoba border to dive southeast through the Central Great Lakes on Tuesday. Model trends (especially GFS) a bit slower, indicating late day frontal passage. The northern stream wave attempts to merge with upper level energy and moisture over the central plains, and thus it appears the front will be a bit more active, with sufficient moisture and forcing indicated to support likely pops for south half of the CWA. Consolidating upper level PV/500 mb low quickly moves into the Central Appalachians Wednesday morning, with yet another amplified upper level ridge to build into the Great Lakes Region Wednesday afternoon/Wednesday Night. Strong warm advection pattern (850 mb temps rising into lower teens by Thursday) with surface winds attempting to decouple Wednesday night could set the stage for fog and/or low stratus development (see nam soundings), as westerly flow off Lake Michigan helps the cause. Strong westerly flow developing during Thursday ahead of a strong cold front dropping nearly due south from the Northern Great Lakes. Winds could be end up being stronger than the outgoing forecast if the low stratus does not develop Wednesday night and we get better mixing during the day on Thursday, tapping into at least 35 knots at 925 mb. Maxes could also potentially be warmer, reaching 60+. Heart of the Cold Air (850 mb temps of -10 C or colder) looks to be tracking through Eastern Great Lakes/New England on Friday, with southeast Michigan getting more of a glancing blow. None-the-less, still looks to be close call for potential Lake effect activity impacting the Eastern Thumb region, but at this time, it appears most of the activity will remain offshore with the low level winds being near 340 degrees. MARINE... The slow departure of sfc high pressure to the east of the Great Lakes today will place the region within increasing southerly flow. The persistence of very mild air atop Lake Huron will support continued strong over lake stability, thus limiting the strength of winds at the lake surface (gusts mainly under 20 knots). Lakes St Clair and Erie will see much lighter wind speeds today given the closer proximity to the sfc high. Winds will veer to the southwest tonight as a cold front approaches the region from the northwest. Strong stability in the prefrontal warm sector will keep strongest wind gusts below 25 knots. The cold front will traverse Lake Huron on Tuesday and Lake St Clair and Erie Tuesday evening, causing winds to veer to the northwest. Post frontal cold air advection will cause an uptick in the northwest winds Tuesday night. Recent guidance continues to suggest peak wind gusts topping out around 30 knots. Winds will then weaken Wednesday as high pressure expands across the region. Longer range models indicate a surge of arctic air overspreading the Great Lakes Thurs night into Friday, likely accompanied by northwest wind gusts around or above 30 knots on Lake Huron. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...Dense Fog Advisory until 10 AM EST this morning FOR MIZ049-054-055- 062-063-068>070-075-076-082-083. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....SC DISCUSSION...SF MARINE.......SC You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.  FXUS63 KDTX 292248 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 648 PM EDT Mon Apr 29 2019 .AVIATION... There will be a region of mid level subsidence building in behind the departing area of rain this evening. This will force remnant low level moisture to remain trapped beneath of deepening subsidence inversion, which should remain supportive of MVFR (perhaps some IFR) ceilings into the night with some areas of drizzle. There has been the development of a considerable amount of IFR and LIFR ceilings upstream across Wisconsin. Se Mi will however remain within persistent light east-northeast sfc winds through the night, which will attempt to advect a slightly drier airmass into low level across Se Mi. This suggests that ceilings heights will likely be highly variable through the night. Given the trends, a predominate low end MVFR cig will be forecast from PTK northward. IFR probabilities will be higher around metro Detroit where low level moisture content will be higher. For DTW...a weakening gradient will support continued weakening of the northeast winds this evening. Current ceiling trends suggest lower to IFR will be a little later into the evening (02Z or so). Again there is likely to be some degree of variable ceiling heights not just through the night but through the entire TAF period. .DTW THRESHOLD PROBABILITIES... * High in ceilings at or below 5000 ft tonight and Tuesday. && .PREV DISCUSSION... Issued at 345 PM EDT Mon Apr 29 2019 DISCUSSION... The upper level pattern over the next several days will bring an active weather stretch with several opportunities for rainfall with thunderstorms by mid-week. The first round of ongoing rainfall will continue through the remainder of the afternoon with the bulk of precipitation tapering off from east to west between 23- 01Z this evening. Large scale ascent with strong moisture transport riding over the boundary to our south is supporting these rain showers, which will continue into this evening as a surface low moves into OH. PWATs increasing to around 1 inch will support periods of moderate rainfall. Latest guidance keeps Showalter indices positive and instability remains south of Michigan, so will keep any mention of thunder out of the grids for the remainder of the day. There will be a brief lull in precipitation chances during the overnight time frame. Post frontal north to northeasterly flow will keep conditions cool with plenty of cloud cover sticking around. Lows tonight will drop into the mid 30s to low 40s. Troughing across the western US will set the stage for the mid-week activity as the southwesterly jet increases moisture transport into the Great Lakes region. A warm frontal boundary will set up south of MI tomorrow, which will allow for increased chances of precipitation before 2 pm across far lower MI as warm advection showers develop off of this boundary with increasing isentropic ascent. Upstream in the southern plains will be a southerly wave that gets ejected northward towards the Great Lakes bringing increasing rain chances beyond 2 pm into into Wednesday. PWAT values with this round of activity will increase towards the 1.50 inch range aided by that strengthening jet allowing for periods of moderate rainfall. Lighter rain showers through afternoon make way for a wave of heavier rainfall occuring roughly between 2 am and 8 am Wednesday morning. As this wave lifts northward, the warm sector will be drawn into central Michigan by Wednesday afternoon. This will then bring an opportunity for instability to increase and mid level lapse rates to improve bringing a chance of thunderstorms through the day. Greater thunderstorm potential currently resides across Lower MI from around I-94 and south. The warm advection lifting into lower MI will also bring increasing temperatures and leave a decent temperature gradient across the CWA. Looks like temperatures in the mid 50s to mid 60s along and north of I-69 and upper 60s to low 70s to the south. Thursday starts with the potential for a dry period before rain chances increase again by the afternoon and evening hours as another wave moves through the Great Lakes. This wave will bring light to moderate rain overnight into early Friday morning with weak midlevel instability perhaps resulting in a few rumbles of thunder. Temperatures Thursday will be dependent on how far north the warm front lifts with the approach of the wave and its timing, and will need better consensus among guidance before reaching a higher confidence forecast. For now, kept highs in the mid 50s to lower 60s in the north, to near 70 in the south. The wave will push a cold front through the region with dry northwest flow filling in on Friday. Surface high pressure will build in Friday and Saturday with midlevel subsidence associated with left entrance region of upper jet, resulting in a period of dry weather with temps near seasonal normal values. The next chance for rain comes late Sunday as an upper trough digs into the region. MARINE... Moderate easterly winds will exist through the evening period as a low pressure system tracks across the northern Ohio valley. Strongest winds noted from the southern lake Huron basin southward, where the wind speed will continue to support small craft advisory conditions. Winds briefly easing while backing to northerly tonight into Tuesday morning. A shift back to easterly late Tuesday, then increasing through Tuesday night as a stronger low pressure system lifts into the region. Winds remain forecast to hover around 30 knots late Tuesday night into Wednesday. Marine headlines will likely be needed on Wednesday. HYDROLOGY... Southeast Michigan will remain within a wet pattern through the late week period. Multiple episodes of rainfall are expected during this time, resulting in cumulative rainfall totals potentially exceeding 2 inches before this pattern eases Friday. Flooding concerns are not expected through Tuesday, as an initial round of rainfall this afternoon and evening results in amounts of less than half an inch. Widespread rainfall expected again Tuesday night through Wednesday, with another good chance Thursday. Potential exists for thunderstorms to contribute to localized higher rainfall totals during this time. This rainfall into already saturated ground conditions will leave the area increasingly susceptible to the possibility for flooding of poor drainage and urbanized areas, along with rises on rivers and streams. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...Lakeshore Flood Advisory until 10 PM EDT this evening for MIZ048- 076-083. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...Small Craft Advisory until 8 PM EDT this evening for LEZ444. && $$ AVIATION.....SC DISCUSSION...AA/TF MARINE.......MR HYDROLOGY....MR You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.