FXUS62 KGSP 210556 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 156 AM EDT SUN JUL 21 2013 .SYNOPSIS... HIGH PRESSURE OVER THE SOUTHEAST WILL WEAKEN DURING THE REMAINDER OF THE WEEKEND AS A COLD FRONT MOVES SOUTHWARD FROM THE GREAT LAKES. THE FRONT WILL STALL NORTH OF THE AREA ON SUNDAY AND THEN DISSIPATE OR RETURN NORTHWARD INTO MONDAY. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE EAST ON TUESDAY AND LINGER THROUGH LATE WEEK. A SECOND WEAK COLD FRONT WILL ARRIVE FROM THE NORTHWEST ON THURSDAY AND SETTLE JUST SOUTHEAST OF THE REGION THROUGH FRIDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 200 AM...CONDITIONS REMAIN RATHER CALM ACROSS THE REGION AS EARLIER CONVECTION HAS CEASED. LOW CLOUDS CONTINUE TO PREVAIL ACROSS MOST LOCATIONS WITH PATCHY FOG REMAINING LIKELY THROUGH MORNING. ADJUSTED TEMPERATURES AND DEWPOINTS TO REFLECT LATEST OBSERVATIONS AND LEFT THE REMAINDER OF FORECAST AS IS. PREVIOUS DISCUSSION... 1015 PM UPDATE...THUNDERSTORMS PERSIST AT THIS HOUR IN THE VICINITY OF A REMNANT GUST FRONT EXTENDING ACROSS THE LOWER SC PIEDMONT AND SOUTH SIDE OF THE CHARLOTTE METRO. LATEST SPC MESOANALYSIS SHOWS NEARLY 2000 J OF SBCAPE STILL UNINHIBITED JUST SOUTH OF THIS BOUNDARY...AS WELL AS A THERMAL GRADIENT IN THE SAME AREA THAT IS LIKELY PROVIDING ENOUGH FORCING TO GET PARCELS GOING. LIGHT SLY FLOW ON THE S SIDE OF THE BDY WILL CONTINUE TO REINFORCE THE GRADIENT AND IT MAY TAKE SOME TIME FOR THE REMNANT INSTABILITY TO BE CONSUMED. LATEST HRRR SUPPORTS THIS CONCEPT AS WELL AS THE SCHC POP WHICH HAS BEEN MAINTAINED OVERNIGHT FOR MOST OF THE CWFA...AS IT FEATURES A COUPLE OF ISOLATED CELLS HERE AND THERE...ESPECIALLY NEAR THE BLUE RIDGE. ON A FINAL NOTE...PATCHY FOG ALREADY DEVELOPING AT SOME SITES...PRIMARILY SITES WHICH SAW HEAVY RAIN THIS AFTN. FOLLOWING THAT THINKING THE MAIN AREA OF CONCERN WOULD BE THE FOOTHILLS AND UPPER PIEDMONT. AT THIS TIME THE REPORTING SITES ARE TOO SCATTERED TO NEED A DENSE FOG ADVY...AND NAM SOUNDINGS ARE NOT SUPPORTIVE OF WIDESPREAD DENSE FOG ANYWAY. HOWEVER...IT BEARS MONITORING AND WILL INFORM INCOMING SHIFT OF THIS CONCERN. AT 230 PM EDT SATURDAY...AN UPPER LEVEL TROUGH WILL SLOWLY AMPLIFY OVER THE EASTERN USA TONIGHT AND SUNDAY. A SHORTWAVE WILL MOVE INTO THE BASE OF THIS TROUGH OVER THE TN RIVER VALLEY LATE SUNDAY. DEEP GULF MOISTURE WILL BE TRANSPORTED NORTH INTO OUR AREA BY A GENTLE SW LOW LEVEL FLOW ON THE WEST SIDE OF A BERMUDA HIGH...WHILE A COLD FRONT DROPS SOUTH INTO VA. WITH LOW LEVEL FLOW NEARLY PARALLEL THE TO THE BLUE RIDGE...UPSLOPE FLOW WILL BE LIMITED...THOUGH STILL PRESENT. WITH THE LOWE LEVELS STABILIZING LATE THIS EVENING... CONVECTIVE COVER SHOULD DIMINISH. MODEL SOUNDINGS SHOW CAPE SURPASSING 1000 J/KG AGAIN ON SUNDAY...AND CONVECTIVE TRENDS ARE EXPECTED TO MIMIC TODAY...WITH THE GREATEST COVERAGE IN THE MOUNTAINS...WITH ACTIVITY SPREADING EAST INTO THE FOOTHILLS AND PIEDMONT WITH TIME. SHEAR WILL REMAIN WEAK HOWEVER...LIMITING STORM ORGANIZATION. MINIMUM TEMPERATURES WILL BE SEVERAL DEGREES ABOVE NORMAL TONIGHT IN A MOIST AIR MASS. MAXIMUM TEMPERATURES SUNDAY WILL BE SLIGHTLY BELOW NORMAL...WITH CLOUDS...MOISTURE A FALLING HEIGHTS ALOFT LIMITING WARMING. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... AT 230 PM SATURDAY... 500 MB HEIGHTS GRADUALLY LOWER OVER THE SOUTHEAST MONDAY AND TUESDAY BUT SURFACE PATTERN CHANGES WILL BE RATHER SUBTLE. DIURNAL CONVECTION WILL CONTINUE INTO THE FORECAST PERIOD BEGINNING 00Z MONDAY THEN GRADUALLY DIMINISH DURING THE NIGHT. MOIST AND MODERATELY UNSTABLE AIR MASS WILL CONTINUE OVER THE REGION AND GFS DEPICTS SHORT WAVE TROUGH APPROACHING CWA BY 12Z MONDAY... SO AT LEAST SLIGHT CHANCE POPS WILL CONTINUE WELL INTO THE NIGHT. DURING DAYTIME MONDAY... CWA REMAINS IN AIRMASS CONDUCIVE TO CONVECTIVE STORM DEVELOPMENT SO POPS WILL INCREASE WITH DAYTIME HEATING INTO CHANCE CATEGORY WITH LIKELY POPS OVER HIGHER TERRAIN. GFS HAS ANOTHER SHORT WAVE TROUGH DROPPING INTO LONG WAVE TROUGH POSITION EARLY TUESDAY... SO CHANCE POPS WILL CONTINUE THROUGH THE NIGHT AND INTO TUESDAY WHEN DIURNAL HEATING CYCLE ONCE AGAIN LEADS TO HIGHER PROBABILITIES DURING AFTERNOON. NO SIGNIFICANT TEMPERATURE CHANGES WILL OCCUR DURING MONDAY TUESDAY. HIGHS OUTSIDE THE MOUNTAINS WILL BE IN THE UPPER 80S AND LOWER 90S WHILE MOUNTAIN VALLEY TEMPERATURES WILL BE IN THE LOWER TO MIDDLE 80S. VERY WARM LOW TEMPERATURES IN THE 60S AND LOWER 70S ARE EXPECTED TO CONTINUE. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 230 PM SATURDAY... FLOW PATTERN ACROSS U.S. DURING THE PERIOD WILL CONSIST OF RIDGE IN THE WEST AND TROUGH OVER THE EASTERN STATES. BOUNDARY LAYER WILL REMAIN WARM AND MOIST SO COOL TEMPERATURES ALOFT ON WEDNESDAY WILL SUPPORT LAPSE RATES SUFFICIENTLY STEEP TO PROMOTE CONVECTION WITH APPROACH AND PASSAGE EARLY THURSDAY OF COLD FRONT. THEREAFTER DETAILS BECOME DIFFICULT TO RESOLVE AS FRONT DRIFTS SLOWLY SOUTHEAST AND APPEARS IN CURRENT GUIDANCE TO BECOME NEARLY STATIONARY JUST AFTER CROSSING CWA. THUS... AIR MASS CHANGE WILL NOT BE SUFFICIENTLY SIGNIFICANT TO ELIMINATE POPS BUT NUMBERS WILL BE IN THE LOWER END OF THE CHANCE SPECTRUM AND WILL DISPLAY A DIURNAL TREND. NO SIGNIFICANT CHANGES IN TEMPERATURE EXPECTED. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AT KCLT...CONTINUED WITH MOSTLY PERSISTENCE FORECAST FROM LAST NIGHT. EXPECTING MVFR FOG CONDITIONS TO DEVELOP IN THE NEXT HOUR OR SO ACROSS THE NC PIEDMONT WITH CIGS LESS THAT 1K FT. OTHERWISE...MVFR CONDITIONS WILL PREVAIL THROUGH MID MORNING THEN FINALLY GIVE WAY TO LOW END VFR CIGS BY AROUND NOON. AT THAT TIME...INTRODUCED MVFR PROB30 IN THE TAF FOR POSSIBLE AFTERNOON CONVECTION. EXPECTING AS MUCH...IF NOT MORE COVERAGE ACROSS THE REGION TODAY AS THE ATMOSPHERE CONTINUES TO MOISTEN. AFTER SUNSET EXPECTING CIGS TO LIFT ACROSS THE PIEDMONT TO SOLID VFR LEVELS AND REMAIN THAT WAY THROUGH THE REMAINDER OF THE TAF CYCLE. EXPECTING WINDS DURING THE PERIOD TO REMAIN LIGHT AND SOUTHWESTERLY. ELSEWHERE...RESTRICTIONS WILL CONTINUE...IF NOT WORSEN ACROSS THE REGION IN THE NEXT FEW HOURS AS VERY MOIST BOUNDARY LAYER SETTLES. LIKELY A REPEAT OF LAST NIGHT WITH REGARDS TO MVFR/IFR CIGS AT MOST SITES. IN ADDITION...ADDED TEMPO GROUPS FOR VISB RESTRICTIVE FOG AT ALL SITES WITH KAVL DROPPING DOWN TO AN IFR VISB. OTHERWISE...MUCH OF THE SAME AS KCLT ABOVE AS FAR AS MID MORNING LOW END VFR CIGS OVERSPREADING MOST OF THE AREA. BEYOND THAT...ADDED PROB30 GROUPS AT ALL SITES FOR MVFR TSRA RESTRICTIONS DURING THE LATE MORNING/AFTERNOON HOURS. EXPECTING CONVECTION TO INITIATE ACROSS THE HIGH TERRAIN FIRST...THEN SPREAD EASTWARD THROUGH THE PIEDMONT. CONDITIONS WILL IMPROVE THIS EVENING AS DAYTIME HEATING IS LOST AFTER SUNSET...WHERE SOLID VFR CIGS WILL RETURN. WINDS THROUGH THE PERIOD WILL BE LIGHT AND SOUTHWESTERLY. OUTLOOK...MOIST SOUTHWESTERLY FLOW CONTINUES INTO THE EARLY WEEK. THIS WILL HELP DRIVE SHOWERS AND THUNDERSTORMS...MAINLY IN THE AFTERNOON AND EVENING...AND LIKELY CAUSE RESTRICTIVE CIGS/VSBYS EARLY EACH MORNING. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT LOW 57% MED 79% HIGH 100% HIGH 100% KGSP MED 69% MED 77% HIGH 100% HIGH 100% KAVL MED 64% LOW 58% LOW 58% HIGH 100% KHKY MED 67% LOW 51% HIGH 85% MED 75% KGMU MED 71% LOW 59% HIGH 86% HIGH 100% KAND LOW 56% MED 77% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...CDG/JAT/WIMBERLEY SHORT TERM...LGL LONG TERM...LGL AVIATION...CDG  FXUS62 KGSP 280130 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 830 PM EST MON JAN 27 2014 .SYNOPSIS... A STRONG ARCTIC COLD FRONT WILL MOVE SOUTH OF OUR AREA TONIGHT INTO TUESDAY AS WAVES OF LOW PRESSURE TRACK NORTHEAST ALONG THE FRONT. WINTRY PRECIPITATION WILL FALL FROM THE GULF COAST TO EASTERN NORTH CAROLINA FROM TUESDAY INTO WEDNESDAY. EXPECT COLD HIGH PRESSURE TO BE OVER OUR REGION THROUGH THURSDAY...THEN TEMPERATURES WILL BECOME MILDER THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 830 PM...I WILL UPDATE THE FORECAST FOR TONIGHT THROUGH TUESDAY. THE LATEST SFC OBSERVATIONS INDICATES THAT THE COLD FRONT WAS SLIGHTLY EAST OF I-85. TEMPERATURES WILL FALL SHARPLY IN THE WAKE OF THE FRONT. IN FACT...HICKORY COOLED OVER 14 DEGREES OVER THE PAST THREE HOURS. THE UPDATE WILL CONTAIN SEVERAL ADJUSTMENTS IN HOURLY TEMPERATURES...DEWPOINTS...WINDS...AND SKY. TONIGHT...LOWS SHOULD RANGE FROM THE TEENS TO MID 20S EAST...OR 35 TO 40 DEGREES COLDER THAN TODAY/S HIGHS. STRONG CAA AND GUSTY WINDS WILL RESULT IN WIND CHILL VALUES FALLING IN THE SINGLE DIGITS BELOW ZERO. THE CURRENT WIND CHILL ADVISORY APPEARS WELL PLACED AND TIMED. SNOWFALL FORECAST...THE COLD FRONT IS EXPECTED TO BECOME NEARLY STATIONARY ACROSS NRN FL NE ALONG THE GA/CAROLINA COAST. BY 12Z TUES...THE AXIS OF A POSITIVELY TILTED H5 TROUGH WILL BE OVER THE CENTRAL PLAINS...PUSHING ACROSS THE MISSISSIPPI RIVER VALLEY BY 0Z WEDS. THE 18Z GFS IS CONSISTENT WITH PREVIOUS RUNS...INDICATING THAT A WIDE FIELD OF Q-VECTOR CONVERGENCE WILL DEVELOP ACROSS THE SOUTHERN APPALACHIAN REGION BETWEEN 18Z-0Z WED. HOWEVER...WEAKER MID LEVEL FORCING ARRIVES AROUND SUNRISE FROM THE WEST...PRIMARILY OVER THE NC MTNS. MODELS RESPOND TO THE EARLY MORNING FORCING WITH LIGHT QPF ACROSS THE TN BORDER OF THE NC MTNS. I WILL UPDATE THE FORECAST TO INDICATE AN EARLIER ONSET OF SNOW ACROSS THE WESTERN NC MTNS. BY MID DAY...AS THE MID LEVEL FORCING BEGINS TO INCREASE ACROSS THE REGION...AN AREA OF LOW PRESSURE WILL LIKELY DEVELOP OFF THE SC COAST ALONG THE STALLED FRONT. AS THE LOW DEEPENS...H85-H7 FRONTOGENESIS WILL INCREASE ACROSS CENTRAL NC AND THE UPSTATE OF SC...PEAKING BETWEEN 18Z AND 0Z. IN ADDITION...FORCING WILL DEEPEN WILL THE ARRIVAL OF THE MID LEVEL FORCING DURING THE PEAK OF THE LOWER LEVEL FRONTOGENESIS. THE RESULT SHOULD BE A BROAD AREA OF PRECIPITATION ACROSS THE SOUTHEAST...WITH THE BEST RATES BETWEEN 18Z-6Z. FORECAST SOUNDINGS INDICATE THAT THE CLOUD DEPTH WILL EXTEND FROM BELOW 1 KFT TO 35 KFT DURING THE PERIOD OF BEST FORCING. IN ADDITION...TEMPERATURES WILL SUPPORT PRECIP FALLING AS SNOW...WITH MOISTURE EXTENDING FAR BEYOND THE DENDRITIC CRYSTAL GROWTH ZONE. I WILL USE A BLEND OF THE WPC QPF WITH NAM THROUGH 0Z WED. THIS APPROACH WILL INCREASE SNOWFALL ACROSS THE NC MTNS AND ACROSS THE EASTERN PIEDMONT. SNOW RATIO GUIDANCE FAVORS VALUES AROUND 15 TO 1. THE AREA ACROSS GRAHAM TO SWAIN IS CLOSE TO ADVISORY SNOW. AS OF 145 PM EST...BROAD UPPER TROUGH WILL PERSIST EAST OF THE ROCKIES TONIGHT/TUE. COLD FRONT ASSOCIATED WITH THE NEXT PUSH OF ARCTIC AIR IS NOW ROUGHLY ORIENTED ALONG THE BLUE RIDGE. THIS FRONT WILL CONTINUE TO PUSH SOUTHEAST ACRS THE PIEDMONT THRU EVENING. FRONT IS FAIRLY SHALLOW AND STALLS JUST SOUTH OF THE CWFA TONIGHT...WITH SWLY FLOW BRINGING GULF MOISTURE ALONG IT. TEMPERATURES THIS AFTERNOON WILL BE ABLE TO REACH A TYPICAL DIURNAL MAX ACRS THE PIEDMONT...IN FACT A FEW DEGREES ABOVE NORMAL. TEMP TRENDS APPEAR MORE STEADY IN THE MTNS AS WINDS HAVE ALREADY SHIFTED TO NW. THE REALLY COLD/DRY AIR APPEARS TO HAVE ONLY REACHED THE CUMBERLAND PLATEAU...SO A SHARP DROP IS NOT EXPECTED TO BEGIN UNTIL LATE AFTN IN THE MTNS. MIDLEVEL CLOUD COVER WILL INCREASE ACRS THE AREA TONIGHT AS THE GULF MOISTURE ARRIVES...AND LIFT INCREASES AS RIGHT REAR QUAD OF UPPER JET SHIFTS OVERHEAD. FOLLOWING A FAVORED BLEND OF MOSTLY RAW TEMP GUIDANCE LOWS WILL MAINLY BE TEENS AND LOWER 20S NORTH...AND MID TO UPPER 20S SOUTH. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... AS OF 230 PM EST MONDAY...THERE WAS A TIGHTER CLUSTERING OF 3 TO 4 INCH SNOW AMOUNTS ON THE 0900 UTC SREF PLUME DIAGRAMS OVER THE SOUTHEAST PART OF THE FA...AS WELL AS AN INCREASE IN THE GEFS MEAN SNOWFALL AMOUNTS. THE 15 UTC PLUMES ARE NOT IN YET...BUT THE 15 UTC SREF 24 HOUR PLAN VIEW SNOW ACCUMS CONTINUE TO BE IN THE 3 TO 4 INCH RANGE IN THIS AREA. THEREFORE...SNOWFALL TOTALS HAVE BEEN RAISED TO 2 TO 4 INCHES ALONG AND SOUTH OF I-85. THE FATHER SOUTH ONE GOES...THE HIGHER THE TOTALS. AFTER COLLABORATION WITH NEIGHBORING OFFICES AND LOOKING AT THE 12 UTC GFS AND THE NOW WETTER 12 UTC ECMWF...TOTALS WILL BE HIGH ENOUGH OVER THE EXTREME SOUTHEASTERN PART OF THE FA TO ISSUE A WINTER STORM WARNING FOR HEAVY SNOW FROM UNION COUNTY ACROSS THE SRN TIER OF THE UPSTATE TO ELBERT CO GA. A WINTER WEATHER ADVISORY WILL BE ISSUED A COUPLE TIERS OF COUNTIES TO THE NORTH INCLUDING THE CHARLOTTE METRO AREA AND ALL OF THE NON MOUNTAIN ZONES OF THE UPSTATE. NORTHEAST GEORGIA IS A LITTLE TRICKIER...BUT THE PLAN FOR NOW IS TO ISSUE A WINTER WEATHER ADVISORY AS FAR NORTH AS STEPHENS COUNTY. I STILL DON/T SEE A STRONG CROSS-HAIR SIGNATURE ON ANY OF THE BUFKIT SOUNDINGS IN OUR FORECAST AREA...THOUGH THE HEAVIER SNOW WILL ACTUALLY BE SOUTHEAST OF ANY OF THE POINTS FOR WHICH BUFKIT DATA IS AVAILABLE. THERE IS A BROAD RATHER WEAK AREA OF H8-H7 FRONTOGENESIS OVER AND SOUTH OF I-85 ON THE NAM...AND THIS IS CONSISTENT WITH ACCUMULATIONS IN THE 2 TO 4 INCH RANGE OVER THE EXTREME SOUTHEAST. IT APPEARS THAT THE PCPN WILL FALL AS ALL SNOW OVER THE FORECAST AREA AS THE SOUNDINGS ARE SOLIDLY BELOW FREEZING AT ALL FORECAST SITES. SO THIS SHOULD BE A RARE ALL SNOW EVENT. THIS IS EVEN MORE REMARKABLE AS TEMPERATURES HAVE BALLOONED INTO THE 60S OVER PARTS OF THE FORECAST AREA THIS AFTERNOON. WITH LOWS FALLING INTO THE TEENS TO LOWER 20S TONIGHT...AND HIGHS NOT RISING ABOVE FREEZING TOMORROW...WE SHOULD SEE SNOW STICK TO MOST SURFACES. WHAT COULD BE WORSE IS THAT WE MAY SEE SOME INITIAL MELTING AND THEN REFREEZING ON ROADS. FINALLY...THERE WILL BE SHOT OF UPPER FORCING A LITTLE EARLIER IN THE DAY TUESDAY OVER THE NC MTNS. WITH HIGH SNOW TO LIQUID RATIOS A HALF INCH TO AN INCH OF SNOW IS POSSIBLE...ESPECIALLY OVER THE CENTRAL AND SOUTHWEST NC MTNS. FAIR AND COLD WEATHER WILL RETURN FOR WEDNESDAY AND WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 225 PM MONDAY...LOOKS LIKE AN UNSETTLED PERIOD THRU THE MEDIUM RANGE AS A SERIES OF SHORT WAVES ZIP THRU THE NEARLY ZONAL FLOW OVER THE AREA. AT THE SFC...MODIFYING ARCTIC HIGH PRESSURE WILL SLIDE EAST OF THE AREA THU AND REMAIN RIDGED WESTWARD INTO THE AREA FRI AS A COLD FRONT APPROACHES THE AREA. THU AND FRI WILL BE DRY WITH HIGHS AROUND 10 DEGREES BELOW NORMAL THU AND RISING TO NEAR NORMAL FRI. SLY LOW LEVEL FLOW DEVELOPS AHEAD OF THE COLD FRONT AS IT SLOWLY MOVES INTO THE TN VALLEY SAT. THIS BRINGS MOISTURE AND PRECIP INTO THE AREA LATE FRI NITE INTO SAT. TEMPS ARE COLD ENUF THAT PRECIP COULD BEGIN WITH A PERIOD OF FREEZING RAIN OVER THE NRN TIER...BUT IT SHOULD QUICKLY CHANGE OVER TO RAIN. THE COLD FRONT CROSSES THE AREA ON SUNDAY KEEPING A CHC OF RAIN OVER THE AREA. IN FACT...TEMPS WARM ENUF AHEAD OF THE FRONT THAT A FEW TSRA ARE POSSIBLE ACROSS THE PIEDMONT. PRECIP TAPERS OFF QUICKLY LATE SUN OR EARLY SUN NITE AS DRY HIGH PRESSURE BUILDS IN BEHIND THE FRONT. THIS DOES NOT LAST LONG AS THE HIGH QUICKLY MOVES EAST OF THE AREA BRINGING SLY LOW LEVEL FLOW BACK INTO THE AREA...ALONG WITH A DEVELOPING CHC OF RAIN BY LATE IN THE DAY MON. AS MENTIONED ABOVE...TEMPS WARM THRU THE PERIOD WITH ABOVE NORMAL READINGS SAT...AROUND 10 DEGREES ABOVE NORMAL SUN...THEN FALLING BACK TO NEAR NORMAL MON. LOWS FOLLOW A SIMILAR TREND. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... AT KCLT...LATEST SFC OBSERVATIONS INDICATE THAT THE COLD FRONT HAS PUSHED ACROSS THE TERMINAL. IN THE WAKE OF THE FRONT...NORTH WINDS SHOULD INCREASE INTO LOW TEENS THIS EVENING...WITH NE GUSTS DEVELOPING DURING THE LATE NIGHT HOURS. OTHERWISE...CONDITIONS TONIGHT WILL REMAIN VFR WITH ROUNDS OF HIGH CLOUDS. AFTER SUNRISE TUESDAY...NE WINDS WILL CONTINUE AS CLOUD BASES GRADUALLY LOWER. A BLEND OF PREFERRED MODEL GUIDANCE INDICATES THAT MVFR CEILINGS AND -SN WILL DEVELOP AROUND MIDDAY. AS MID LEVEL FORCING DEEPENS ACROSS THE PIEDMONT DURING THE LATE AFTERNOON...SNOWFALL AND ACCUMULATION RATES ARE EXPECTED TO INCREASE. I WILL INDICATE IFR VIS AND CIGS WITH -SN FROM 20Z THROUGH THE REST OF THE TAF PERIOD. BY 0Z...SNOW ACCUMS MAY REACH AROUND AN INCH...WITH AROUND 2 INCHES STORM TOTAL. ELSEWHERE...LATEST SFC OBSERVATIONS INDICATE THAT THE COLD FRONT HAS PASSED EAST OF KAVL AND KHKY...NEAR KAND...KGMU...AND KGSP. AS THE FRONT PUSHES EAST...ALL SITES WILL VEER WINDS FROM THE NORTH AND INCREASE SPEEDS BETWEEN 10-15 KTS. WINDS WILL VEER FROM THE NORTHEAST LATE TONIGHT...KAVL REMAINING FROM THE NORTH. AFTER SUNRISE TUESDAY...NE WINDS WILL CONTINUE AS CLOUD BASES GRADUALLY LOWER. A BLEND OF PREFERRED MODEL GUIDANCE INDICATES THAT MVFR CEILINGS AND -SN WILL DEVELOP BETWEEN LATE MORNING TO MIDDAY. AS MID LEVEL FORCING DEEPENS ACROSS THE REGION DURING THE LATE AFTERNOON...SNOWFALL AND ACCUMULATION RATES ARE EXPECTED TO INCREASE. I WILL INDICATE IFR VIS AND CIGS WITH -SN FROM 20Z THROUGH THE REST OF THE TAF PERIOD. OUTLOOK...SKIES WILL CLEAR WED UNDER COLD HIGH PRESSURE LASTING THROUGH THU. LIGHT PRECIPITATION AND SOME RESTRICTIONS MAY RETURN FRI-SAT AS LOW PRESSURE MOVES WEST OF THE AREA. CONFIDENCE TABLE... 01-07Z 07-13Z 13-19Z 19-01Z KCLT HIGH 100% HIGH 100% HIGH 92% MED 71% KGSP HIGH 100% HIGH 100% HIGH 87% HIGH 80% KAVL HIGH 100% HIGH 100% HIGH 85% HIGH 86% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 84% KGMU HIGH 100% HIGH 100% HIGH 86% HIGH 80% KAND HIGH 100% HIGH 100% HIGH 90% HIGH 91% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR GAZ018-026-028. WINTER STORM WARNING FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR GAZ029. NC...WIND CHILL ADVISORY UNTIL NOON EST TUESDAY FOR NCZ033-049-050. WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR NCZ057-070>072. WINTER STORM WARNING FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR NCZ082. SC...WINTER WEATHER ADVISORY FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR SCZ004>010. WINTER STORM WARNING FROM NOON TUESDAY TO 9 AM EST WEDNESDAY FOR SCZ011>014-019. && $$ SYNOPSIS...DEO NEAR TERM...NED/WIMBERLEY SHORT TERM...MCAVOY LONG TERM...RWH AVIATION...NED  FXUS62 KGSP 300011 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 811 PM EDT THU MAY 29 2014 .SYNOPSIS... A BACKDOOR COLD FRONT WILL SLOWLY CROSS THE FORECAST AREA FROM THE NORTHEAST THROUGH FRIDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTHEAST THIS WEEKEND...AND MOVE OFFSHORE EARLY NEXT WEEK. && .NEAR TERM /THROUGH FRIDAY/... 730 PM UPDATE...CURRENT EXPANSE OF VIGOROUS CONVECTION ALONG A LINE FROM BLACK MOUNTAIN ESEWD TO FORT MILL SEEMS TO REFLECT THE CONVERGENCE ALONG THE BACK DOOR FRONT. STILL HARD TO PICK OUT THE FRONTAL POSITION FROM OBS...BUT IN GENERAL SFC WINDS ARE NELY NORTH OF THIS LINE. RAP AND HRRR SEEM TO BE DOING A DECENT JOB HANDLING THE LLVL WIND FIELD AND THE HRRR RUNS HAVE BEEN RATHER GOOD WRT CONVECTIVE COVERAGE THIS AFTN. LATEST RUN CONTINUES TO LIGHT UP THE CONVERGENCE ZONE UNTIL AFTER MIDNIGHT. ENOUGH ELEVATED CAPE IS PRESENT TO THINK THIS IS STILL POSSIBLE. REVISED THE OVERNIGHT FCST TRENDS TO REFLECT A SOLUTION THAT IS MORE LIKE THE RAP/HRRR...HIGHLIGHTING THE AREA ALONG THE BOUNDARY FOR BEST POPS...AND SUPPORTING CONTINUED ELY FLOW TO ITS NORTH. FOR THE LATTER REASON THE BLUE RIDGE APPEARS TO BE AT A LITTLE HIGHER FLASH FLOOD THREAT WITH ANCHORING POSSIBLE...AS NOTED BY PREV SHIFTS. DENSE FOG IS A POSSIBILITY MAINLY IN THE MTN VALLEYS...WITH LOW STRATUS LOOKING MORE LIKELY OVER THE PIEDMONT. AS OF 300 PM...OVER THE NEXT 24 HOURS...THE MAIN CONCERN WILL BE THE FRONTAL ZONE DROPPING DOWN FROM THE NORTH. A SURFACE REFLECTION ALREADY SHOWS IN THE CAPE ANALYSIS NUDGING INTO THE NW PIEDMONT...WITH LOW CLOUDINESS AND STABLE AIR IN N CENTRAL NC. A SHORT WAVE DROPPING DOWN INTO THE UPPER TROF OFF THE EAST COAST WILL CONTINUE TO DRIVE THIS BOUNDARY FARTHER SOUTH AND EAST THIS EVENING. THE MODELS DO NOT REALLY SHOW MUCH IN THE WAY OF LOW LEVEL FORCING BUT THIS COULD BE MASKED BY THE DIURNAL CONVERGENCE TOWARD THE MTNS. IT STANDS TO REASON THAT THE BOUNDARY MAY PROVIDE THE FOCUS FOR CONVECTION WELL INTO THE NIGHTTIME HOURS. THERE IS SOME CONCERN FOR FLASH FLOOD POTENTIAL OVER THE NC BLUE RIDGE AND FOOTHILLS IF THE BOUNDARY MOVES FAR ENOUGH SOUTH TO DEVELOP A LOW LEVEL EASTERLY FLOW THAT COULD ANCHOR STORMS NEAR THE BLUE RIDGE...BUT NOT ENOUGH CONCERN TO ENTERTAIN A WATCH. EXPECT A DIURNAL REDUCTION IN STORM COVERAGE AFTER MIDNIGHT IN SPITE OF THE BOUNDARY...SO SOME OF THE LATEST SREF WAS BLENDED INTO THE POP. ON FRIDAY...SHOWERS AND STORMS SHOULD DEVELOP YET AGAIN ACROSS THE ENTIRE FCST AREA...BUT WE MIGHT BE COVERED WITH A LOW CLOUD CEILING BANKED UP AGAINST THE BLUE RIDGE THAT WILL CUT DOWN ON THE POTENTIAL FOR SEVERE STORMS. TEMPS SHOULD BE A BIT COOLER WITH THE ADDITIONAL CLOUD COVER AND EASTERLY FLOW DEVELOPING. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AT 215 PM EDT THURSDAY...ON FRIDAY NIGHT AN UPPER RIDGE OVER THE NORTHERN PLAINS WILL MOVE SOUTHEAST BETWEEN A CLOSED LOW OVER LA AND AND UPPER TROUGH OFF THE EAST COAST...REACHING THE SOUTHERN APPALACHIANS. THE RIDGE CENTER WILL MOVE OVER THE OH RIVER VALLEY ON SATURDAY...AND OVER GA ON SUNDAY. A BACK DOOR COLD FRONT WILL DRIFT VERY SLOWLY SOUTH ACROSS SC ON FRIDAY NIGHT...AND ACROSS THE SAVANNAH RIVER VALLEY ON SATURDAY. MODEL SOUNDINGS SHOW ELEVATED INSTABILITY VERY SLOWLY DECREASING ALONG THE BOUNDARY ON FRIDAY NIGHT...AND INCREASING AGAIN ON SATURDAY...MAINTAINING A THREAT OF CONVECTION AND HEAVY RAINFALL. ON SATURDAY NIGHT THE FRONT MOVES SOUTHWEST OF OUR AREA...BUT LINGERING LOW LEVEL MOISTURE AND AN EASTERLY UPSLOPE COMPONENT WILL SUPPORT A CHANCE PRECIPITATION ALONG THE SOUTHERN BLUE RIDGE ESCARPMENT. DRIER AIR WORKING INTO THE AREA FROM THE NW ON SUNDAY WILL REDUCE THE CHANCE OF PRECIPITATION...BUT THE MODEL SUGGEST THAT MOISTURE BANKED UP AGAINST THE SOUTHERN BLUE RIDGE WILL PERSIST...AND SMALL POPS WILL BE CARRIED THERE AGAIN. TEMPERATURES WILL RUN ABOVE NORMAL WITH RISING HEIGHTS ALOFT...UNTIL COOLER AIR BEHIND THE FRONT WORKS INTO THE AREA ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AT 215 PM EDT THURSDAY...ON MONDAY AN UPPER RIDGE WILL EXTEND FROM FL TO THE EASTERN GREAT LAKES...WHILE A CLOSED UPPER LOW WILL BE OVER THE WESTERN ATLANTIC AND AN UPPER TROUGH WILL BE OVER THE WEST COAST. THE UPPER RIDGE PROGRESS TO THE EAST COAST BY TUESDAY...WHILE A SHORTWAVE MOVES ACROSS THE GREAT LAKES AREA. THE PATTERN DEAMPLIFIES BY WEDNESDAY...LEADING TO A LARGELY ZONAL FLOW ACROSS THE NATION...AND WEAK FLAT RIDGING OVER THE SOUTHEAST...A PATTERN THAT PERSISTS INTO THURSDAY. SURFACE HIGH PRESSURE WILL BE CENTERED NEAR THE COASTAL VA AND NC ON MONDAY...AND ALTHOUGH GULF INFLOW ON THE WEST SIDE OF THIS RIDGE WILL BE FOCUSED OVER THE MS...TN AND OH VALLEYS...THE MODELS INDICATE MOISTURE OVER THE SOUTHERN APPALACHIANS...WITH UPSLOPE FLOW AND INCREASING INSTABILITY SUPPORTING DIURNALLY DRIVEN CONVECTION. AS THE SURFACE HIGH DRIFTS SE AND OFFSHORE FROM TUESDAY THROUGH THURSDAY...GULF INFLOW WEAKENS...BUT SPREADS EAST...COVERING NE GA AND THE WESTERN CAROLINAS. UPSLOPE FLOW INTO ELEVATED TERRAIN WILL BE RATHER WEAK...BUT ENOUGH TO SUPPORT THE BEST CHANCES OF CONVECTION REMAINING ALONG THE BLUE RIDGE...EVEN AS CONVECTIVE CHANCES INCREASE TO THE EAST. TEMPERATURES WILL RISE FROM NEAR NORMAL VALUES...TO ABOVE NORMAL... EVEN AS HEIGHTS FALL ALOFT...AS COOL NE FLOW VEERS TO THE SW... AND WARM ADVECTION ENSUES. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AT KCLT...CLUSTER OF TSRA WILL REMAIN NEARLY STATIONARY AT AND INVOF THE FIELD EARLY THIS EVENING...IN CONVERGENCE ZONE WHERE BACKDOOR COLD FRONT IS MEETING MOIST SOUTHERLY FLOW. HEAVY DOWNPOURS WILL LIKELY BRING IFR VSBY. FRONT IS MOVING SWWD VERY SLOWLY THRU THE PIEDMONT AND INSTABILITY WILL JUST HAVE TO BE DIMINISHED FOR THIS ACTIVITY TO END. MOST GUIDANCE MEMBERS INDICATE SOME KIND OF LOW STRATUS DEVELOPING BEHIND THE FRONT AS IT TRIES TO PUSH THRU THE AREA...HENCE MVFR CIG ARRIVES AFTER MIDNIGHT. ANY HEAVY RAIN COULD INCREASE FOG POTENTIAL THOUGH CONFIDENCE TOO LOW TO INCLUDE THIS. FRONT LINGERS IN THE AREA FRIDAY AGAIN WITH SUGGESTIONS OF INSTABILITY AND ASSOCIATED SHRA/TSRA CHANCES. THE WINDOW OF HIGHEST CHANCES IS A BIT WIDER DUE TO THE PRESENCE OF THE FRONT. INCLUDED AN MVFR PROB30 FOR THIS WINDOW. WINDS PREVAIL NE EXCEPT WHEN GUST FRONTS FROM TSRA PASS THRU. ELSEWHERE...OVERALL TRENDS SIMILAR TO KCLT. ELY WINDS WILL SPREAD ACRS THE NC PIEDMONT AND UP TO THE BLUE RIDGE AS FRONT MOVES SWD THRU THOSE REGIONS TONIGHT. MVFR CIGS...PERHAPS IFR ESP ALONG THE BLUE RIDGE...WILL EVENTUALLY DEVELOP. SHRA/TSRA ARE LIKELY TO CONTINUE ALONG THE FRONT WELL INTO THE EVENING. IFR FOG NOT OUT OF THE QUESTION WHERE RAIN FELL...BUT CONFIDENCE LOW GIVEN THE LOW CIGS LIKELY DEVELOPING FIRST. CHC-RANGE POPS WARRANT VC AND/OR PROB30 MENTION DURING THE DAY FRI. OUTLOOK...ALTHOUGH GRADUAL DRYING WILL DEVELOP FROM THE NE OVER THE WEEKEND INTO EARLY NEXT WEEK...CONTINUED BOUNDARY LAYER MOISTURE WILL PRODUCE ISOLATED TO SCATTERED DIURNAL CONVECTION EACH DAY...WITH MORNING RESTRICTIONS POSSIBLE. CONFIDENCE TABLE... 00-06Z 06-12Z 12-18Z 18-24Z KCLT HIGH 100% MED 78% HIGH 89% HIGH 100% KGSP HIGH 91% HIGH 95% HIGH 95% HIGH 100% KAVL HIGH 90% MED 72% HIGH 83% HIGH 88% KHKY HIGH 88% HIGH 81% MED 72% HIGH 100% KGMU HIGH 100% HIGH 83% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...JAT NEAR TERM...PM/WIMBERLEY SHORT TERM...JAT LONG TERM...JAT AVIATION...WIMBERLEY  FXUS62 KGSP 131125 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 725 AM EDT MON JUL 13 2015 .SYNOPSIS... THE EAST COAST WILL REMAIN UNDER THE INFLUENCE OF AN UPPER TROUGH...WITH MULTIPLE IMPULSES MOVING THROUGH THE AREA AND GOOD CHANCES OF SHOWERS AND THUNDERSTORM EACH DAY THROUGH THE FIRST HALF OF THE WEEK. A LOW PRESSURE SYSTEM AND STRONG FRONT WILL PASS THROUGH THE REGION TUESDAY...WITH STRONG TO SEVERE STORMS POSSIBLE. AFTER THE FRONT PASSES...AN UPPER HIGH WILL DRY OUT THE FORECAST AREA FOR THE SECOND HALF OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... 630 AM EDT UPDATE...ONGOING CONVECTIVE ACTIVITY PERSISTING AND BECOMING MORE WIDESPREAD ACROSS THE NRN MTNS...WILL UPDATE POPS A LITTLE. CONTEMPLATED AN FLS ACROSS NRN MADISON AS ONE HR RFC RATIOS APPROACHED 90 PERCENT. HAS SINCE RECEDED...HOWEVER INSTANTANEOUS RATES REMAIN FAIRLY HIGH WITH THESE CELLS...ARND 1.5 IN/HR. ONLY MINOR ADJS NEEDED TO T/TD GRIDS ACROSS THE UPSTATE AND NC PIEDMONT. ONGOING CONVEC WILL LINGER ACROSS THE FAR NRN ZONES THIS MORNING. NOT EXPECTING MUCH DEVELOPMENT WITH THESE CELLS AS ELCIN REMAINS HIGH AND THE UPPER VORT LOBE PROGRESSES EAST THROUGH NC/VA. UPPER HEIGHTS BEGIN TO FALL AND BECOME MORE CYCLONIC THROUGH THE DAY AS A VIGOROUS UPSTREAM MCS PUSHES INTO THE LOWER OH VALLEY. WEAK FLOW THROUGH THE MID LEVELS WILL ENCOMPASS THE CWFA THROUGH NOON BEFORE BECOMING DEFINED ZONAL IN THE LOW LEVELS. THE GFS AND NAM ARE BOTH SHOWING A VORT MINIMA CROSSING THE AREA AND CLOUD COVER SHOULD BE LOW ENUF FOR HIGH AMOUNTS OF INSOLATION AND SFC TD MIXING. THESE FACTORS WILL LIMIT THE CONVEC POTENTIAL ACROSS THE NON/MTNS AS LAYERED OMEGA REMAINS CLOSE TO NEUTRAL. THUS...POPS HAVE BEEN REDUCED TO LOW END CHANCES ACROSS THE NON/MTNS AND MAINTAINED A BIT ABOVE NORMAL OVER THE MTNS. THE VARIOUS CAM MODELS AGREE WELL WITH THIS SCENARIO WITH ONLY ONE OF THE ENS CAMS INDICATING A LITTLE WIDER ACTIVITY. SOME LATE AFTERNOON STRONG TO SEVERE STORMS ARE POSSIBLE OVER THE WEST AS DIFFLUENCE CONTINUES ATOP INCREASING 0-6 KM SHEAR WITHIN MODERATE INSTABILITY. MAX TEMPS WILL RESPOND WELL IN DOWNSLOPE FLOW WITH HIGHS REACHING THE M90S NON/MTNS...AND U80S MTN VALLEYS. THERE IS A GENERAL CONSENSUS BTW THE OP MODELS OF THE OH VALLEY MCS REACHING THE NC MTNS BTW 03Z-06Z. DEEP SHEAR LEVELS WILL CONTINUE TO INCREASE EASTWARD AND MODEST ELCAPE VALUES SHOULD BE MAINTAINED THROUGH MOST OF THE OVERNIGHT AND WITH THE ENERGIZED UPPER TROF APPROACHING...CONVECTIVE ACTIVITY WILL CONTINUE THROUGH DAYBREAK. LIKELY PRECIP CHANCES WILL BE HAD ACROSS THE MTNS WITH LOW TO MID CHANCES ELSEWHERE. LOCALIZED HIGH AMOUNTS OF QPF ARE POSSIBLE ACROSS THE UPSLOPE REGIONS WHERE ANCHORING STORMS MAY DEVELOP. WITH THE GOOD DYNAMICAL ENVIRON...A FEW OF THESE STORMS COULD ALSO BECOME QUITE STRONG TO SEVERE. THE NON/MTNS WILL EXPERIENCE MORE SCATTERED DEVELOPMENT WITH LOCALIZED QPF AMOUNTS ON THE ORDER OF A QUARTER INCH OF LESS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 200 AM MONDAY...A NORTHWESTERLY ALOFT PATTERN IS EXPECTED TO PREVAIL ACROSS OUR FORECAST AREA (FA) FOR THIS PART OF THE FORECAST CYCLE WHICH RUNS FROM TUE THROUGH WED NIGHT...WHILE A SERIES OF SHORT WAVES (S/W'S) RIPPLE SOUTHEASTWARD. A STRONG SHORTWAVE LOCATED NEAR THE GREAT LAKES AT 12Z TUES WILL DROP SE TOWARD AREA REGION WHILE A LEE TROUGH DEVELOPS NEAR OR OVER THE CAROLINA PIEDMONT DURING THE DAY TUES. THESE TWO FEATURES COMBINED WITH THE UNUSUALLY STRONG 30 TO 40 KT ZERO TO 6 KILOMETER COLUMN SHEAR WILL SET THE STAGE FOR MANY STRONG TO SEVERE THUNDERSTORMS TUES PM AND EVEN INTO THE OVERNIGHT. FALLING HEIGHTS WILL RESULT IN LOWER FREEZING LEVELS WHICH WILL MAKE LARGE HAIL A GREATER POSSIBILITY. WE ARE CURRENTLY UNDER THE ENHANCED RISK OF SEVERE FOR THE MTNS TUES PM AND SLIGHT RISK OUT OVER THE FOOTHILLS AND PIEDMONT. ALL MODES OF SEVERE ARE POSSIBLE...DAMAGING WIND...LARGE HAIL AND EVEN A TORNADO OR TWO. SUPERCELLS MAY DEVELOP FIRST AND PERHAPS TRANSITION INTO CLUSTERS OR LINEAR FEATURES. THE LEE TROUGH CONVECTION WILL BE SUPPORTED BY THE LATE PM HEATING AND THEN THE SHORTWAVE IS FORECAST TO ARRIVE AROUND 06Z WED. THEREFORE...SEVERAL HOURS OF SEVERE WX EXPECTED. THE NAM HAS A LINE OF CONVECTION FROM CENTRAL TN TO EASTERN NC AT 06Z WED MOVING SE. AFTER THE CONVECTIVE LINE CROSSES...THE MAIN SHORTWAVE TROUGH AXIS WILL SLOWLY CROSS OUR AREA DURING THE DAY WED. SOMEWHAT LOWER POPS NEEDED WED AS THE MAIN ENERGY MOVES OUT. WED IS THE TRANSITION DAY AS DRIER AIR IS POSED TO MOVE IN WED NIGHT FROM THE W AND NW WITH THE UPPER RIDGE EXERTING STRENGTH INTO OUR AREA WITH ITS CENTER BEING NEAR TX AND LA BORDER. WIND FLOW AT THE 850MB AND 700MB LEVEL DECREASES TO 20 TO 25 KTS AT THE END OF THE DAY WED. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 1235 AM MONDAY...THE MEDIUM RANGE BEGINS 12Z THURSDAY WITH THE UPPER TROUGH MOVING OFF THE EAST COAST AND UPPER RIDGE BUILDING IN FROM THE WEST. ON THURSDAY...THE CENTER OF THE 593DM 500MB RIDGE WILL BE OVER EAST TEXAS AND LA AREA...THEN RETROGRADE JUST A BIT OVER TEXAS THROUGH NEXT WEEKEND. FAIRLY DRY ATMOSPHERE THURSDAY AND FRIDAY...THEN THE 500MB FLOW BECOMES MORE NW OVER THE WEEKEND AND SHORTWAVES ROUNDING THE TOP OF THE RIDGE WILL AGAIN BE AFFECTING OUR AREA. DIURNAL HEATING WITH THE RESULTING INSTABILITY COMBINED WITH WHATEVER MOISTURE IS AVAILABLE ON THURSDAY AND FRIDAY WOULD CREATE PM CONVECTION. MODELS HAVE A FAIRLY GOOD SHORTWAVE CROSSING VA AND THE CAROLINAS IN THE NW FLOW LATE SATURDAY. SO BETTER CHANCES POP ARE WARRANTED FOR THAT DAY. A BIT BETTER 500MB TROFINESS ON SUNDAY WITH CONTINUED NW FLOW AT LEAST WEAK SHORTWAVES APPROACHING AND REACHING OUR AREA AT THE END OF THE CURRENT FORECAST PERIOD. MAX TEMPS AT LEAST A FEW DEGREES ABOVE NORMAL THROUGH THE MEDIUM RANGE. THERE IS SOME POTENTIAL OVER THE WEEKEND THAT ANY REMNANT MCS DEBRIS MAY LOWER MAX TEMPS WITH INCREASED CLOUD COVER. MAX TEMPS NEXT WEEKEND WERE BROUGHT DOWN A COUPLE DEGREES FROM PREVIOUS FORECAST DUE TO TREND FOR MORE OF A TROUGH AND UPPER RIDGE HAVING LESS OF AN INFLUENCE. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AT KCLT AND ELSEWHERE...POPS HAVE BEEN CUT BACK A BIT THIS AFTERNOON ACROSS THE NON/MTN TERMINALS...BUT ENUF OF A CHANCE IS NOTED IN THE CAMS FOR THE CONTINUATION OF THE PROB30 TSTMS AFT 18Z AT KCLT AS ULVL FLOW BECOMES MORE DIFFLUENT. MORNING VSBYS SHOULD REMAIN VFR...EXCEPT PERHAPS ACROSS THE LOCALIZED MTNS VALLEYS AND MAYBE ARND KHKY WHERE PRECIP HAS FALLEN OVER THE PAST FEW HRS. KAVL COULD SEE SOME LOWERING CIGS TO MVFR BUT TDD/S REMAIN TOO HIGH FOR A SIGFNT FG THREAT THROUGH DAYBREAK. ALL SITES REMAIN VFR THROUGH THE DAY OUTSIDE OF CONVEC. KAVL AND HKY COULD BEGIN TO SEE LOWERING CIGS AFT 03Z WITH MCS ACTIVITY REACHING THE MTNS. OUTLOOK...THE WEATHER PATTERN WILL BE MORE FAVORABLE FOR MAINLY AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS THRU MIDWEEK. HOWEVER...THERE COULD BE SOME ORGANIZED THUNDERSTORMS THAT MOVE ACROSS THE REGION LATE TUESDAY NIGHT. LOW CLOUDS AND FOG COULD ALSO DEVELOP IN THE MORNING AT PLACES THAT HAVE SHOWER ACTIVITY THE DAY BEFORE...AND IN MTN AND RIVER VALLEYS. CONFIDENCE TABLE... 11-17Z 17-23Z 23-05Z 05-06Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...SBK SHORT TERM...DEO LONG TERM...DEO AVIATION...SBK  FXUS62 KGSP 110553 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 153 AM EDT TUE AUG 11 2015 .SYNOPSIS... RETURN FLOW OFF THE GULF OF MEXICO WILL BRING IN MOISTURE AHEAD OF AN APPROACHING COLD FRONT. EXPECT SHOWERS AND THUNDERSTORMS AHEAD OF THE FRONT UNTIL THIS FRONT PASSES LATE TUESDAY. COOLER AND DRIER HIGH PRESSURE WILL BE IN CONTROL OF OUR WEATHER FROM WEDNESDAY INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TODAY/... AS OF 145 AM EDT TUESDAY...LIGHT/MODERATE SHOWERS CONTINUE TO MOVE ACROSS THE UPPER SAVANNAH RIVER VALLEY THIS MORNING. THE ATMOSPHERE REMAINS RELATIVELY STABLE THUS HAVE NOT SEEN ANY LIGHTNING IN THE LAST 3-4 HOURS WITH ANY OF THESE CELLS. THUS...LOWERED THUNDER CHANCES A BIT...HOWEVER KEPT POPS AT LIKELY LEVELS. OTHERWISE...TWEAKED TEMPS/DEWS AND SKY TO ACCOUNT FOR MOST RECENT OBS/SAT. PREVIOUS DISCUSSION... AS OF 430 PM EDT MONDAY...HI-RES GUIDANCE NOT HANDLING THE CONVECTION ACROSS NORTH GEORGIA VERY WELL AT ALL...MOST HAVE A BLOB OF CONVECTION BUT NOT PUSHING THROUGH NORTH GEORGIA FOR SEVERAL HOURS STILL. HAVE MADE SEVERAL NEAR-TERM ADJUSTMENTS TO POPS BASED ON OBSERVATIONAL TRENDS...INCREASING POPS TO LIKELY ACROSS MOST OF THE AREA TO ACCOUNT FOR SCATTERED CONVECTION AHEAD OF THE LINE MOVING THROUGH NORTH GEORGIA...AND CATEGORICAL FOR EXTREME WESTERN ZONES. SAW SEVERAL REPORTS OF WIND DAMAGE ACROSS NORTHWEST GEORGIA BUT LOOKS LIKE THE LINE MAY BE FALLING APART...DESPITE PRESENCE OF NICE BOW ECHO ON REFLECTIVITY...AS IT PUSHES INTO THE MOUNTAINS. HOPEFULLY THE DOWNWARD TREND WILL CONTINUE. DCAPE TRENDS HAVE ALSO STARTED GOING DOWN. HOWEVER...THE CONVECTION AHEAD OF THE LINE IS PICKING UP IN INTENSITY ESPECIALLY ACROSS NORTHEAST GEORGIA AND THE UPSTATE. EXPECT THAT WE WILL LIKELY SEE A FEW MORE WARNINGS BEFORE ALL IS SAID AND DONE...WITH WIND DAMAGE THE MAIN THREAT. AT 230 PM EDT MONDAY...AN AMPLIFYING UPPER TROUGH AND AN APPROACHING COLD FRONT WILL SUPPORT CONVECTIVE DEVELOPMENT THIS AFTERNOON AND EVENING...AND AGAIN ON TUESDAY. ALTHOUGH INSTABILITY WILL EXCEED 1000 J/KG EACH AFTERNOON...SHEAR WILL BE MODEST...AND ORGANIZED STORM WILL NOT BE LIKELY. LIMITED INSTABILITY OVERNIGHT WILL ALLOW FOR WEAK CONVECTION TO PERSIST. WITH THE ATMOSPHERIC COLUMN BECOMING MORE MOIST...GREATER PRECIPITATION RATES CAN BE EXPECTED...BUT ENOUGH STEERING FLOW SHOULD BE PRESENT TO KEEP CELLS MOVING. TEMPERATURES WILL EXHIBIT A REDUCED DIURNAL RANGE DUE TO CLOUDS AND MOISTURE. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... AS OF 155 PM MON...SFC COLD FRONT MOVES EAST OF THE AREA TUE NITE TAKING THE DEEP MOISTURE AND FORCING WITH IT. STILL EXPECT SOME LINGERING CONVECTION THRU THE EVENING BEFORE THE ACTIVITY MOVES OUT. CANNOT RULE OUT A LINGERING SVR STORM OR TWO SOUTH OF I-85 EARLY IN THE EVENING AS WELL. COOLER AND DRIER HIGH PRESSURE BUILDS IN ON WED AND REMAINS IN PLACE ON THU AS A RELATIVELY DEEP UPPER TROF BUILDS OVER THE ERN CONUS. WED SHUD BE DRY...BUT CANNOT RULE OUT SOME ISOLATED CONVECTION OVER THE HIGHER TERRAIN ON THU...BUT CHC IS QUITE LOW. HIGHS NEAR OR A LITTLE BELOW NORMAL WED...WILL FALL A COUPLE OF DEGREES THU. NEAR NORMAL LOWS TUE NITE WILL FALL TO A LITTLE BELOW NORMAL WED NITE. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 200 PM MONDAY...STARTING AT 00Z FRIDAY...500MB PATTERN HAS A TROUGH WITH AXIS OVER THE EASTERN SEABOARD AND A RIDGE OVER NEW MEXICO. THE SOUTHERN PORTION OF THE EAST COAST TROUGH IF FORECAST SEPARATE FROM THE MAIN FLOW WHICH REMAINS OVER NEW ENGLAND. THIS SOUTHERN PORTION ELONGATES THROUGH THE WEEKEND AND IS NOW FORECAST TO BREAK OFF INTO A CUT OFF LOW SUNDAY NIGHT OR MONDAY TO BE CENTERED OVER THE TEXAS COAST. THE ECMWF ALSO HAS ANOTHER CUT OFF LOW OVER NEW ENGLAND ON MONDAY. THE SW RIDGE MOVES WEST OVER SRN CALIFORNIA ON MONDAY WHILE THE GENERAL UPPER FLOW IS WEST TO EAST ACROSS THE NATION. AT THE SURFACE...OUR REGION WILL BE UNDER A 1020 HIGH CENTERED OVER CENTERED OVER THE SW VA AND NC MTNS. A STATIONARY FRONT REMAINS FROM THE NORTHERN GULF ACROSS NRN FL TO THE OFFSHORE WATERS EAST OF THE CAROLINAS. THE FRONT WILL SLOWLY DISSIPATE DURING THIS EXTENDED FORECAST PERIOD. ENOUGH MOISTURE SHOULD BE AVAILABLE COMBINED WITH DIFFERENTIAL HEATING IN THE MOUNTAINS AND PERHAPS SOME OCCASIONAL LOW LEVEL UPSLOPE WILL PRODUCE A FEW SHOWERS AND THUNDERSTORMS FAVORING LOCATIONS NEAR THE BLUE RIDGE. SEEMS THE MOST FAVORABLE TIME FOR UPSLOPE IS LATE FRIDAY WITH 925MB FLOW FROM THE EAST OVER THE PIEDMONT AND LIGHT SE FLOW TOWARD MTNS. TEMPS ABOUT A CATEGORY BELOW NORMAL FRIDAY AND SLOWLY RISING TO NORMAL OR EVEN SLIGHTLY ABOVE EARLY NEXT WEEK. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AT KCLT...A MIXTURE OF VFR/MVFR THROUGH THE TAF CYCLE. INITIALIZED TAF VFR THROUGH THE EARLY MORNING BEFORE INTRODUCING MVFR CIGS AS LOW CLOUDS ADVECT NORTHWARD OUT OF THE SC UPSTATE AROUND 10Z. WINDS WILL LIKELY REMAIN SW AT AROUND 4-6KTS WHICH SHOULD BE ENOUGH TO INHIBIT ANY FOG DEVELOPMENT. THAT SAID...SOME GUIDANCE SOURCES DID INDICATE 4-5SM BR AROUND DAYBREAK THEREFORE WILL CONTINUE TO MONITOR SUCH AND MAKE AMD LATER IF NEEDED. OTHERWISE...MVFR CIGS WILL RAISE TO LOW VFR BY LATE MORNING AHEAD OF AN INTRUDING COLD FRONT FROM THE WEST. CONTINUED WITH PREVIOUS MVFR PROB30 WITH MINOR TIMING TWEAKS TO ACCOUNT FOR ANY FROPA ASSOCIATED SHRA/TSRA DURING THE EARLY AFTERNOON...WITH CLEARING EXPECTED QUICKLY POST FROPA ALONG WITH NORTHERLY VEERED WINDS. ELSEWHERE...MUCH THE SAME AS KCLT ABOVE BIG PICTURE WISE...HOWEVER WITH ALTERATIONS ON THE DETAILS. ALL SITES WILL SEE RESTRICTIONS THIS MORNING IN THE FORM OF BOTH BR/CIGS. CARRIED MVFR/IFR RESTRICTIONS AT KAVL WITH A TEMPO FOR SUCH AT KHKY PER GUIDANCE. KEPT CONDITIONS AT MVFR FOR THE SC SITES...HOWEVER DID INTRODUCE IFR SCT DECK AT KAND MID MORNING. OTHERWISE...ALL SITES INDICATE FROPA ASSOCIATED SHRA/TSRA ON TUESDAY WITH TIMING ADJUSTMENTS FOR EACH SITE PER LATEST CAM GUID...WITH CLEARING EXPECTED BEHIND THE FRONT. OUTLOOK...INTRUDING HIGH PRESSURE WILL YIELD DRIER/VFR CONDITIONS THRU WEEKS END WITH THE POSSIBLE EXCEPTION OF EARLY MORNING FOG/STRATUS IN THE MOUNTAINS. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT HIGH 85% HIGH 89% HIGH 100% HIGH 100% KGSP MED 73% HIGH 95% HIGH 100% HIGH 100% KAVL LOW 52% MED 70% HIGH 100% HIGH 100% KHKY MED 69% MED 79% HIGH 100% HIGH 100% KGMU MED 79% HIGH 91% HIGH 100% HIGH 100% KAND HIGH 81% HIGH 91% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...CDG/TDP SHORT TERM...RWH LONG TERM...DEO AVIATION...CDG  FXUS62 KGSP 160708 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 308 AM EDT SUN AUG 16 2015 .SYNOPSIS... WEAK HIGH PRESSURE WILL LINGER OVER THE AREA TODAY BEFORE A WEAK COLD FRONT APPROACHES FROM THE NORTHWEST MONDAY. THIS FRONT WILL WASH OUT ACROSS THE AREA ON TUESDAY. ANOTHER COLD FRONT IS EXPECTED TO APPROACH BY THURSDAY AND BRING INCREASED CHANCES OF WIDESPREAD SHOWERS AND THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... THROUGH DAYBREAK...EXPECT PATCHY FOG TO DEVELOP NEAR AREAS WHERE SHOWERS FELL YESTERDAY AFTERNOON/EVENING...PARTICULARLY IN THE MTN VALLEYS. CANNOT RULE OUT AN ISOLATED SHOWER REDEVELOPING NEAR THE BLUE RIDGE OR TO THE EAST...AS A WEAK BOUNDARY IS LURKING. PERSISTENCE LOOKS LIKE A GOOD FCST FOR THE NEXT 24 HOURS AS WE REMAIN IN A COL REGION OF SORTS...DEVOID OF ANY MEANINGFUL MID/UPPER FORCING. HEIGHTS MAY RISE A BIT TODAY WITH SOME SLIGHTLY WARMER AIR ALOFT...WHICH WOULD CUT DOWN A BIT ON INSTABILITY. HOWEVER...PRECIP COVERAGE THE LAST TWO DAYS HAS BEEN BETTER THAN SHOWN BY THE MODELS...SO TAKING THAT INTO ACCT SUGGESTS NUDGING THE PRECIP CHANCES UP JUST A BIT...ESPECIALLY E OF THE MTNS. HEAVY RAIN AND FLASH FLOODING MIGHT BE A SLIGHTLY BIGGER THREAT THAN SEVERE WIND GUSTS BECAUSE OF VERY SLOW STORM MOTION...BUT EVEN THAT IS NOT ALL THAT GREAT AS PW AND WARM CLOUD DEPTH WILL STILL BE LACKING. THE SHOWER/STORM ACTIVITY SHOULD SLOWLY WANE THIS EVENING. TEMPS SHOULD BE FAIRLY CLOSE TO NORMAL ONCE AGAIN. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 245 AM EDT SUNDAY...THE SHORT TERM BEGINS WITH A CONTINUED WEAKNESS IN THE FLOW ALOFT...AND MOIST SOUTHERLY FLOW AROUND THE WESTERN PERIPHERY OF A SURFACE HIGH PRESSURE IN THE ATLANTIC. AFOREMENTIONED WEAKNESS IS MAINLY CENTERED ON A VORT LOBE HOVERING OVER THE MID MISSISSIPPI VALLEY...BUT GETS ABSORBED BY THE LONGWAVE TROUGH UP ALONG THE US/CANADA BORDER THROUGH THE SHORT TERM. MEANWHILE A MORE POTENT SHORTWAVE DIPS INTO THE NORTHERN PLAINS. THIS USHERS IN A BIT OF A PATTERN CHANGE FOR THE FORESEEABLE FUTURE...WITH INCREASING MOISTURE LEADING TO INCREASINGLY UNCOMFORTABLE AFTERNOONS AND AT LEAST AN ENHANCED DIURNAL TREND IN THUNDERSTORM ACTIVITY. NOT MUCH IN THE WAY OF SURFACE FEATURES TO POINT AT THROUGH THE PERIOD...RATHER WE ARE LOOKING AT WEAK GENERAL SYNOPTIC LIFT AND RAPIDLY INCREASING MOISTURE. GUIDANCE HAS SEEMED TO SLOW DOWN THE INCREASE IN POPS JUST A TAD...WITH A TIGHT GRADIENT OF POPS ON MONDAY /BEST CHANCES WEST/...BUT TUESDAY THE DEEP-LAYER MOISTURE MOVES RIGHT OVER THE AREA AND LIKELY POPS ARE WARRANTED ACROSS MOST OF THE AREA. WILL PROBABLY NEED TO INCREASE THESE IN SUBSEQUENT UPDATES TO CATEGORICAL. WHILE ISOLATED STRONG TO POSSIBLY SEVERE THUNDERSTORMS CANNOT BE RULED OUT /IT IS SUMMERTIME AFTER ALL/...THE BIGGER CONCERN IS THE HEAVY RAIN THREAT WITH PW VALUES HOVERING AT OR JUST ABOVE 2 INCHES /NOT FAR FROM THE CLIMATOLOGICAL MAX/ AND LITTLE TO NO FLOW ALOFT. WE DO NEED THE RAIN OF COURSE AND FOR NOW BEST CHANCES OF HEAVY RAIN SEEM TO BE CENTERED ACROSS NORTHEAST GEORGIA AND THE UPSTATE...AREAS THAT IN GENERAL CAN HANDLE MORE RAIN. THE OTHER UPSIDE TO THIS IS THAT WIDESPREAD CLOUD COVER SHOULD KEEP TEMPERATURES DOWN...WITH NEW GUIDANCE HOVERING IN THE MID-80S FOR HIGHS TUESDAY ACROSS THE UPSTATE AND PIEDMONT...AND MANY AREAS IN THE MOUNTAINS NOT GETTING OUT OF THE 70S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 300 AM EDT SUNDAY...UNSEASONABLY MOIST PATTERN REMAINS IN PLACE THROUGH THE PERIOD AS A REINFORCING SHORTWAVE DIVES DOWN THE LONGWAVE TROUGH ACROSS THE NORTHERN PLAINS...INCREASING THE AMPLITUDE OF THE WAVETRAIN AND RESULTING SOUTHWEST FLOW ALOFT OVER THE SOUTHEAST. BY THURSDAY INTO FRIDAY...THE UPPER TROUGH LIFTS BACK UP INTO CANADA ALLOWING THE ATTENDANT SURFACE FRONT TO ELONGATE DOWN THE EASTERN SEABOARD AND GULF COAST STATES...KEEPING THE WARM MOIST REGIME IN PLACE. PW VALUES CONTINUE TO HOVER NEAR 2 INCHES WITH LITTLE TO NO FLOW ALOFT...AND THIS COMBINED WITH POTENTIAL FOR AT LEAST ISOLATED HEAVY RAIN IN THE SHORT TERM COULD LEAD TO A LINGERING THREAT FOR ISOLATED FLASH FLOODING. TEMPERATURES GRADUALLY INCREASE THROUGH THE PERIOD BUT REMAIN NEAR NORMAL FOR HIGHS...WITH LOWS LINGERING JUST ABOVE SEASONAL NORMALS DUE TO THE HIGH AMOUNTS OF MOISTURE. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... AT KCLT...A FEW SHOWERS WERE KICKING AROUND NEARBY...SO A VCSH WAS INCLUDED TO START WITH. FOR THE REST OF THE PRE-DAWN HOURS...WILL BE KEEPING AN EYE ON FOG DEVELOPMENT ACROSS THE PIEDMONT. SOME LOCATIONS ALREADY HAD REDUCED VSBY. DEWPT DEPRESSION STILL 4-5 DEGREES SO NOTHING IS IMMINENT...BUT GUIDANCE IS HITTING IT A BIT MORE THAN PREVIOUS NIGHTS. HAVE INCLUDED AN MVFR AFTER 10Z WITH THE EXPECTATION THAT EXISTING FOG WILL EXPAND ACROSS METRO CLT. THE FOG SHOULD BE SHORT LIVED. OTHERWISE...EXPECT TODAY TO BE VERY SIMILAR TO YESTERDAY AND THE DAY BEFORE...MEANING SOME HIGH BASED CU FORMING WITH SOME DAYTIME HEATING...THEN A SHOWER CHANCE IN THE AFTERNOON/EVENING. CONFIDENCE ONLY HIGH ENOUGH FOR A VCSH AT THIS TIME. WIND SPEED WILL ONCE AGAIN BE LESS THAN 5KT...WHILE WIND DIRECTION WILL BE CONFOUNDING ONCE AGAIN...DOMINATED MAINLY BY CONVECTIVE OUTFLOWS. ELSEWHERE...VALLEY FOG AND STRATUS IS EXPECTED TO DEVELOP OVER KAVL TONIGHT...THEN BURN OFF/DISSIPATE BY 13Z OR SO. THE REST OF THE TAF SITES WILL LIKELY REMAIN VFR THRU THE PERIOD...APART FROM AFTERNOON SHOWERS AND THUNDERSTORMS. COVERAGE HAS BEEN GREATER THAN EXPECTED THE LAST FEW DAYS SO GOING WITH A PERSISTENCE FCST SUGGESTS INCLUDING A PROB30 AT MOST OF THE TAF SITES. EXPECT A LIGHT/VARIABLE WIND. OUTLOOK...DIURNAL SHRA/TSRA CHANCES WILL INCREASE FOR MONDAY AND TUESDAY...AS MOISTURE AND INSTABILITY INCREASE. THE BEST CHANCES ONCE AGAIN WILL BE OVER THE MOUNTAIN RIDGES. EARLY MORNING FOG/STRATUS WILL ALSO BE A CONCERN IN THE MTN VALLEYS. CONFIDENCE TABLE... 07-13Z 13-19Z 19-01Z 01-06Z KCLT HIGH 96% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 96% KHKY HIGH 93% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 96% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...TDP NEAR TERM...PM SHORT TERM...TDP LONG TERM...TDP AVIATION...PM  FXUS62 KGSP 301745 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1245 PM EST Thu Nov 30 2017 .SYNOPSIS... A cold front will approach the region from the northwest today and settle south of the area on Friday. Moisture may briefly return over the front early this weekend, but then dry high pressure will redevelop Sunday through Monday. A stronger cold front will approach our region from the west by the middle of next week. && .NEAR TERM /THROUGH FRIDAY/... As of 1245 PM EST Thursday: Isolated showers will move across NE GA and the southern Upstate early this afternoon. Expect coverage to increase across the mountains, NE GA, and the Upstate late this afternoon into the evening as a weak frontal system approaches from the west. The associated short wave is weak as well, keeping overall forcing limited. The band of deep moisture associated with the system is also narrow with little to no Gulf inflow, also limiting precip chances. Kept likely PoP confined to the TN border counties where westerly upslope flow will help maximize precip chances. Chance PoP for NE GA and the western Upstate. I-40 corridor has the lowest chance of seeing any precip where moisture inflow is least and flow turns downslope more quickly. Expect only isolated showers for the CLT metro. QPF will be light across the mountains and very light elsewhere. Lows tonight will be 10 to 15 degrees above normal with the clouds and weak WWA ahead of the front. Any precip tapers off quickly as the front moves east of the area Friday. There could be some lingering moisture keeping lower clouds over the area through the morning. High pressure builds in from the north, but temps remain nearly steady as any cool air is delayed. Highs will be 5 to 10 degrees above normal outside of the mountains and around 5 degrees above normal across the mountains. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 200 AM EST Thursday: Broad ridging will build over the region from the west Friday through Friday night before additional shortwaves cross the area in increasingly zonal flow aloft on Saturday. Although mid and upper drying should occur behind the cold front settling southeast of our area during this period, 850 mb moisture will linger over the region and moist upglide will likely redevelop Friday night into Saturday as 1028 mb surface high pressure sets up to the north. Fairly abundant clouds should result but precipitation looks much less certain. Any QPF will be light through Saturday, with the best chances over the southern half. Temperatures should dip sharply back toward, or slightly below, climo - especially for Saturday afternoon maximum temperatures. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 215 AM EST Thursday: Stronger ridging will build over the eastern CONUS on Sunday before the ridge axis moves off the east coast late Monday. Major height falls will set up across the Canadian/U.S. Rockies early next week - with a prominent trough crossing the plains Tuesday and bottoming out over the OH/MS River Valleys on Wednesday. An associated cold front will push eastward toward the Appalachians through this period, with deeper moisture arriving from the west on Tuesday and likely crossing our forecast area Tuesday night through Wednesday. The best southwesterly low level jet should ramp up Tuesday night ahead of the boundary and bring a local focus of heavier QPF to the southern/southwestern mountains. Instability looks rather limited while deep layer shear could reach 50 to 60 kt with the fropa. Will keep thunder out of the forecast for now given the fairly modest lapse rates. Cannot rule out a late day Wednesday mixover to snow showers in the higher terrain of the western mountains as northwest upslope flow develops and the colder air begins spilling in. This will herald the onset of a major pattern change for the eastern U.S. developing just beyond the current extended period late next week when much colder temperatures are likely to arrive. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... At KCLT and Elsewhere: VFR conditions expected into the evening. However, there will be some lower VFR stratocu floating around through the day with those clouds becoming cigs by evening at the western sites. Showers more likely across the western sites as well this evening as the weak front moves through. Generally SW winds today become light and variable overnight. MVFR conditions likely overnight with vsby and cigs about equal chances. IFR probable for the western sites so have TEMPO for those. IFR and precip least likely at KHKY and less likely at KCLT. Conditions should clear out after daybreak as high pressure builds in. However, some lingering low VFR clouds possible. Winds become NE and increase in speed through the morning. Outlook: High pressure remains in place through the weekend. That said, remnant low level moisture in the vicinity could lead to restrictive conditions on Saturday and possibly Sunday as moist upglide is favorable. Restrictions and precip may return by mid week as a cold front moves in from the west. Confidence Table... 17-23Z 23-05Z 05-11Z 11-12Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 95% High 94% KAVL High 100% High 100% Med 78% Low 54% KHKY High 100% High 100% High 100% High 83% KGMU High 100% High 100% High 90% High 94% KAND High 100% High 100% Med 63% Low 52% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables and ensemble forecasts are available at the following link: www.weather.gov/gsp/aviation && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...HG NEAR TERM...RWH SHORT TERM...HG LONG TERM...HG AVIATION...RWH