FXUS62 KRAH 161442 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 940 AM EST SAT NOV 16 2013 .SYNOPSIS... WEAK HIGH PRESSURE WILL EXTEND ACROSS CENTRAL NC TODAY THEN DRIFT EAST TONIGHT AND SUNDAY. A STRONG COLD FRONT WILL APPROACH FROM THE WEST SUNDAY AND CROSS OUR AREA SUNDAY NIGHT THROUGH EARLY MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 AM SATURDAY... REST OF TODAY: AS THE PREVIOUS SHIFT NOTED... THE BIGGEST CHALLENGE TODAY IS THE EXTENT OF CLOUD COVER AND ITS EFFECTS ON TEMPS. THE 12Z GSO SOUNDING SHOWED DEEP NEAR-SATURATION EXTENDING UP TO 650 MB... AND AREA PILOT REPORTS THIS MORNING INDICATE CLOUD DEPTHS UP TO 3K FT. TRIAD FORECAST SOUNDINGS FROM RECENT RAP MODEL RUNS DID NOT DEPICT THE CLOUD DEPTH WELL (LITTLE TOO DRY ABOVE 850 MB)... ALTHOUGH THE UPSTREAM 12Z FFC SOUNDING DOES SUGGEST WE'LL SEE SOME DRYING ALOFT (ABOVE 900 MB) THROUGH THE DAY. THE VERY LIGHT NEAR-SURFACE WINDS ALONG WITH THE STABILITY OF THE LOWEST 50-100 MB WILL LIMIT VERTICAL AND HORIZONTAL MIXING HOWEVER WITH THIS AIR MASS BANKED UP AGAINST THE HIGHER TERRAIN... AND EXPECT THAT THESE CLOUDS WILL HOLD FIRM FOR MUCH OF THE DAY ACROSS OUR WRN CWA. THE LIGHTER WINDS IN THE ERN CWA WILL DISCOURAGE MIXING EVEN MORE... AND A RECENT AMDAR AIRCRAFT SOUNDING FROM RDU SHOWS THE MOIST LAYER STRETCHING UP TO 750 MB... SO THE FEW BREAKS AND THIN SPOTS CURRENTLY OVER THE CENTRAL/ERN PIEDMONT MAY BE THE PEAK OF SUNSHINE UNTIL LATER THIS AFTERNOON (AFTER 3 PM). ALL OF THIS SHOULD PUT A DAMPER ON TEMPS... AND BASED ON THE LATEST READINGS... WE MAY ONLY SEE READINGS CLIMB ANOTHER 10 OR SO DEGREES THROUGH THE DAY. WILL NUDGE HIGHS SLIGHT DOWNWARD IN THE WEST AND UPWARD IN THE EAST AND SOUTH (WHICH IS SEEING THE MOST SUNSHINE THIS MORNING). HIGHS 62 NW TO 72 EAST. -GIH TONIGHT...LIGHT/NEAR CALM WIND REGIME AND PLENTY OF MOISTURE IN THE LOWEST 5K-8K FT SUGGEST A RETURN OF LOW OVERCAST WITH THE POTENTIAL FOR AREAS OF FOG. COULD SEE SOME DRIZZLE THEN ISENTROPIC LIFT MARGINAL AT BEST. THE MODIFYING AIR MASS AND EXTENSIVE CLOUD COVER WILL MAINTAIN RELATIVELY MILD OVERNIGHT TEMPS FOR THIS TIME OF YEAR. MIN TEMPS GENERALLY IN THE LOWER 50S. -WSS && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 315 AM SATURDAY... SUNDAY...S/W RIDGE EXITS OUR REGION EARLY SUNDAY. THIS WILL ALLOW A S/W IN THE NORTHERN STREAM TO PROGRESS E-NE FROM THE CENTRAL-NORTHERN PLAINS INTO THE WESTERN LAKES BY EARLY SUNDAY EVENING. THE SFC COLD FRONT ATTENDANT WITH THE S/W SHOULD STRETCH FROM LAKE MICHIGAN SSW TO NEAR MEMPHIS. THE APPROACH OF THIS FRONTAL SYSTEM WILL INDUCE AND STRENGTHEN A SLY FLOW ACROSS CENTRAL NC BY SUNDAY AFTERNOON. WHILE CLOUDINESS WILL BE QUITE EXTENSIVE...THE WARM SLY FLOW SHOULD BOOST TEMPS INTO THE 70-75 DEGREE RANGE. IF A FEW RENEGADE SHOWERS WERE TO OCCUR SUNDAY AFTERNOON ACROSS THE WEST...THESE SHOWERS MAY KNOCK TEMPS DOWN A FEW DEGREES. OTHERWISE RAIN CHANCES THROUGH SUNSET APPEAR MINIMAL. SUNDAY NIGHT...ATMOSPHERE WILL BE CHARACTERIZED AS A HIGH SHEAR/LOW CAPE ENVIRONMENT AS A STRENGTHENING LOW LEVEL JET WILL CROSS OUR REGION OVERNIGHT. THIS WILL RESULT IN BULK SHEAR VALUES INT HE 35-50KT RANGE...SUPPORTIVE OF ORGANIZED CONVECTION. CURRENTLY MODEL INSTABILITY LACKING WITH MUCAPE VALUES NO WORSE THAN 250-300 J/KG EXPECTED. REVIEW OF GFS BUFKIT SOUNDING DEPICT A RATHER EXTENSIVE WARM LAYER IN THE 850-700MB LAYER. MID LEVEL LAPSE RATES APPEAR TO BE NO WORSE THAN 5.5 DEG C/KM. DO WONDER IF MODEL INSTABILITY MAY BE UNDERDONE AS SFC DEWPOINTS HAVE THE POTENTIAL TO RECOVER INTO THE LOW-MID 60S OVER MOST OF CENTRAL NC. THUS CANNOT TOTALLY RULE OUT THE POSSIBILITY OF A STRONG OR SEVERE STORMS OVERNIGHT SUNDAY NIGHT. HOWEVER...SUCH OCCURRENCE APPEARS TO BE VERY LIMITED AT THIS TIME SO REFRAIN FROM MENTIONING THUNDER AT THIS TIME AND AWAIT LATER MODEL GUIDANCE/UPDATES. APPEARS TO BE FAIRLY DEEP LIFT WITH THE FRONT AND MOISTURE PLENTIFUL. HAVE INCREASES POPS TO LIKELY OR LOW END CATEGORICAL ACROSS THE REGION SUNDAY AS TH SFC FRONT SHOULD BE ON OUR WESTERN PERIPHERY PRIOR TO DAYBREAK MONDAY. VERY MILD SUNDAY NIGHT WITH MIN TEMPS NEAR 60 NW TO LOW-MID 60S ELSEWHERE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 315 AM SATURDAY... MONDAY AND MONDAY NIGHT: THE SURFACE COLD FRONT MENTIONED IN THE SHORT TERM IS EXPECTED TO CROSS CENTRAL NC MONDAY MORNING INTO THE EARLY AFTERNOON... WITH THE BEST CHANCE FOR SHOWERS... AND PERHAPS EVEN A FEW STORMS... IN ADVANCE OF THE FRONT. FOR NOW... WILL SHOW THE HIGHEST POPS ACROSS EASTERN AND SOUTHEASTERN PORTIONS OF THE AREA FOR THE MORNING (SLIGHT CHANCE NW TO LIKELY E/SE)... WITH ONLY A LINGERING CHANCE IN OUR FAR EAST/SOUTHEAST BY AFTERNOON. THE MAIN DYNAMICS ARE EXPECTED TO PASS WELL TO THE NORTH OF THE AREA. GIVEN THIS AND THE TIME OF DAY (MORNING) ALONG WITH THE GOOD LOW LEVEL JET PROGGED TO BE TO THE EAST OF CENTRAL NC BY 12Z MONDAY... WE DO NOT ANTICIPATE ANY SEVERE WEATHER. THE GOOD PUSH OF COLD AIR IS EXPECTED TO LAG THE FRONT THOUGH... WITH DOWNSLOPE FLOW ON MONDAY. GIVEN THE DOWNSLOPE FLOW AND QUICKLY CLEARING SKIES BEHIND THE FRONT... ALONG WITH TEMPS STARTING OUT GENERALLY IN THE 60S ACROSS THE AREA... EXPECT HIGH TEMPS WILL BE AROUND 70 NORTHWEST TO THE MID 70S... MAYBE EVEN UPPER 70S... SOUTHEAST. HIGH PRESSURE WILL BUILD INTO THE AREA ON MONDAY NIGHT WITH LOW TEMPS DRIVEN BY CAA. LOWS ON TUESDAY MORNING ARE EXPECTED TO RANGE FROM THE UPPER 30S NORTH TO LOWER 40S SOUTH... WITH A NORTHWESTERLY TO NORTHERLY WIND. TUESDAY THROUGH FRIDAY: SURFACE HIGH PRESSURE CENTERED ACROSS THE OHIO VALLEY/GREAT LAKES REGION START THE PERIOD IS EXPECTED TO MOVE EASTWARD AND OFF THE NORTHEAST/NEW ENGLAND COAST BY THURSDAY... WHILE EXTENDING SOUTHWARD INTO CENTRAL NC. A LOW AMPLITUDE FLOW ALOFT WILL PERSIST ACROSS THE REGION GENERALLY THROUGH THE REMAINDER OF THE FORECAST PERIOD... ALTHOUGH HEIGHTS ALOFT WILL SLOWLY RISE THROUGH THIS TIMEFRAME. MEDIUM RANGE MODELS ARE STRUGGLING HOW TO HANDEL THE EVOLUTION OF THE LARGE SCALE FLOW PATTERN THOUGH... AT THE END OF THE FORECAST PERIOD. NEAR THE END OF THE PERIOD MEDIUM RANGE MODELS BEGIN TO TREND TO AN ERN PAC/WEST COAST RIDGE AND DOWNSTREAM TROUGHING PATTERN. FOR NOW IT APPEARS THAT ANY SYSTEM ASSOCIATED WITH THIS NEXT APPROACHING TROUGH WILL HOLD OFF UNTIL BEYOND THE MEDIUM RANGE. THUS... FOR US WE SHOULD SEE DRY CONDITIONS FOR THE REMAINDER OF THE WEEK WITH SLOWLY MODERATING TEMPS. HOWEVER... SKIES WILL BE SUNNY TO START THE PERIOD... THEN TRANSITION TO PARTLY TO MOSTLY CLOUDY WITH BOTH INCREASING HIGH LEVEL MOISTURE LATE WEEK FROM THE WEST ALONG WITH EASTERLY FLOW ADVECTING IN MOISTURE OFF THE ATLANTIC ON THURSDAY INTO FRIDAY AS THE SURFACE HIGH SHIFTS OFFSHORE. HIGH TEMPS GENERALLY BE IN THE 50S... WITH LOWS RANGING FROM GENERALLY 30 TO 40 DEGREES... COLDEST ON WEDNESDAY MORNING (WHERE A FEW UPPER 20S CANT BE RULED OUT). && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 645 AM SATURDAY... WIDESPREAD LOW END MVFR/IFR CEILINGS ACROSS CENTRAL NC WITH POCKETS OF MVFR VISIBILITY DUE TO FOG WILL PERSIST ACROSS CENTRAL NC UNTIL 14Z. AFTER WHICH...VISIBILITIES WILL IMPROVE TO GREATER THAN 6 MILES AND CEILINGS WILL GRADUALLY LIFT THOUGH REMAIN IN THE MVFR RANGE UNTIL 18Z-20Z. BY MID AFTERNOON...EXPECT CEILINGS TO CONTINUE TO LIFT AND EVENTUALLY SCATTER AT MOST SPOTS WITH CLOUD BASES 3000-4000FT. THE LOWER LAYERS OF THE ATMOSPHERE WILL REMAIN MOIST LATE TODAY THROUGH TONIGHT. WITH LITTLE MIXING ANTICIPATED...EXPECT CEILINGS TO LOWER SHORTLY AFTER SUNSET WITH WIDESPREAD LOW END MVFR/IFR CEILINGS ANTICIPATED THIS EVENING AND PERSISTING INTO SUNDAY MORNING. AGAIN...EXPECT A GRADUAL IMPROVEMENT IN CEILINGS LATE SUNDAY MORNING INTO SUNDAY AFTERNOON. AN APPROACHING COLD FRONT WILL INCREASE THE THREAT FOR SHOWERS AND ASSOCIATED MVFR VISIBILITIES...ESPECIALLY SUNDAY NIGHT THROUGH EARLY MONDAY. SOUTHERLY SFC WINDS WILL BECOME BREEZY AHEAD OF THE FRONT LATE SUNDAY INTO SUNDAY NIGHT WITH SUSTAINED WINDS 10-15KTS AND GUST 20-25KTS PROBABLE SUNDAY NIGHT. THE COLD FRONT WILL SWEEP THROUGH CENTRAL NC MONDAY MORNING. BEHIND THE FRONT...MUCH DRIER AIR WILL QUICKLY DIMINISH THE SHOWERS AND DISSIPATE THE CLOUD COVERAGE. VFR CONDITIONS SHOULD COVER CENTRAL NC MONDAY AFTERNOON AND PERSIST THROUGH WEDNESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS  FXUS62 KRAH 141456 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1055 AM EDT MON APR 14 2014 .SYNOPSIS...SOUTHERLY FLOW WILL ADVECT AN INCREASINGLY MOIST AND UNSTABLE AIRMASS INTO THE REGION TODAY AND TONIGHT AS A POTENT UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT TRACK EAST INTO THE TENNESSEE VALLEY. THE COLD FRONT WILL PROGRESS EAST THROUGH THE CAROLINAS TUESDAY AFTERNOON AND EVENING. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1055 AM MONDAY... THE 12Z KGSO SOUNDING WAS CAPPED TO DEEP CONVECTION WITH A GOOD CAP BETWEEN 850MB AND 700MB...AND CONSIDERABLE MOISTURE ABOVE 500MB. THE LATEST SPC MESOANALYSIS SHOWED A RELATIVE MINIMUM OF PRECIPITABLE WATER VALUES OVER MUCH OF CENTRAL NORTH CAROLINA ALTHOUGH WITH A NARROW RIBBON OF INCREASING VALUES...JUST BELOW AN INCH...EXTENDING FROM SOUTH CAROLINA INTO THE SOUTHWEST PIEDMONT. HIGH PRESSURE EXTENDING OVER CENTRAL NORTH CAROLINA FROM THE EAST WAS PROVIDING A MOIST...SOUTHERLY FLOW OFF OF THE ATLANTIC INTO THE AREA...WITH SURFACE DEW POINTS IN THE MID 50S TO AROUND 60. TO OUR WEST...THE SURFACE LOW WILL INCREASE IN STRENGTH DUE TO THE OFFSET UPPER LEVEL TROUGH TO THE WEST. DIVERGENCE ALOFT IS DECREASING THE SURFACE PRESSURE AHEAD OF THE FRONT BRINGING IN CYCLONIC VORTICITY ADVECTION IN A SHORT WAVE AHEAD OF THE FRONT. SURFACE WINDS ARE SOUTHERLY AND HAVE INCREASED THE DEWPOINTS AS MOIST AND WARM AIR IS ADVECTED INTO THE AREA AHEAD OF THE COLD FRONT. WARM ADVECTION ALONG WITH CYCLONIC VORTICITY ADVECTION WILL BRING AN INCREASE IN LIFT AND CLOUD COVER OVER THE AREA AND AN INCREASED CHANCE FOR PRECIPITATION AND CONVECTION. A FEW SHOWERS ARE POPPING UP TO OUR WEST AND ARE EXPECTED TO INCREASE IN NUMBER AND EVENTUALLY PRODUCE CONVECTIVE STORMS AS THE COLD FRONT MOVES EASTWARD. THE 12Z UPPER-AIR ANALYSIS SHOWED SOME DIFFLUENCE TO OUR WEST AND THIS IS FORECAST TO CONTINUE THIS AFTERNOON INTO TONIGHT AS A SERIES OF MID-LEVEL WAVES MOVE THROUGH CENTRAL NORTH CAROLINA. THE LATEST RAP SHOWS THE MID-LEVEL CAP WEAKENING WITH TIME THROUGH EARLY AFTERNOON...AND SLIGHT 700MB COOLING ON THE 12Z UPPER-AIR ANALYSIS WOULD SUGGEST THIS...ALTHOUGH THE RAP ALSO FORECASTS A MODEST INCREASE IN THOSE MID-LEVEL TEMPERATURES LATE IN THE DAY. WITH THE MOISTURE IN PLACE...MODEST INSTABILITY WITH SURFACE-BASED CAPE AROUND 400J/KG AND MLCAPE IN THHIGHS TODAY WERE LOWERED ABOUT A DEGREE IN THE TRIAD DUE TO EXPECTED CLOUD COVER...AND RAISED ABOUT A DEGREE TOWARD INTERSTATE 95 DUE TO THINNER CLOUDS FOR A LONGER PERIOD OF TIME THERE. E LOWEST KM AROUND 200J/KG...AND SOME LIFT WITH THE MID-LEVEL SHORTWAVES...AS THE CAP ERODES ANTICIPATE ISOLATED TO SCATTERED SHOWERS DEVELOPING...WITH AN ISOLATED THUNDERSTORM POSSIBLE. AS THE MID-LEVEL TEMPERATURES WARM SLIGHTLY LATER...THIS COULD FOR A TIME INHIBIT MORE DEEP CONVECTION...AND THIS SCENARIO IS NOTED BY MORE THAN ONE WRF MODEL AS WELL AS IMPLIED BY RAP QPF. MOISTENING OF THE UPPER LEVELS WILL INCREASE CLOUD DEPTH AND ALLOW FOR LIFTING OVER A DEEPER LAYER. THIS WILL INCREASE THE CHANCE FOR SOME DEEP MOIST CONVECTION AND SHOWERS OVER THE AREA... HOWEVER...THE STRONGEST LIFTING WILL STAY TO THE WEST WITH THE COLD FRONT. CONVECTION SHOULD BECOME MORE NUMEROUS IN COVERAGE OVER CENTRAL NORTH CAROLINA THIS EVENING INTO TONIGHT DUE TO ONGOING MOISTENING...STRENGTHENING HEIGHT FALLS...AND PERIODIC DPVA IN SW FLOW ALOFT...ESPECIALLY IN WESTERN PORTIONS OF THE STATE. HOWEVER...SEVERAL LARGE MESOSCALE CONVECTIVE SYSTEMS ARE EXPECTED TO DEVELOP UPSTREAM IN THE DEEP SOUTH IN THIS PERIOD...ONE THIS AFTERNOON AND PERHAPS ANOTHER LATE TONIGHT...AND HOW THESE FEATURES EVOLVE/INTERACT WITH THE LARGER SCALE PATTERN WILL MOST CERTAINLY AFFECT PRECIP CHANCES DOWNSTREAM IN CENTRAL NC...LENDING A FAIR AMOUNT OF UNCERTAINTY TO THE PRECISE COVERAGE/AMOUNT OF CONVECTION TONIGHT. THE INCREASED CLOUD COVER WILL RESULT IN A SLIGHT DECREASE...ROUGHLY A DEGREE...FOR HIGH TEMPERATURES FOR THE WESTERN PART OF CENTRAL NORTH CAROLINA. HIGHS WERE RAISED ABOUT A DEGREE TOWARD INTERSTATE 95 WHERE THERE WILL BE MORE PERIODS OF THINNER CLOUDS AND MORE SUNLIGHT HITTING THE GROUND. A VERY MOIST AND BREEZY SOUTHERLY FLOW THROUGHOUT THE WARM SECTOR IN THE CAROLINAS WILL MAINTAIN TEMPS IN THE MID 60S OVERNIGHT. THOUGH QUITE CONDITIONAL/UNCERTAIN...IF DEEP CONVECTION DEVELOPS AND PROGRESSES INTO CENTRAL NC THIS EVENING AND TONIGHT...AN ISOLATED SEVERE STORM WOULD BE POSSIBLE GIVEN INCREASINGLY IMPRESSIVE LOW/DEEP-LAYER SHEAR. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 330 AM MONDAY... TUE/TUE NIGHT: EXPECT CHANCES FOR CONVECTION NEAR 100% ON TUESDAY AS A POTENT UPPER LEVEL TROUGH AND ATTENDANT COLD FRONT PROGRESS THROUGH THE CAROLINAS IN THE PRESENCE OF A MOIST AND UNSTABLE AIRMASS VIA PERSISTENT SOUTHERLY LOW-LEVEL FLOW OFF THE ATLANTIC. AT THIS TIME...FROPA IS EXPECTED TO OCCUR BETWEEN 18-21Z IN THE NW PIEDMONT AND BY 00-03Z IN THE COASTAL PLAIN...WITH STRONG COLD ADVECTION THEREAFTER. EXPECT HIGHS RANGING FROM THE MID/UPPER 60S IN THE NW PIEDMONT WHERE CLOUD COVER/CONVECTION WILL PREVENT MUCH OF A RISE IN TEMPS PRIOR TO FROPA...TO THE MID/UPPER 70S POTENTIALLY IN THE COASTAL PLAIN WHERE FROPA WILL BE LATER. STRONG LOW/DEEP LAYER SHEAR...FAVORABLE DIURNAL TIMING...AND MARGINAL TO MODERATE DESTABILIZATION (500-1000 J/KG MLCAPE) CERTAINLY INDICATE A POTENTIAL FOR SEVERE THUNDERSTORMS...THOUGH THE PRECISE NATURE OF THE THREAT IS STILL DIFFICULT TO ASCERTAIN GIVEN A POTENTIAL FOR UPSTREAM CONVECTION /MCS ACTIVITY/ LATE TONIGHT AND TUE MORNING. DAMAGING WINDS AND ISOLD TORNADOES WILL BE THE PRIMARY THREAT(S)... THE LATTER OF WHICH COULD BE FURTHER ENHANCED BY BACKED SFC WINDS /LARGE CLOCKWISE CURVED HODOGRAPHS/ POSSIBLE ON THE EASTERN PERIPHERY OF ANY SFC WAVES WHICH COULD DEVELOP ALONG THE FRONT IN CENTRAL/EASTERN NC...PARTICULARLY ALONG AND EAST OF I-95 WHERE DIURNAL TIMING AND DESTABILIZATION WILL BE MOST FAVORABLE. STRONG COLD ADVECTION WILL RESULT IN A STARK CONTRAST IN TEMPERATURES IN COMPARISON TO THE PREVIOUS FEW DAYS...WITH LOWS RANGING FROM THE LOWER TO UPPER 30S...POTENTIALLY NEAR FREEZING ALONG/WEST OF HWY 1. A FREEZE WATCH MAY BE NEEDED FOR PORTIONS OF THE AREA TUE NIGHT/WED MORNING. SINCE LOWS WILL PRIMARILY DEPEND UPON COLD ADVECTION... SUFFICIENT UNCERTAINTY EXISTS TO PRECLUDE ANY FROST/FREEZE PRODUCT ISSUANCE AT THIS TIME. -VINCENT AS OF 245 AM MONDAY...RISING HEIGHTS ALOFT/DNVA AND ASSOCIATED STRONG SUBSIDENCE WILL RESULT IN FURTHER DEEP LAYER DRYING WED...FOLLOWED BY GENERALLY NEUTRAL VERTICAL MOTION BUT WITH STILL A RESIDUALLY DRY AND STRONGLY CAPPED REGIME OVER OUR REGION. SURFACE HIGH PRESSURE WILL CONSEQUENTLY BECOME UNSEASONABLY STRONG - INTO THE 1040-1045 MB RANGE AS IT BUILDS FROM THE OH VALLEY TO NEW ENGLAND. UNSEASONABLY COOL NORTHEASTERLY FLOW...WITH TEMPERATURES 10 TO 20 DEGREES BELOW AVERAGE...WILL RESULT OVER CENTRAL NC. INITIALLY CLEAR SKIES WED WILL BECOME PARTLY CLOUDY...TO PERHAPS MOSTLY SO IN THE COASTAL PLAIN...BY THU AFTERNOON...AS MOISTURE FLAT STRATOCUMULUS IS ADVECTED INLAND BENEATH THE CAP. PROJECTED LOW LEVEL THICKNESS VALUES IN THE 1300-1310 METER RANGE AT 12Z THU AND CLEAR SKIES WOULD SUPPORT SUB-FREEZING TEMPERATURES THU MORNING...BUT CONFIDENCE IS LOW REGARDING THE DEGREE OF CALM GIVEN A PROJECTED 4-6 MB RISE IN MSL PRESSURE WITH THE STRENGTHENING HIGH WED NIGHT. WILL ADJUST LOWS TO REFLECT MOSTLY LOWER TO MIDDLE 30S...COOLEST WEST...BUT THESE MAY NEED FURTHER DOWNWARD ADJUSTMENT (OR AT LEAST OPEN THE RANGE) TO INCLUDE SOME UPPER 20S (AROUND RECORD LOWS) IF IT INDEED APPEARS ANY PERIOD OF APPRECIABLE CALM WILL BE ATTAINED. SIMILARLY COOL IN THE MIDDLE 50S WED...WHICH MAY THREATEN THE RECORD LOW MAX OF 56 DEGREES AT KFAY FOR THE DATE. SEE CLIMATE SECTION BELOW. SLOW MODERATION TO AROUND 60 AND 40 DEGREES FOR HIGHS AND LOWS...RESPECTIVELY...THU AND THU NIGHT. -MWS && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... THOUGH MODEL SOLUTION SPREAD REMAINS ABOVE AVERAGE DURING THE LONG TERM...THE EMERGING SIGNAL FROM THE MAJORITY OF BOTH THE ENSEMBLE AND SOLUTIONS OS FOR A DOMINANT NORTHERN STREAM ACROSS THE NORTHERN THIRD OF THE US...ONE THAT WILL INCLUDE AT LEAST ONE PRIMARY SHORTWAVE TROUGH AND ACCOMPANYING SURFACE CYCLONE FORECAST TO CROSS THE UPPER MIDWEST AND LOWER GREAT LAKES FRI-SAT - A STORM TRACK THAT WOULD RESULT IN A MOSTLY DRY COLD FRONTAL PASSAGE SAT-SAT NIGHT AS DEPICTED BY AT LEAST THE LAST SEVERAL RUNS OF THE GFS. ON THE OTHER HAND...THE LAST COUPLE OF RUNS OF THE OPERATIONAL ECMWF...WHICH HAVE MINIMAL SUPPORT FROM THE EC ENSEMBLE MEAN...SUGGEST MORE IN THE WAY OF SOUTHERN STREAM TROUGHING/INTERACTION THAT WOULD RESULT IN SOME DEGREE OF COASTAL CYCLOGENESIS AND A WETTER PATTERN FOR AT LEAST THE EASTERN HALF OF NC DURING THE SAME TIME FRAME. IN EITHER SCENARIO...THE BEST CHANCES OF RAIN WOULD BE LATE FRI NIGHT-SAT EVENING...SO MENTIONABLE POP WILL BE CONFINED TO THAT TIME UNTIL A CLEARER PICTURE EMERGES. && .AVIATION /12Z MONDAY THROUGH SATURDAY/... AS OF 600 AM MONDAY... 24-HR TAF PERIOD: LOW-LEVEL MOISTENING /WARM ADVECTION/ IS EXPECTED TO RESULT IN THE RAPID DEVELOPMENT OF MVFR OR IFR CEILINGS BY 12-15Z ACROSS MUCH OF CENTRAL NC. SHALLOW CONVECTION (SHRA) WITH TOPS AROUND 10 KFT WILL BE POSSIBLE THROUGH EARLY AFTERNOON IN ASSOC/W AN ONSHORE FLOW IN THE LOWER-LEVELS...WITH ISOLD TO SCT SHOWERS AND THUNDERSTORMS POSSIBLE BY LATE THIS AFTERNOON AND EVENING IN ADVANCE OF A COLD FRONT PROGRESSING EAST INTO THE TN VALLEY. THERE SHOULD BE SOME MARGINAL IMPROVEMENT TO CEILINGS IN ASSOC/W DIURNAL HEATING... HOWEVER...DUE TO CONTINUED LOW-LEVEL MOISTENING CEILINGS MAY REMAIN IN THE MVFR CATEGORY...AT OR BELOW 2000 FT AGL. EXPECT CEILINGS TO DETERIORATE TO IFR/LIFR TONIGHT ALONG WITH AN INCREASING LIKELIHOOD OF SHOWER ACTIVITY IN ADVANCE OF THE APPROACHING COLD FRONT. SOUTHERLY WINDS AT 7-12 KT EARLY THIS MORNING WILL INCREASE TO 10-15 KT WITH GUSTS UP TO 22-25 KT DURING THE DAY...LIKELY REMAINING BREEZY AND GUSTING UP TO 20 KT OVERNIGHT AS THE MSLP GRADIENT TIGHTENS FROM THE WEST. LOOKING AHEAD: ADVERSE AVIATION CONDITIONS ASSOCIATED WITH WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED ON TUESDAY AS THE AFOREMENTIONED COLD FRONT PROGRESSES EAST ACROSS THE CAROLINAS. ISOLD SEVERE THUNDERSTORMS WILL BE POSSIBLE...ESPECIALLY AT THE RDU/FAY/RWI TERMINALS. SOUTHERLY OR SSW WINDS AT 15 KT WITH GUSTS UP TO 25 KT CAN BE EXPECTED IN ADVANCE OF THE FRONT THROUGH 18Z TUE...BECOMING NW/NNW AT 15 KT WITH GUSTS UP TO 25 KT BETWEEN ROUGHLY 18-21Z TUE AFTERNOON (INT/GSO) TO 00-03Z WED (FAY/RWI). IFR/LIFR CEILINGS MAY LINGER FOR A WHILE IN THE WAKE OF THE FRONTAL PASSAGE...EVENTUALLY CLEARING FROM WEST-EAST AND BECOMING VFR AFTER MIDNIGHT WED MORNING. VFR CONDITIONS WILL PREVAIL IN THE WAKE OF THE FRONT WED-FRI. -VINCENT && .CLIMATE... THE FOLLOWING ARE THE RECORD LOW TEMPERATURES FOR WED AND THU MORNING... AND THE RECORD LOW MAXIMUM TEMPERATURES FOR THU: WED 04/16 THU 04/17 LOW/YEAR LOW MAX/YEAR LOW/YEAR FAY: 28/1943 56/1950 31/1953 GSO: 25/1943 48/1929 29/1953 RDU: 28/1950 46/1890 29/1962 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/SR/VINCENT SHORT TERM...VINCENT LONG TERM...MWS AVIATION...VINCENT CLIMATE...MWS  FXUS62 KRAH 081831 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 230 PM EDT TUE JUL 8 2014 .SYNOPSIS...BROAD HIGH PRESSURE WEAKENS AS A COLD FRONT MOVES TOWARD THE REGION FROM THE GREAT LAKES. THIS COLD FRONT SHOULD MOVE INTO THE MID-ATLANTIC WEDNESDAY...WEAKENING AS IT MOVES INTO NORTH CAROLINA THURSDAY. A TROUGH OF LOW PRESSURE THEN PERSISTS OVER THE REGION AT LEAST THROUGH FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 910 AM TUESDAY... THE LATEST SURFACE ANALYSIS SHOWED BROAD HIGH PRESSURE MOSTLY OVER THE MID-ATLANTIC AND THE CAROLINAS WITH A WEAK SURFACE TROUGH AMONG THE BROAD RIDGE OVER THE CENTRAL PIEDMONT. THE SPC MESOANALYSIS SHOWED A NOTICEABLE MINIMUM OF PRECIPITABLE WATER VALUES OVER THE WESTERN PART OF THE STATE...SIMILAR TO WHAT WAS FORECAST BY THE MONDAY GUIDANCE. THE RAP FORECASTS THIS MINIMUM TO MOVE ACROSS CENTRAL NORTH CAROLINA DURING THE DAY...AND FOR THE MOST PART RAP SOUNDINGS ARE SIMILAR TO SOUNDINGS FORECAST BY THE GFS MONDAY... QUITE STABLE TO DEEP CONVECTION DURING THE DAY. TWO CAVEATS TO THIS ARE CURRENTLY...AND VERY LATE TODAY. CURRENTLY...PRECIPITABLE WATER VALUES ARE AT OR ABOVE 1.5 INCHES OVER A LARGE PART OF CENTRAL NORTH CAROLINA...AND RAP SOUNDINGS SHOW THE PRESENCE OF MID-LEVEL INSTABILITY THAT WANES BY 18Z AS THE LOWER MOISTURE VALUES MOVE EAST. THE LATEST VISIBLE IMAGERY SHOWED A NARROW BAND OF MID-LEVEL CLOUDS THAT DEVELOPED FROM NEAR ROXBORO TO WADESBORO...AND THE HRRR WRF ACTUALLY FORECASTS A SHOWER OR TWO DEVELOPING FROM THIS. WATER VAPOR IMAGERY WOULD SUGGEST ENOUGH SUBSIDENCE TO PRECLUDE A SHOWER... BUT THE DEVELOPMENT OF THE CLOUDS PLUS THE PRESENCE OF WEAK INSTABILITY MAKES IT WORTHY OF NOTE HERE. LATE TODAY...THE RAP FORECASTS LIFT MOVING INTO THE FAR NORTHWEST PIEDMONT TOWARD KINT BY 23Z. RAP SOUNDINGS ARE STILL FAIRLY STABLE AT THAT POINT...AND QPF ON THE RAP IS NIL THROUGH 00Z WEDNESDAY. PRECIPITABLE WATER VALUES INCREASE QUICKLY ON THE RAP...TO NEAR 1.5 INCHES JUST AFTER 00Z WEDNESDAY...AS K INDICES RISE TO NEAR 40. LIKE THE GFS FORECAST MONDAY...MODEST MID-LEVEL COOLING COUPLED WITH MOISTURE ADVECTION MAY BE ENOUGH FOR A SHOWER OR THUNDERSTORM TO MOVE INTO THE WEST AND NORTHWEST PIEDMONT THIS EVENING. MOS GUIDANCE POPS ARE A FEW PERCENTAGE POINTS LOWER THAN THAT GUIDANCE OF MONDAY...AND WRF ARW GUIDANCE SUGGESTS LITTLE PRECIPITATION INTO THE EVENING. STILL...THE MOISTURE ADVECTION AND SLIGHT COOLING ALOFT... COUPLED WITH A WEAKENING MID-LEVEL SHORTWAVE MOVING INTO THE WESTERN PIEDMONT THIS EVENING...IS ENOUGH TO AT LEAST CONTINUE THE SMALL CHANCES WEST AS CURRENTLY FORECAST THIS EVENING...AND MAY NEED TO EXPAND SLIGHTLY FARTHER EAST. THE 00Z GFS APPEARED TO SUFFER FROM SOME MINOR CONVECTIVE FEEDBACK WHILE THE ECMWF HAS BEEN VERY CONSISTENT IN SUGGESTING THE BEST THREAT FOR OVERNIGHT CONVECTION TO OUR NW. IT SHOULD ALSO BE NOTED THAT THE CONVECTIVE ALLOWING MODELS VERIFIED WAY OVERDONE ACROSS THE OH VALLEY INTO THE MID ATLANTIC AT 06Z. HIGHS TODAY IN THE LOWER TO MID 90S. WARM OVERNIGHT WITH LOWS NEAR 70 TO THE LOWER 70S. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 310 AM TUESDAY... MID LEVEL SHEAR AXIS ASSOCIATED WITH THE NORTHERN STREAM S/W AND ITS ATTENDANT SURFACE BOUNDARY WILL DRIFT SEWD INTO CENTRAL NC WEDNESDAY AFTERNOON-WEDNESDAY NIGHT. THIS SYSTEM WILL INTERACT WITH STRONG HEATING AND AVAILABLE MOISTURE (PRECIPITABLE WATER VALUES IN THE NEIGHBORHOOD OF 1.67-1.9 INCHES) TO INITIATE AND SUSTAIN SCATTERED CONVECTION...ESPECIALLY WEDNESDAY AFTERNOON-WEDNESDAY EVENING. SOME CONVECTIVE PARAMETERS SUGGEST SOME POTENTIAL FOR ORGANIZED CONVECTION IN THE FORM OF BROKEN CONVECTIVE SEGMENTS. IF THESE SEGMENTS WERE TO DEVELOP...COULD SEE A DAMAGING WIND THREAT WITH THE STRONGER CELLS. THIS THREAT APPEARS GREATEST ACROSS THE NORTHERN PIEDMONT INTO THE NORTHERN COASTAL PLAIN (GENERALLY NORTH OF I-40) WHERE BULK SHEAR VALUES APPROACH 30 KTS. DUE TO PRESENCE OF SHEAR AXIS AND SFC BOUNDARY...EXPECT SCATTERED CONVECTION TO PERSIST WELL INTO THE NIGHT THOUGH OVERALL COVERAGE AND INTENSITY WILL DIMINISH AS NEAR SURFACE AIR MASS UNDERGOES NOCTURNAL STABILIZATION. HIGH TEMPS WEDNESDAY DEPENDENT UPON AMOUNT OF INSOLATION AND CONVECTIVE COVERAGE. IF SUN LIMITED DUE TO EXTENSIVE CLOUD COVERAGE OR IF THE GFS IS CORRECT AND SCATTERED CONVECTION IS OCCURRING AT THE THE START OF THE DAY...THEN MAX TEMPS ACROSS THE NORTH COULD END UP BEING 5-6 DEGREES COOLER THAN FORECAST. DUE TO ANTICIPATED TIMING...BELIEVE THAT THE SOUTHERN HALF OF THE FORECAST AREA STANDS A GOOD SHOT OF SEEING TEMPS RETURNING TO THE MID 90S. MIN TEMPS WEDNESDAY NIGHT IN THE UPPER 60S TO AROUND 70 NORTH AND LOWER 70S SOUTH. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 230 PM TUESDAY... FOR THU THROUGH FRI NIGHT: THU STILL APPEARS TO BE THE BUSIEST WEATHER DAY IN TERMS OF STORM COVERAGE. A SURFACE TROUGH WILL HOLD OVER CENTRAL NC THU... WITH ELEVATED LOW LEVEL MOISTURE TRANSPORT MAINLY EAST/SOUTH OF THE TRIAD. ALOFT... BROAD TROUGHING SETTING UP JUST TO OUR WEST WILL DRAW IN NRN STREAM ENERGY AS WELL AS PULL IN PERTURBATIONS FROM AN UPPER LEVEL WEAKNESS OVER THE WRN GULF OF MEXICO. WHILE THE TROUGH ITSELF WILL BE SOMEWHAT WEAK AT THIS LATITUDE WITH MINIMAL HEIGHT FALLS (10 M AT MOST ON THU) AND MLLR VALUES UNDER 6.5 C/KM... THE ADDED DYNAMIC FORCING FOR ASCENT SHOULD SUPPORT AT LEAST SCATTERED CONVECTION (MAXIMIZING IN -- BUT NOT RESTRICTED TO -- THE AFTERNOON/EVENING) DESPITE MARGINAL VALUES OF INSTABILITY DUE TO LAYERS OF A MOIST ADIABATIC PROFILE (NAM MLCAPE TOPPING OUT AT 500-1000 J/KG WITH GFS MUCAPE OF 1000-1500 J/KG IN THE EAST THU). FORECAST DEEP LAYER SHEAR VALUES ARE MORE FAVORABLE THAN YESTERDAY'S MODEL RUNS... NOW AROUND 25-35 KTS OVER NRN/WRN NC... INDICATING THE POTENTIAL FOR MORE ORGANIZED CONVECTION... ALTHOUGH THIS BETTER SHEAR WILL NOT QUITE BE SPATIALLY ALIGNED IN AN IDEAL MANNER WITH THE GREATER INSTABILITY. NEVERTHELESS... PW VALUES WILL REMAIN ABOVE NORMAL (1.7-2.0 IN.)... AND THIS MOISTURE COMBINED WITH LOW MBE TRANSLATIONAL SPEEDS AND A DECENT WARM CLOUD DEPTH NEAR 3.5 KM SUGGESTS THAT SOME SLOW-MOVING CELLS WITH EFFICIENT RAIN PROCESSES MAY GENERATE LOCALLY HEAVY RAINFALL. WILL BUMP UP POPS TO LIKELY... HIGHER EAST THAN WEST... ON THU EXTENDING INTO EARLY THU NIGHT... UNTIL THE MID LEVELS BEGIN TO DRY OUT A BIT. THE MID LEVEL TROUGH AXIS SHIFTS EAST OF THE SRN APPALACHIANS FRI... KEEPING ERN NC IN THE CROSSHAIRS OF SUFFICIENTLY DEEP MOISTURE AND MARGINAL SHEAR AND INSTABILITY... ENOUGH TO SUPPORT PRIMARILY AFTERNOON AND EVENING SHOWERS AND STORMS... WITH THE BEST CHANCES EAST OF I-95... ALONG/EAST OF WHERE THE SURFACE TROUGH SETTLES. EXPECT LOWER COVERAGE OVER THE REST OF CENTRAL NC WITH PW SLIPPING TO NEAR OR JUST BELOW NORMAL AND LOWER DEEP LAYER SHEAR (15-20 KTS)... ALTHOUGH GFS MUCAPE PEAKS ONCE AGAIN AT 1000-1500 J/KG OVER CENTRAL NC... SO CAN'T RULE OUT SCATTERED STORMS. WILL KEEP POPS RANGING FROM 25% NW TO 40-50% SE FRI. AN APPROACHING SHORTWAVE TROUGH... POTENT BUT SLOWLY WEAKENING... WILL DROP ESE THROUGH THE LOWER GREAT LAKES/OH VALLEY LATE FRI NIGHT... LIKELY LEADING TO CONTINUED PARTLY TO MOSTLY CLOUDY SKIES DOWNSTREAM OVER NC OVERNIGHT. THICKNESSES ARE PROJECTED TO BE NEAR NORMAL THU... WHICH WITH CONSIDERATION OF GOOD CONVECTIVE CLOUD COVERAGE WOULD SUPPORT HIGHS OF 86-92. THU NIGHT LOWS NOT FAR FROM NORMAL... 67-72. SLIGHTLY LESS WARMTH ON FRI WITH BELOW-NORMAL THICKNESSES POINTING TO HIGHS OF 86-90. FOR SAT-SUN: THE SURFACE TROUGH OVER ERN NC IS LIKELY TO DISSIPATE SAT AS IT IS OVERTAKEN BY THE ATLANTIC RIDGE BULGING WESTWARD... WITH FORMATION OF A NEW WEAK LEE TROUGH OVER THE PIEDMONT AND SOME ATTENDANT MINOR RECOVERY OF PW. THE AFOREMENTIONED WEAKENING MID LEVEL WAVE WILL CROSS THE MIDATLANTIC REGION SAT... ALTHOUGH MODEL DISPARITY EMERGES AS THE ECMWF IS SLOWER/STRONGER THAN THE GFS AND THEREFORE GENERATES MORE CONVECTION OVER CENTRAL/ERN NC. WILL RETAIN CHANCE POPS SAT... HIGHER EAST THAN WEST... GENERALLY FOLLOWING THE TYPICAL DIURNAL TREND. THE GFS DEPICTS FURTHER RECOVERY OF PW VALUES SUN WITH ANOTHER MINOR WAVE CROSSING THE REGION WITHIN VERY WEAK CYCLONIC FLOW AND A RETENTION OF THE PIEDMONT SURFACE TROUGH... AND WE SHOULD SEE YET ANOTHER ROUND OF MAINLY SCATTERED DIURNALLY-DRIVEN STORMS IN THE MID AFTERNOON INTO EARLY EVENING... WITH COVERAGE AND INTENSITY LIMITED BY THE WEAK DEEP LAYER SHEAR. FOR MON-TUE: THE GFE HAS COME INTO AGREEMENT WITH THE ECMWF'S SOLUTION (CONSISTENT OVER THE LAST FEW RUNS) REGARDING THE DEEPENING MID LEVEL VORTEX WHICH DRIFTS ACROSS THE GREAT LAKES/SE ONTARIO EARLY NEXT WEEK. THE PIEDMONT SURFACE TROUGH WILL SHARPEN AND PUSH A BIT TO THE SOUTHEAST IN RESPONSE TO THE APPROACHING SYNOPTIC COLD FRONT... EXPECTED TO PROGRESS SOUTHEAST TOWARD NW NC BY LATE TUE. PW REMAINS ABOVE NORMAL AREAWIDE MON... THEN THE HIGHER VALUES SHIFT TO OUR EAST TUE WITH THE SHIFTING TROUGH AND STRENGTHENING LOW AND MID LEVEL FLOW FROM THE WSW. WILL RETAIN CLIMATOLOGICALLY TYPICAL POPS MON (SLIGHTLY LOWER IN THE TRIAD AND HIGHER TO THE SOUTH/EAST... FOCUSED ON THE AFTERNOON INTO MID EVENING)... THEN TREND POPS BACK DOWN A TAD IN THE WEST TUE. THICKNESSES REBOUND BACK CLOSER TO NORMAL SO WILL NOT DEPART MUCH FROM SEASONAL NORMALS MON/TUE (WITH NORMAL HIGH/LOW OF 90/70 AT RDU AND 89/69 AT GSO). -GIH && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 155 PM TUESDAY... VFR CONDITIONS ARE EXPECTED THROUGHOUT MUCH OF THE 18Z VALID TAF PERIOD. AS MOISTURE INCREASES AGAIN OVER THE REGION FROM THE WEST...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS SHOULD OCCUR PARTICULARLY TOWARD THE TRIAD VERY LATE THIS AFTERNOON INTO THE EVENING. WITH UNCERTAINTY IN THE LOCATION OF ANY THUNDER ONLY INCLUDED A TEMPO FOR SHOWERS IN THE TAFS FOR KINT AND KGSO FROM ABOUT 23Z TO 04Z. ISOLATED SHOWERS OR SPRINKLES ARE POSSIBLE OVERNIGHT THEN CHANCES FOR SHOWERS INCREASE DURING WEDNESDAY WITH AT LEAST TEMPO CONDITIONS ANTICIPATED AROUND THE TRIAD DURING THE MORNING. SREF MODEL PROBABILITY OF IFR CONDITIONS ARE LOW BUT PROBABILITIES OF MVFR CONDITIONS ESPECIALLY OVER THE NORTHWEST PIEDMONT INCREASE AFTER 12Z WEDNESDAY AND HAVE INCLUDED SUCH CEILINGS IN THE TEMPO CONDITIONS AT KINT AND KGSO WEDNESDAY MORNING. GUSTY SOUTHWEST WINDS SHOULD DIMINISH BUT REMAIN NOTICEABLE OUT OF THE SOUTH TO SOUTHWEST OVERNIGHT...WITH A FEW GUSTS DEVELOPING MAINLY TOWARD KFAY WEDNESDAY MORNING WHERE HEATING TO START THE DAY SHOULD BE A LITTLE BETTER RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. BEYOND THE 18Z VALID TAF PERIOD...AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS...AND THEIR ASSOCIATED SUB-VFR CONDITIONS...CAN BE EXPECTED OVER CENTRAL NORTH CAROLINA AT LEAST INTO THE END OF THE WORK WEEK. A COLD FRONT WEAKENS AS IT APPROACHES THE STATE THURSDAY...BUT A SURFACE TROUGH THEN LINGERS AT LEAST THROUGH FRIDAY AND LIKELY INTO AT LEAST PART OF THE WEEKEND. COVERAGE OF PRECIPITATION OVER CENTRAL NORTH CAROLINA SHOULD BE GREATER THURSDAY AND FRIDAY AS COMPARED TO THE UPCOMING WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...WSS/DJF SHORT TERM...WSS LONG TERM...HARTFIELD AVIATION...DJF  FXUS62 KRAH 090527 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 125 AM EDT WED JUL 9 2014 .SYNOPSIS...A SURFACE TROUGH WILL PERSIST OVER CENTRAL NORTH CAROLINA TODAY. A WEAKENING COLD FRONT WILL MOVE INTO OUR REGION THURSDAY...THEN DRIFT TOWARD THE COAST FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM TUESDAY... WEAK CONVECTION AIDED BY A SMALL MCV MOVING SOUTH OF MARTINSVILLE IS MOVING THROUGH THE TRIAD AND HAS MUSTERED UP A COUPLE OF 40 MPH GUSTS BUT NOT MUCH MORE. THIS SHOULD EVENTUALLY DIE OUT AS THE ENVIRONMENT BECOMES LESS FAVORABLE TO THE EAST BUT SOME LIGHT RAIN COULD MAKE IT AS FAR EAST AS THE TRIANGLE BUT THAT IS ABOUT IT. WINDS WILL STAY UP A LITTLE OVERNIGHT AT 5-10 KTS OUT OF THE SOUTHWEST. RELATIVE HUMIDITY CROSS SECTIONS AND ATMOSPHERIC SOUNDINGS ARE VERY DRY AT LOW LEVELS AND NOT MUCH FOG OR LOW STRATUS IS EXPECTED OVERNIGHT TONIGHT. IT WILL BE A WARM NIGHT AS TEMPERATURES ARE NOT EXPECTED TO GET MUCH LOWER THAN THE LOWER 70S. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 255 PM TUESDAY... BOTH THE NAM AND THE GFS FORECAST A MODEST BUT WEAKENING MID-LEVEL SHORTWAVE MOVING THROUGH CENTRAL NORTH CAROLINA WEDNESDAY...FOLLOWED BY ANOTHER MID-LEVEL WAVE WEDNESDAY NIGHT. ADVECTION OF K INDICES CONTINUES OVERNIGHT...WITH VALUES AT OR ABOVE 30 ACROSS CENTRAL NORTH CAROLINA FOR THE DAY WEDNESDAY. THE SOUTHWEST FLOW ALOFT THAT OCCURS OVER CENTRAL NORTH CAROLINA AS THE MID-LEVEL TROUGH SHARPENS TO OUR WEST SHOULD KEEP MOISTURE IN PLACE THROUGH AND BEYOND THIS PERIOD...WITH PERIODS OF LIFT IN ASSOCIATION WITH MID-LEVEL FORCING...A SURFACE TROUGH...AND THE APPROACHING FRONT FROM THE NORTHWEST FOR ISOLATED-TO-SCATTERED SHOWERS AND THUNDERSTORMS. NAM AND GFS BUFR SOUNDINGS ARE SOMEWHAT MOIST IN CENTRAL NORTH CAROLINA WEDNESDAY INTO WEDNESDAY NIGHT...MOST SO TOWARD THE TRIAD AND LEAST SO TOWARD KFAY. CHANCES FOR PRECIPITATION WEDNESDAY WILL BE GRADUATED AS SUCH...HIGHEST IN THE NORTHWEST PIEDMONT AND TOWARD THE VIRGINIA BORDER...LEAST IN THE SOUTHERN COASTAL PLAIN. BY WEDNESDAY NIGHT...WITH FORECAST LIFT AND INSTABILITY SHIFTING EAST...SIMILAR CHANCES FOR SHOWERS AND THUNDERSTORMS WILL EXIST ACROSS CENTRAL NORTH CAROLINA...HIGHEST NORTHEAST CLOSER TO THE SURFACE BOUNDARY. 1000-500MB LAPSE RATES ARE NOT VERY STRONG NORTH AND NORTHWEST OF THE TRIANGLE...ONLY FORECAST BY THE GFS TO JUST UNDER 6C/KM. FARTHER SOUTH...WHERE THERE IS POTENTIAL FOR BETTER HEATING...THOSE LAPSE RATES ARE NEAR 7C/KM. IT MAY BE OVER THE NORTHEAST PIEDMONT AND THE NORTHERN COASTAL PLAIN...WHERE THE BEST COMBINATION OF 0-3KM SHEAR...INSTABILITY...MOISTURE...AND LIFT RESIDE WEDNESDAY AFTERNOON...WHERE THE STRONGER STORMS MAY OCCUR. THE ARW WRF SUGGESTS THIS...BUT NOT CONFIDENT ENOUGH AT THIS TIME TO BE THAT SPECIFIC IN THE HAZARDOUS WEATHER OUTLOOK. SPC DAY TWO OUTLOOK SHOWS A FIVE PERCENT OUTLOOK FOR ALL OF CENTRAL NORTH CAROLINA FOR WEDNESDAY...AND WILL RETAIN THE CURRENT WORDING IN THE HWO. SREF GUIDANCE AND BUFR SOUNDINGS SUGGEST GOOD POTENTIAL FOR DECENT CLOUD COVER FOR MUCH OF WEDNESDAY IN THE NORTHWEST PIEDMONT...AND HIGH TEMPERATURES ON WEDNESDAY WILL HAVE A GRADIENT FROM THE MID TO UPPER 80S OVER THE IMMEDIATE TRIAD TO AROUND 95 TOWARD KFAY. SURFACE WINDS SHOULD GUST TO AROUND 20KT AT TIMES TOWARD KFAY WEDNESDAY IN BETTER HEATING...WITH LESSER GUSTS OUTSIDE OF ANY DEEP CONVECTION ELSEWHERE. OVERNIGHT LOWS WEDNESDAY NIGHT 68 TO 74. && .LONG TERM /THURSDAY THROUGH TUESDAY/... AS OF 230 PM TUESDAY... FOR THU THROUGH FRI NIGHT: THU STILL APPEARS TO BE THE BUSIEST WEATHER DAY IN TERMS OF STORM COVERAGE. A SURFACE TROUGH WILL HOLD OVER CENTRAL NC THU... WITH ELEVATED LOW LEVEL MOISTURE TRANSPORT MAINLY EAST/SOUTH OF THE TRIAD. ALOFT... BROAD TROUGHING SETTING UP JUST TO OUR WEST WILL DRAW IN NRN STREAM ENERGY AS WELL AS PULL IN PERTURBATIONS FROM AN UPPER LEVEL WEAKNESS OVER THE WRN GULF OF MEXICO. WHILE THE TROUGH ITSELF WILL BE SOMEWHAT WEAK AT THIS LATITUDE WITH MINIMAL HEIGHT FALLS (10 M AT MOST ON THU) AND MLLR VALUES UNDER 6.5 C/KM... THE ADDED DYNAMIC FORCING FOR ASCENT SHOULD SUPPORT AT LEAST SCATTERED CONVECTION (MAXIMIZING IN -- BUT NOT RESTRICTED TO -- THE AFTERNOON/EVENING) DESPITE MARGINAL VALUES OF INSTABILITY DUE TO LAYERS OF A MOIST ADIABATIC PROFILE (NAM MLCAPE TOPPING OUT AT 500-1000 J/KG WITH GFS MUCAPE OF 1000-1500 J/KG IN THE EAST THU). FORECAST DEEP LAYER SHEAR VALUES ARE MORE FAVORABLE THAN YESTERDAY'S MODEL RUNS... NOW AROUND 25-35 KTS OVER NRN/WRN NC... INDICATING THE POTENTIAL FOR MORE ORGANIZED CONVECTION... ALTHOUGH THIS BETTER SHEAR WILL NOT QUITE BE SPATIALLY ALIGNED IN AN IDEAL MANNER WITH THE GREATER INSTABILITY. NEVERTHELESS... PW VALUES WILL REMAIN ABOVE NORMAL (1.7-2.0 IN.)... AND THIS MOISTURE COMBINED WITH WEAK STEERING FLOW AND A DECENT WARM CLOUD DEPTH NEAR 3.5 KM SUGGESTS THAT SLOW-MOVING CELLS WITH EFFICIENT RAIN PROCESSES MAY GENERATE LOCALLY HEAVY RAINFALL. WILL BUMP UP POPS TO LIKELY... HIGHER EAST THAN WEST... ON THU EXTENDING INTO EARLY THU NIGHT... UNTIL THE MID LEVELS BEGIN TO DRY OUT A BIT. THE MID LEVEL TROUGH AXIS SHIFTS EAST OF THE SRN APPALACHIANS FRI... KEEPING ERN NC IN THE CROSSHAIRS OF SUFFICIENTLY DEEP MOISTURE AND MARGINAL SHEAR AND INSTABILITY... ENOUGH TO SUPPORT PRIMARILY AFTERNOON AND EVENING SHOWERS AND STORMS... WITH THE BEST CHANCES EAST OF I-95... ALONG/EAST OF WHERE THE SURFACE TROUGH SETTLES. EXPECT LOWER COVERAGE OVER THE REST OF CENTRAL NC WITH PW SLIPPING TO NEAR OR JUST BELOW NORMAL AND LOWER DEEP LAYER SHEAR (15-20 KTS)... ALTHOUGH GFS MUCAPE PEAKS ONCE AGAIN AT 1000-1500 J/KG OVER CENTRAL NC... SO CAN'T RULE OUT SCATTERED STORMS. WILL KEEP POPS RANGING FROM 25% NW TO 40-50% SE FRI. AN APPROACHING SHORTWAVE TROUGH... POTENT BUT SLOWLY WEAKENING... WILL DROP ESE THROUGH THE LOWER GREAT LAKES/OH VALLEY LATE FRI NIGHT... LIKELY LEADING TO CONTINUED PARTLY TO MOSTLY CLOUDY SKIES DOWNSTREAM OVER NC OVERNIGHT. THICKNESSES ARE PROJECTED TO BE NEAR NORMAL THU... WHICH WITH CONSIDERATION OF GOOD CONVECTIVE CLOUD COVERAGE WOULD SUPPORT HIGHS OF 86-92. THU NIGHT LOWS NOT FAR FROM NORMAL... 67-72. SLIGHTLY LESS WARMTH ON FRI WITH BELOW-NORMAL THICKNESSES POINTING TO HIGHS OF 86-90. FOR SAT-SUN: THE SURFACE TROUGH OVER ERN NC IS LIKELY TO DISSIPATE SAT AS IT IS OVERTAKEN BY THE ATLANTIC RIDGE BULGING WESTWARD... WITH FORMATION OF A NEW WEAK LEE TROUGH OVER THE PIEDMONT AND SOME ATTENDANT MINOR RECOVERY OF PW. THE AFOREMENTIONED WEAKENING MID LEVEL WAVE WILL CROSS THE MIDATLANTIC REGION SAT... ALTHOUGH MODEL DISPARITY EMERGES AS THE ECMWF IS SLOWER/STRONGER THAN THE GFS AND THEREFORE GENERATES MORE CONVECTION OVER CENTRAL/ERN NC. WILL RETAIN CHANCE POPS SAT... HIGHER EAST THAN WEST... GENERALLY FOLLOWING THE TYPICAL DIURNAL TREND. THE GFS DEPICTS FURTHER RECOVERY OF PW VALUES SUN WITH ANOTHER MINOR WAVE CROSSING THE REGION WITHIN VERY WEAK CYCLONIC FLOW AND A RETENTION OF THE PIEDMONT SURFACE TROUGH... AND WE SHOULD SEE YET ANOTHER ROUND OF MAINLY SCATTERED DIURNALLY-DRIVEN STORMS IN THE MID AFTERNOON INTO EARLY EVENING... WITH COVERAGE AND INTENSITY LIMITED BY THE WEAK DEEP LAYER SHEAR. FOR MON-TUE: THE GFE HAS COME INTO AGREEMENT WITH THE ECMWF'S SOLUTION (CONSISTENT OVER THE LAST FEW RUNS) REGARDING THE DEEPENING MID LEVEL VORTEX WHICH DRIFTS ACROSS THE GREAT LAKES/SE ONTARIO EARLY NEXT WEEK. THE PIEDMONT SURFACE TROUGH WILL SHARPEN AND PUSH A BIT TO THE SOUTHEAST IN RESPONSE TO THE APPROACHING SYNOPTIC COLD FRONT... EXPECTED TO PROGRESS SOUTHEAST TOWARD NW NC BY LATE TUE. PW REMAINS ABOVE NORMAL AREAWIDE MON... THEN THE HIGHER VALUES SHIFT TO OUR EAST TUE WITH THE SHIFTING TROUGH AND STRENGTHENING LOW AND MID LEVEL FLOW FROM THE WSW. WILL RETAIN CLIMATOLOGICALLY TYPICAL POPS MON (SLIGHTLY LOWER IN THE TRIAD AND HIGHER TO THE SOUTH/EAST... FOCUSED ON THE AFTERNOON INTO MID EVENING)... THEN TREND POPS BACK DOWN A TAD IN THE WEST TUE. THICKNESSES REBOUND BACK CLOSER TO NORMAL SO WILL NOT DEPART MUCH FROM SEASONAL NORMALS MON/TUE (WITH NORMAL HIGH/LOW OF 90/70 AT RDU AND 89/69 AT GSO). -GIH && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 125 AM WEDNESDAY... VFR CONDITIONS WILL GENERALLY PERSIST THROUGH 18Z. AFTER 18Z...A SERIES OF UPPER LEVEL DISTURBANCES COUPLED WITH A SLOWLY WEAKENING SURFACE COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED CONVECTION ACROSS CENTRAL NC. BETWEEN 20Z AND 01Z...THE THREAT FOR SCATTERED CONVECTION AND ASSOCIATED MVFR/IFR CEILINGS AND VISIBILITIES WILL BE GREATEST ON VICINITY OF THE TRIAD TERMINALS AS WELL AS KRDU. IN VICINITY OF THE STRONGER CONVECTION...WIND GUSTS UP TO 40KTS PROBABLE. THE ATMOSPHERE WILL REMAIN UNSETTLED TONIGHT THROUGH THURSDAY NIGHT AS THE SURFACE COLD FRONT GRADUALLY DRIFTS SEWD ACROSS THE REGION AND THE SERIES OF DISTURBANCES LIFT ACROSS THE REGION. WHILE CONVECTIVE COVERAGE AND INTENSITY WILL DWINDLE OVERNIGHT...ISOLATED TO SCATTERED SHOWERS AND T-STORMS WILL STILL OCCUR WELL PAST MIDNIGHT. THE CONVECTIVE ACTIVITY IS EXPECTED TO REACH ITS PEAK COVERAGE THURSDAY AFTERNOON AND EVENING WHEN SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE NUMEROUS. BETTER AVIATION CONDITIONS ANTICIPATED FRIDAY THROUGH SATURDAY AS A SLIGHTLY DRIER MORE STABLE AIR MASS ENCOMPASSES MOST OF THE REGION. SCATTERED AFTERNOON-EARLY EVENING CONVECTION WILL STILL BE PROBABLE IN VICINITY OF KFAY AND KRWI WHERE AVAILABLE MOISTURE AND LOW LEVEL INSTABILITY WILL BE BEST. BY SUNDAY...REMNANTS OF DECAYING THUNDERSTORM COMPLEXES ORIGINATING IN THE MIDWEST MAY BEGIN TO AFFECT CENTRAL NC...LEADING TO A BETTER CHANCE FOR SCATTERED CONVECTION AND ASSOCIATED MVFR CONDITIONS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...ELLIS SHORT TERM...DJF LONG TERM...HARTFIELD AVIATION...WSS  FXUS62 KRAH 291947 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 345 PM EDT SUN MAR 29 2015 .SYNOPSIS...HIGH PRESSURE OVERHEAD WILL MOVE OFFSHORE TONIGHT AHEAD OF A COLD FRONT. THIS COLD FRONT WILL MOVE THROUGH THE REGION MONDAY. ANOTHER COLD FRONT SHOULD MOVE THROUGH THE REGION OVERNIGHT TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 230 PM SUNDAY... CLOUDS WILL BEGIN TO INCREASE LATER THIS EVENING AHEAD OF AN APPROACHING FRONT. EVEN WITH EXTREMELY DRY AIR CURRENTLY IN PLACE (SINGLE DIGIT DEWPOINTS)...MOISTURE AND LIFT WILL INCREASE THROUGH MONDAY MORNING. LIFT WILL INCREASE AS THE RIGHT ENTRANCE REGION OF A UPPER LEVEL JET MOVES IN LATE TONIGHT. THIS WILL RESULT IN A BAND OF SHOWERS MOVING THROUGH THE AREA FROM WEST TO EAST...ROUGHLY BETWEEN 09-16Z. POPS WILL QUICKLY DECREASE LATE MONDAY MORNING THROUGH EARLY AFTERNOON. QPF VALUES ARE PROGGED TO BE RATHER LIGHT WITH ONLY A TENTH OF AN INCH OR SO. OVERNIGHT LOWS TONIGHT SHOULD FALL INTO THE 30S BEFORE LEVELING OUT OR EVEN RISING A COUPLE OF DEGREES AS THE SURFACE GRADIENT INCREASES. THERE COULD BE A SHORT WINDOW WHEN TEMPS FALL TO NEAR OR JUST BELOW 35 DEGREES PARTICULARLY IN THE COASTAL PLAIN. HOWEVER... WITH INCREASING WINDS AND THE DRY AIR IN PLACE...CONFIDENCE IS NOT HIGH ENOUGH FOR ANY WIDESPREAD FROST. IF WINDS DO DECOUPLE FOR A LONGER TIME FRAME...A SHORT FUSED FROST ADVISORY MAY BE NEEDED FOR THE SOUTHEAST COUNTIES. OTHERWISE...THE COLD FRONT IS NOT EXPECTED TO MOVE THROUGH UNTIL LATE MONDAY...WHICH SHOULD ALLOW TEMPS TO RISE INTO THE LOW/MID 60S. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 315 PM SUNDAY... MONDAY NIGHT AND TUESDAY... WEAK SURFACE HIGH PRESSURE WILL BUILD INTO CENTRAL NC IN THE WAKE OF THE EXITING FRONTAL SYSTEM MONDAY NIGHT INTO EARLY TUESDAY. THE APPROACH OF A DISTURBANCE IN THE NW FLOW ALOFT MAY INITIATE A PERIOD OF OROGRAPHIC CIRRUS OVER OUR REGION BY EARLY TUESDAY. THE SURFACE FRONT AND WAVE ASSOCIATED WITH THE DISTURBANCE ALOFT WILL CROSS TO OUR NORTH TUESDAY AFTERNOON AND EVENING. THIS WILL SET-UP A LEE SIDE TROUGH OVER THE WESTERN PIEDMONT BY TUESDAY AFTERNOON. THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN IN RESPONSE TO THIS LEE SIDE TROUGH AND THE APPROACHING SFC LOW. THE RESULTANT SW LOW LEVEL FLOW WILL AID TO BOOST TEMPS BACK TO NEAR NORMAL LEVELS. MIN TEMPS MONDAY NIGHT UPPER 30S TO AROUND 40. MAX TEMPS TUESDAY UPPER 60S-LOWER 70S. TUESDAY NIGHT AND WEDNESDAY...SFC COLD FRONT WILL SWEEP ACROSS CENTRAL NC PRETTY UNEVENTFUL AS ATMOSPHERE TOO DRY TO SUPPORT PRECIP GENERATION. BULK OF COLD AIR BEHIND THE FRONT WILL REMAIN MOSTLY TO OUR NORTH. 850MB THERMAL TROUGH DOES EXTEND SWD INTO THE NORTHERN COUNTIES ON WEDNESDAY WITH EFFECTS A BIT MORE PRONOUNCED OVER THE NORTHERN COASTAL PLAIN VERSUS THE WESTERN-SOUTHERN PIEDMONT. MIN TEMPS TUESDAY NIGHT MID-UPPER 40S. HIGH TEMPS WEDNESDAY LOW-MID 60S NE TO THE LOWER 70S SW. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 345 PM SUNDAY... THURSDAY...MEDIUM RANGE MODELS IN DECENT AGREEMENT...DEPICTING A WEAKENING MID LEVEL S/W IN THE SOUTHERN STREAM LIFTING ACROSS THE DEEP SOUTH INTO THE SE U.S. MEANWHILE A S/W IN THE NORTHERN STREAM WILL PROGRESS EAST ACROSS THE GREAT LAKES INTO THE NEW ENGLAND...DRAGGING A COLD FRONT TOWARD CENTRAL NC BY THURSDAY NIGHT. BULK OF SHOWERS ASSOCIATED WITH THE SOUTHERN SYSTEM WILL LIKELY OCCUR MORE TO OUR WEST-SW...WITH SHOWER GENERATION DECREASING FARTHER EAST AS SYSTEM SHEARS OUT. SW FLOW AHEAD OF THE APPROACHING COLD FRONT WILL CONTINUE TO PULL WARM AIR INTO CENTRAL NC. THE MIXTURE OF SUN/CLOUDS AND SPOTTY SHOWER COVERAGE SHOULD PERMIT TEMPS TO REBOUND INTO THE 70S AREAWIDE. IF SUN IS MORE PREVALENT THAN CLOUDS THURSDAY AFTERNOON...COULD SEE TEMPS REACH/SLIGHTLY EXCEED 80 DEGREES OVER TEH SE HALF. FRIDAY INTO SATURDAY...SFC COLD FRONT WILL DRIFT SLOWLY EAST-SE THROUGH THIS PERIOD...POSSIBLY EXITING OUR EASTERN COUNTIES BY MID DAY SATURDAY (BASED ON SLOWER GFS). APPEARS BULK OF SHOWERS FRIDAY WILL OCCUR WEST-NORTH OF CENTRAL NC...THOUGH INCREASING ACROSS THE PIEDMONT BY LATE IN THE DAY. SHOWER COVERAGE SHOULD MAXIMIZE FRIDAY NIGHT AS THE FRONT DRIFTS ACROSS THE AREA. MAX TEMPS FRIDAY DEPENDENT ON SHOWER COVERAGE AND CLOUD THICKNESS. POTENTIAL FOR TEMPS TO REACH 80 AGAIN IN THE FAR SE FRIDAY AFTERNOON IF SHOWERS AND CLOUDS ARE DELAYED. SHOULD SEE SLIGHTLY COOLER TEMPS FRIDAY IN THE FAR NORTH-NW DUE TO MORE EXTENSIVE CLOUD COVERAGE. SLIGHTLY COOLER TEMPS ANTICIPATED SATURDAY WITH SHOWER THREAT DIMINISHING NW- SE THROUGHOUT THE DAY. EASTER SUNDAY AT THIS TIME APPEARS DRY AND SEASONABLY COOL AS HIGH PRESSURE BUILDS INTO OUR REGION FROM THE NW. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 145 PM SUNDAY... VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE MAJORITY OF THE CURRENT TAF PERIOD. CURRENT LIGHT AND VARIABLE WINDS WILL BECOME MORE UNIFORMLY SOUTHWESTERLY OVER THE NEXT SEVERAL HOURS. LATE TONIGHT INTO MONDAY MORNING...A BAND OF SHOWERS AHEAD OF AN APPROACHING COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST... LIKELY BETWEEN 09-16Z. WHILE A BRIEF PERIOD OF IFR CEILINGS WILL BE POSSIBLE WITH AND JUST BEHIND THE BAND OF SHOWERS...THE PREDOMINANT CEILING TYPE SHOULD BE IN THE LOW MVFR RANGE. ANY SUB-VFR CONDITIONS SHOULD IMPROVE TO VFR A COUPLE OF HOURS BEHIND THE LINE OF SHOWERS. WESTERLY WINDS SHOULD PICK UP BEHIND THE LINE OF SHOWERS...WITH GUSTS UP TO 20-25 MPH POSSIBLE. OUTLOOK...VFR CONDITIONS SHOULD PREDOMINATE THROUGH THE MIDDLE OF WEEK...WITH A LOW PROBABILITY OF A BRIEF PERIOD OF MVFR CEILINGS WITH ANOTHER COLD FRONT DURING THE DAY WEDNESDAY. ANOTHER PERIOD OF ADVERSE AVIATION CONDITIONS WILL BE POSSIBLE LATE IN THE WEEK AS A SOUTHERN STREAM SYSTEM APPROACHES FROM THE SOUTHWEST. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...KRD/DJF NEAR TERM...KRD SHORT TERM...WSS LONG TERM...WSS AVIATION...KRD  FXUS62 KRAH 040721 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 315 AM EDT MON MAY 4 2015 .SYNOPSIS....SYNOPSIS... HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL EXTEND INTO THE REGION THROUGH MID WEEK. AN AREA OF LOW PRESSURE WILL FORM NEAR THE BAHAMAS DURING THE MIDDLE OF THE WEEK AND MOVE SLOWLY NORTH TOWARD THE SOUTHEAST COAST. && .NEAR TERM /TODAY/... AS OF 300 AM MONDAY... LATEST SURFACE ANALYSIS SHOWS HIGH PRESSURE CENTERED JUST OFF THE CAROLINA COAST WITH A LIGHT SOUTHERLY SURFACE FLOW ACROSS CENTRAL NC. WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH LOCATED OVER SOUTHWESTERN VA EARLY THIS MORNING DRIFTING SLOWLY SOUTHEAST. THE WEAK VORTEX HAS VERY LITTLE MOISTURE TO WORK WITH AT MID LEVELS ATOP A DRY AND INCREASINGLY WELL MIXED BOUNDARY LAYER TODAY. THE RESULT SHOULD BE MOSTLY SUNNY SKIES THIS MORNING THAT GIVE WAY TO PARTLY AND PERHAPS BRIEFLY OCCASIONALLY MOSTLY CLOUDY SKIES THIS AFTERNOON. THE HIGH-BASED CUMULUS FIELD WILL BE THICKEST ACROSS THE WESTERN PIEDMONT AND TRIAD. GUIDANCE INCLUDING SOME HIGH RES CONVECTION ALLOWING MODELS SUGGEST A FEW SHOWERS ACROSS THE MOUNTAINS TODAY. THE SAME GUIDANCE WAS A LITTLE TOO BULLISH ON THIS POTENTIAL FOR SUNDAY WITH VERY LITTLE IF ANY SHOWERS DEVELOPING. SO HAVE DECIDED TO HOLD ONTO THE SLIGHT CHANCE OF SHOWERS ACROSS THE FAR WESTERN ZONES NEAR THE YADKIN VALLEY AS A FEW SHOWERS MAY DRIFT EAST INTO THESE AREAS LATE IN THE DAY BEFORE DISSIPATING. HIGHS TODAY SHOULD BE A COUPLE OF DEGREES WARMER THAN ON SUNDAY GIVEN LOW LEVEL THICKNESS VALUES THAT START OFF 5-10M WARMER. WILL FORECAST HIGHS OF 79 NORTHWEST TO 83 SOUTHEAST. -BLAES && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 315 AM MONDAY... GENERALLY FAIR WEATHER IS EXPECTED THROUGH THE PERIOD AS SURFACE HIGH PRESSURE EXTENDS INTO THE AREA FROM THE ATLANTIC AND WEAK RIDGING DEVELOPS OVER THE REGION. THE MAIN FORECAST PROBLEM IS ASSOCIATED WITH THE SCATTERED DIURNAL CONVECTION THAT WILL LIKELY DEVELOP ACROSS THE MOUNTAINS AGAIN ON TUESDAY AFTERNOON. WHILE THE MIXED LAYER TUESDAY AFTERNOON IS NOT AS DEEP AS TODAY AND BOUNDARY LAYER MOISTURE INCREASES SLIGHTLY...STILL BELIEVE THE POTENTIAL FOR MOUNTAIN CONVECTION REACHING CENTRAL NC IS LIMITED. THE FLOW THROUGH THE CLOUD DEPTH IS WEAKER AND MORE NORTHERLY SUGGESTING CONVECTION MAY HAVE A HARD TIME PUSHING EAST AND IN FACT MAIN DRIFT SOUTH OR REMAIN ANCHORED TO THE TERRAIN. WITH THIS IN MIND WILL OMIT POPS FOR OUR WESTERN ZONES FOR TUESDAY AFTERNOON. EXPECT MAINLY CLEAR SKIES MONDAY NIGHT WITH PARTLY CLOUDY SKIES ON TUESDAY. MAINLY CLEAR SKIES ARE EXPECTED AGAIN TUESDAY NIGHT ALTHOUGH THE NAM AND A FEW SREF MEMBERS SUGGEST SOME SHALLOW STRATUS MAY APPROACH THE SANDHILLS AND SOUTHERN COASTAL PLAIN TOWARD DAYBREAK WEDNESDAY. LOWS ON TUESDAY MORNING WILL RANGE IN THE LOWER TO MID 50S WITH HIGHS AGAIN IN THE 79-84 RANGE. LOWS TUESDAY NIGHT WILL RANGE IN THE MID TO UPPER 50S. -BLAES && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 220 AM MONDAY... ...MID TO LATE WEEK FORECAST STILL CLOUDED BY POTENTIAL FOR COASTAL LOW DEVELOPMENT... THERE IS HIGH CONFIDENCE IN THE EXPECTED TROUGH OVER THE SOUTHWESTERN UNITED STATES THIS WEEK... WITH RIDGING OVER THE EASTERN STATES... WITH THE POTENTIAL FOR THE CUT OFF LOW DEVELOPMENT OFFSHORE OF THE SOUTH ATLANTIC COAST. THE LATEST MODEL GUIDANCE CONTINUED TO INDICATE A COUPLE OF CAMPS STILL EXIST ON THE POTENTIAL LOW PRESSURE DEVELOPMENT OFF THE SOUTHEAST COAST. THE TRENDS OF RECENT GFS RUNS AND ENSEMBLE MEANS ALONG WITH THE GEFS/ECENS/CANADIAN ALL FAVOR AT LEAST A MORE WESTWARD POSITION OF THE LOW PRESSURE... WHILE AT LEAST THE 12Z/03 ECMWF/CANADIAN GLOBAL/UKMET LIE FARTHER EAST. THE LATEST OPERATIONAL GFS ACTUALLY PULLS THE LOW PRESSURE WELL WESTWARD AND INLAND OVER SC LATE THURSDAY INTO FRIDAY. HPC CONTINUED TO FAVOR USING THE ENSEMBLES WHICH WOULD BE A COMPROMISE SOLUTION AND KEEPING THE LOW PRESSURE OFF THE SC COAST. THE HURRICANE CENTER IS MONITORING AND HAS INDICATED THAT THE SYSTEM... IF IT DEVELOPS... MAY HAVE SUBTROPICAL CHARACTERISTICS. IT APPEARS THAT THE FARTHER NORTH THE SYSTEM TRACKS... THE LESS IN THE WAY OF TROPICAL SUPPORT IT WOULD HAVE GIVEN THE LESS THAN FAVORABLE WATER TEMPERATURES OFF THE CAROLINA COAST. OBVIOUSLY... THE ULTIMATE DEVELOPMENT AND SUBSEQUENT TRACK OF THE SYSTEM WILL GO A GREAT WAY IN DETERMINING IF OUR REGION WILL GET SIGNIFICANT RAINFALL THIS PERIOD GIVEN THE UPPER RIDGING IN PLACE. FINALLY... THE EAST COAST UPPER RIDGE AND POSSIBLY THE MID/UPPER SOUTHEASTERN US CUT OFF LOW MAY FINALLY GET A BIT OF A KICKER LATE IN THE WEEKEND AS THE TROUGH OUT WEST FINALLY PULLS OUT INTO THE PLAINS AND MIDWEST INCREASING OUR SW FLOW ALOFT. FOR NOW... WE WILL MAINTAIN A MOSTLY DRY FORECAST WITH A SLIGHT CHANCE OF MAINLY AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS THURSDAY THROUGH THE WEEKEND GIVEN THE UNCERTAINTY. REGARDLESS... WITH THE UPPER RIDGE IN PLACE... TEMPERATURES WILL BE MUCH WARMER THIS WEEK. LOWS LATER IN THE WEEK SHOULD BE AT OR ABOVE 60 OR EVEN 65. HIGHS GENERALLY 80-85. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 200 AM MONDAY... MODERATE CONFIDENCE OF VFR CONDITIONS THROUGH THE 24 HOUR TAF PERIOD AS HIGH PRESSURE CENTERED TO OUR SOUTH SLOWLY SLIPS OFF THE COAST BUT EXTENDS INTO THE REGION THROUGH TUESDAY. AN UPPER LEVEL SHORT WAVE TROUGH WILL SLOWLY MOVE ACROSS CENTRAL NC TODAY AND OFF THE COAST TONIGHT. WHILE A FEW SHOWERS ARE LIKELY TO DEVELOP ACROSS MOUNTAINS TODAY AND DRIFT EAST...THE PROBABILITY OF ANY OF THESE SHOWERS REACHING THE TRIAD REMAINS VERY SMALL AND WILL BE OMITTED FROM THE TAF. THE ONLY OTHER POTENTIALLY ADVERSE WEATHER COULD BE A BRIEF PERIOD OF MVFR RADIATION FOG AT KRWI TOWARD DAYBREAK TODAY. OTHERWISE SCT CLOUDS AT 6-10KFT THIS MORNING WILL GIVE WAY TO A MORE PROMINENT CLOUD DECK OF SCT-BKN CUMULUS THIS AFTERNOON AT AROUND 6-8KFT. A LIGHT MAINLY SOUTHERLY WIND FROM 190- 220 DEGREES AT 5-10 KTS IS EXPECTED TODAY. OUTLOOK...GENERALLY FAIR WEATHER IS EXPECTED FOR LATE TONIGHT INTO TUESDAY NIGHT WITH SHOWERS DEVELOPING ACROSS THE MOUNTAINS TUESDAY AND WEDNESDAY AFTERNOONS. AN ONSHORE FLOW WILL INCREASE AND PERSIST DURING THE MID AND LATE WEEK AS LOW PRESSURE DEVELOPS NEAR THE BAHAMAS AND DRIFTS NORTH. A WEAK FRONT WILL ALSO DROP INTO THE REGION LATE WEDNESDAY INTO THURSDAY. MOISTURE IS EXPECTED TO INCREASE DURING THE WEEK ALONG WITH THE THREAT OF EARLY MORNING STRATUS/FOG. THERE IS THE POTENTIAL FOR MORE WIDESPREAD ADVERSE AVIATION CONDITIONS ASSOCIATED WITH THE COASTAL STORM SYSTEM TO ARRIVE LATE IN THE WORK WEEK. -BLAES && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...WSS SHORT TERM...22 LONG TERM...BADGETT AVIATION...BLAES  FXUS62 KRAH 010040 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 840 PM EDT SAT OCT 31 2015 .SYNOPSIS...HIGH PRESSURE MOVES OFF OF THE MID ATLANTIC COAST OVERNIGHT. A WARM FRONT MOVES NORTH INTO THE CAROLINAS SUNDAY AND SUNDAY NIGHT. A LOW PRESSURE SYSTEM WILL SLOWLY MOVE FROM THE WESTERN GULF INTO THE CAROLINAS BY MONDAY. HIGH PRESSURE BUILDS BACK IN LATER IN THE WEEK. && .NEAR TERM /THROUGH THE OVERNIGHT/... AS OF 840 PM SATURDAY... WEATHER PATTERN CHANGE UNDERWAY ACROSS CENTRAL NC AS FLOW THROUGH THE COLUMN AS BECOME WEST-SW...INDICATIVE THAT THE AREA OF HIGH PRESSURE HAS MOVED FURTHER OFFSHORE....WITH MID-HIGH LEVEL CLOUDS STREAMING INTO THE REGION. THIS CLOUD DECK WILL THICKEN INTO THE OVERNIGHT. 00Z UPPER AIR ANALYSIS DEPICTS DECENT SPEED CONVERGENCE IN THE 700-500MB LAYER. MEANWHILE THE SFC-700MB LAYER STILL RELATIVELY DRY AS PER 00Z GSO SOUNDING. AS THE MID/UPPER SPEED CONVERGENCE INCREASES...SHOULD SEE LIGHT RADAR ECHOES CROSS OUR PIEDMONT COUNTIES WITH A FEW SPRINKLES HIGHLY PROBABLE IN THE YADKIN RIVER VALLEY AND THE TRIAD REGION BY MIDNIGHT OR SHORTLY THEREAFTER. CLOSER TO DAYBREAK SUNDAY...LOW LEVEL SLY FLOW ABOVE THE SURFACE WILL STRENGTHEN IN RESPONSE TO A S/W CROSSING THE OH VALLEY AND INTO THE CENTRAL APPALACHIANS...SHEARING OUT/WEAKENING AS IT DOES SO. THIS ENHANCEMENT OF THE SLY WILL INCREASE ISENTROPIC UPGLIDE...ESPECIALLY OVER THE PIEDMONT...LEADING TO INCREASING CHANCES FOR MEASURABLE RAIN. THE 12Z ECMWF VERIFIED RELATIVELY WELL WITH THE EASTERN EXTENT OF THE PRECIP SHIELD OVER THE DEEP SOUTH AT 18Z AND 00Z. IF THIS TREND CONTINUES...SHOULD SEE MEASURABLE RAIN PRIOR TO 12Z ALONG AND WEST OF LINE FROM ROXBORO-SILER CITY- ROCKINGHAM. THUS HAVE TWEAKED THE POP FORECAST A BIT TO ADVERTISE THE SLIGHTLY FASTER ARRIVAL OF THE MEASURABLE RAIN. TEMPS THIS EVENING WILL INITIALLY COOL...ESPECIALLY IN THE NE WHERE THE CLOUD DEPTH NOT AS THICK. AS CLOUDS THICKEN AND LOWER...TEMPS WILL STABILIZE/HOLD STEADY OVERNIGHT. MIN TEMPS GENERALLY 50-55 DEGREES. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 140 PM SATURDAY... ...HEAVY RAIN EXPECTED ACROSS PORTIONS OF CENTRAL NC SUNDAY NIGHT INTO MONDAY... SUN/SUN NIGHT: PERIODS OF LIGHT RAIN OR SPRINKLES ARE EXPECTED DURING THE DAY SUNDAY (PRIMARILY IN THE WEST/SW PIEDMONT) AS LOW- LEVEL WARM ADVECTION PERSISTS/STRENGTHENS IN THE PRESENCE OF SMALL AMPLITUDE DISTURBANCES /DPVA/ EMBEDDED IN STRENGTHENING SW FLOW ALOFT DOWNSTREAM OF THE SOUTHERN STREAM WAVE. BY SUN NIGHT...THE POTENT SOUTHERN STREAM WAVE WILL TRACK INTO THE DEEP SOUTH AND A PRONOUNCED WARM FRONT WILL LIFT NORTHWARD INTO SOUTHERN PORTIONS OF NC. GIVEN INCREASING MOISTURE AND STRENGTHENING LOWER/UPPER LEVEL FORCING...PRECIPITATION IS EXPECTED TO INCREASE IN COVERAGE/ INTENSITY ACROSS CENTRAL NC SUN NIGHT...ESPECIALLY ALONG AND NORTH OF THE WARM FRONT WHERE A HEAVY WSW-ENE OR SW-NE ORIENTED BAND MAY DROP AS MUCH AS 1.00-1.50" OF RAIN BETWEEN 00-12Z MON. AT THIS TIME...ANY CONVECTION THAT DEVELOPS IS EXPECTED TO REMAIN ELEVATED IN NATURE (THROUGH SUNRISE MON). HIGHS SUNDAY RANGING FROM THE LOWER 60S NW TO LOWER 70S SE...LOWS SUN NIGHT MID 50S NW TO LOWER 60S SOUTHEAST. -VINCENT MON/MON NIGHT: THE AFOREMENTIONED POTENT SOUTHERN STREAM WAVE WILL CONTINUE TO TRACK INTO THE MID ATLANTIC REGION...BUT WILL GRADUALLY DAMPEN AS IT TRACKS NORTH/EAST. THE ASSOCIATED SURFACE LOW IS PROGGED TO TRACK ALONG/NEAR THE WARM FRONT WHICH IS EXPECTED TO BE DRAPED ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA. AS A RESULT...WIDESPREAD...LOCALLY HEAVY...RAIN WILL CONTINUE THROUGH THE DAY ON MONDAY. HEAVIEST AMOUNT SHOULD BE NORTH OF THE WARM FRONT (ACROSS THE NORTHWESTERN TWO THIRDS OF THE FORECAST AREA)...WHERE AN ADDITIONAL INCH COULD OCCUR. BY MONDAY NIGHT...THE SURFACE LOW WILL SLIP OFFSHORE...ALONG WITH THE LOW LEVEL JET...AND PRECIP WILL DIMINISH FROM WEST TO EAST THROUGH THE OVERNIGHT HOURS. A FAIRLY LARGE TEMPERATURE GRADIENT SHOULD SET UP OVER THE REGION GIVEN THE PLACEMENT OF THE WARM FRONT ACROSS OUR AREA. HIGHS SHOULD RANGE FROM THE LOWER 60S ACROSS THE NORTHWEST TO THE MID 70S FURTHER SOUTHEAST. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE MID/UPPER 50S. -KRD && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 PM SATURDAY... TUESDAY THROUGH WEDNESDAY NIGHT...THE SHORTWAVE WILL PUSH OFFSHORE ON TUESDAY BUT WILL LEAVE A SHEAR AXIS BEHIND OVER THE REGION. THIS COUPLED WITH DECENT LOW LEVEL RESIDUAL MOISTURE AND SOME OVERRUNNING WILL RESULT IN CONTINUED CLOUDY CONDITIONS AND POSSIBLY PATCHY DRIZZLE. ALL OF THESE FEATURES WILL GRADUALLY WEAKEN BY WEDNESDAY AND THEREFORE WE SHOULD SEE A SLOW IMPROVEMENT IN OUR WEATHER CONDITIONS. GIVEN THE EXTENSIVE CLOUDS AND POSSIBLE DRIZZLE...TEMPS SHOULD HOLD IN THE MID/UPPER 60S ON TUESDAY...THEN SLIGHTLY WARMER ON WEDNESDAY. THURSDAY THROUGH SATURDAY...SHORTWAVE RIDGING WILL BUILD OVER THE REGION THROUGH THE END OF THE WEEK AS A DEEP TROUGH SETS UP OVER THE WESTERN US. THIS WILL LEAD TO DRY CONDITIONS AND A GRADUAL WARMING TREND...WITH LOW TO MID 70S EXPECTED BY THE END OF THE PERIOD. THIS TROUGH WILL EVENTUALLY BE KICKED TO THE NORTHEAST AS ANOTHER NORTHERN STREAM SYSTEM PUSHES TOWARDS THE GREAT LAKES. THIS SYSTEM WILL BE OUR NEXT WEATHER MAKER AS A FRONT IMPACTS THE AREA INTO NEXT WEEKEND. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 715 PM SATURDAY... DIFFICULT AVIATION FORECAST WITH UNCERTAINTY IN THE TIMING AND AMOUNT OF RAIN...AND ITS EFFECT ON CEILINGS. THE 18Z GFS GUIDANCE IS MUCH MORE PESSIMISTIC IN TERMS OF CHANCES FOR RAIN AND SUB-VFR CONDITIONS THROUGHOUT CENTRAL NORTH CAROLINA VERY LATE TONIGHT AND THROUGH THE DAY SUNDAY. HOWEVER...SOME OF THE HIGH-RESOLUTION MODEL GUIDANCE...ALONG WITH SREF PROBABILITIES...WHILE GENERALLY HIGH WITH PRECIPITATION CHANCES ARE LIGHT WITH QPF AND LOWER IN THE PROBABILITIES OF LOWER CEILINGS UNTIL THE WINDS BACK AHEAD OF THE WARM FRONT LATE SUNDAY. FOR THIS FORECAST...BASED ON THE LATEST RADAR TRENDS...HAVE INTRODUCED VERY LIGHT RAIN AND AREAS OF MVFR CEILINGS BY LATE TONIGHT...CONTINUING INTO SUNDAY MORNING. FROM THERE...BY LATE MORNING INTO THE AFTERNOON...MODEL SOUNDINGS SHOW SOME MID-LEVEL DRYING WHICH MAY ACTUALLY HELP PUSH CEILINGS BACK MOSTLY TO VFR IN A LOW-LEVEL...ALBEIT LIGHT...SOUTHWEST WIND. CONSENSUS OF GUIDANCE WOULD SUGGEST THE IMMEDIATE TRIAD HAS A BETTER CHANCE OF STAYING BELOW VFR...MORE LIKELY MVFR...DURING THE DAY... HOWEVER. LATE IN THE DAY...AS MUCH OF THE MODEL GUIDANCE SHOWS LOW- LEVEL WINDS BACKING AHEAD OF THE WARM FRONT MOVING NORTH THROUGH SOUTH CAROLINA...CEILINGS SHOULD START TO FALL MORE UNIFORMLY THROUGH CENTRAL NORTH CAROLINA. BY THE END OF THE DAY SUNDAY...OR SHORTLY BEYOND THIS 00Z VALID TAF PERIOD...AVIATION INTERESTS SHOULD BE PREPARED FOR AREAS OF RAIN AND WIDESPREAD IFR CONDITIONS. BEYOND THE 00Z VALID TAF PERIOD...IFR CONDITIONS ARE EXPECTED SUNDAY NIGHT INTO AT LEAST EARLY TUESDAY. OVERNIGHT SUNDAY IN PARTICULAR...THERE LIKELY WILL BE SHARP VEERING OF WINDS ALOFT WITH AN INCREASE IN SPEED TO AROUND 40KT FROM THE SOUTHWEST BY 3000FT. CEILINGS SHOULD AT LEAST IMPROVE TO MVFR TUESDAY AS LOW-LEVEL MOISTURE LINGERS WHILE MID- AND UPPER-LEVEL MOISTURE DIMINISHES. SOME BRIEF VFR CONDITIONS ARE POSSIBLE TUESDAY AFTERNOON INTO TUESDAY NIGHT BEFORE THE PROBABILITY OF SUB-VFR CONDITIONS BECOMES HIGH AGAIN LATE TUESDAY NIGHT INTO WEDNESDAY. VFR CONDITIONS GRADUALLY RETURN IN CENTRAL NORTH CAROLINA THURSDAY...LIKELY EARLIEST IN THE TRIAD AND LATER TOWARD KRWI. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...WSS SHORT TERM...VINCENT/KRD LONG TERM...KRD AVIATION...DJF  FXUS62 KRAH 011130 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 630 AM EST SUN NOV 1 2015 .SYNOPSIS...A WARM FRONT WILL MOVE NORTH INTO THE CAROLINAS TODAY AND TONIGHT...AND STALL OUT AS A LOW PRESSURE SYSTEM TRACKS ALONG THE FRONT THROUGH MONDAY. THIS STORM SYSTEM WILL MOVE SLOWLY EAST OUT OF THE AREA BY MIDWEEK. && .NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 140 AM SUNDAY... TODAY: STORMY WEATHER TO START OUT NOVEMBER WITH TODAY'S ARRIVAL OF RAINFALL ROUND ONE OF TWO (AND THE TAMER OF THE TWO). A POLAR STREAM COLD FRONT NOW SWEEPING EAST THROUGH THE ERN GREAT LAKES WILL MERGE WITH A NORTHWARD-MOVING WARM FRONT ACROSS GA/SC TO FORM A DIFFUSE FRONTAL ZONE OVER CENTRAL/ERN NC TODAY. A PERIOD OF SHALLOW MOIST UPGLIDE (ACCOMPANYING THE 850 MB SWRLY JETLET... WHICH WEAKENS AS IT SLIDES EASTWARD) WILL BE MOST PROMINENT OVER WRN NC TODAY... MUCH WEAKER AS YOU HEAD EAST WHERE MOISTURE WILL BE A BIT LESS DEEP THAN IN THE WRN PIEDMONT. FORCING FOR ASCENT OVER WRN NC WILL ALSO INCLUDE SHEARED DPVA AND UPPER DIVERGENCE ASSOCIATED WITH THE UPPER JET STREAK FROM THE TN VALLEY THROUGH THE ERN OH VALLEY TO OVER/OFF NEW ENGLAND. WILL HOLD ONTO GENERAL EXISTING TREND TOWARD INCREASING POPS FROM WEST TO EAST THROUGH THE DAY ACROSS CENTRAL NC... WITH HIGHER POPS AND GREATER QPF NORTHWEST AND LOWER SOUTHEAST... AWAY FROM THE BETTER DYNAMIC FORCING. BUT STILL EXPECT EVERYWHERE TO SEE SOME RAINFALL TODAY GIVEN THE INCREASE IN PW TO WELL ABOVE NORMAL LEVELS (1.7-2.0"). WILL TREND TOWARD LIKELY TO CATEGORICAL POPS BY MIDDAY. LATEST STATISTICAL GUIDANCE SUPPORTS EARLIER FORECASTS WITH BELOW NORMAL HIGHS OVER ALL BUT THE FAR SE WHICH SHOULD GET INTO THE WARM SECTOR AHEAD OF THE STRENGTHENING LOW LEVEL FRONTAL ZONE. HIGHS 62-70 EXCEPT LOWER 70S IN THE FAR SE. TONIGHT: AFTER A DIP IN RAIN CHANCES EARLY TONIGHT... THE MORE SUBSTANTIAL ROUND TWO OF RAIN WITH THIS STORM SYSTEM WILL ARRIVE. A RELATIVE RAIN LULL IS EXPECTED ESPECIALLY OVER THE NRN CWA LATE TODAY AND INTO THE EVENING AS THE INTENSITY OF THE LIFT DROPS OFF... OUT AHEAD OF THE INTENSIFYING SURFACE LOW TRACKING NE OVER SE LA INTO MS/AL. EXPECT POPS TO TAPER DOWN TO GOOD CHANCE TO LIKELY... HIGHEST SOUTH... LATE THIS AFTERNOON THROUGH THE EVENING. BUT THEN... LATER TONIGHT... AS THE SURFACE LOW APPROACHES FROM THE SW WITH THE FRONTAL ZONE STRENGTHENING OVER THE SANDHILLS AND COASTAL PLAIN OF NC... A 30-40 KT SOUTHWESTERLY LOW LEVEL JET WILL EMERGE OUT OF THE NORTH CENTRAL GULF AND PUNCH NNE WITH ITS NOSE ALONG THE FRONT JUST OUT AHEAD OF THE SURFACE LOW. PW WILL INCREASE A LITTLE MORE TO NEAR-RECORD HIGH VALUES OF 1.8-2.1"... AND MODELS SHOW A RESURGENCE OF EVEN DEEPER AND STRONGER MOIST ISENTROPIC UPGLIDE UP AND OVER THE SURFACE FRONTAL ZONE... FOCUSED OVER WRN AND FAR SW NC LATE TONIGHT. WILL SPREAD HIGH POPS (CATEGORICAL) BACK INTO THE CWA FROM THE SW AFTER MIDNIGHT... WITH RAIN COVERING NEARLY ALL OF THE PIEDMONT BY MORNING. MODELS ARE IN GENERALLY GOOD AGREEMENT ON QPF WITH THIS FIRST ROUND OF RAIN AND THE BEGINNING OF THE SECOND ROUND... AND THE SREF AGREES ON TIMING AND PLACEMENT WITH PROBABILITIES OVER 50% OF A QUARTER INCH OR MORE OF RAIN IN 3 HRS IN THE NW HALF OF THE CWA THROUGH TONIGHT. EXPECT RAINFALL TO TOTAL A QUARTER TO AS MUCH AS AN INCH AND A HALF IN THE SW CWA TODAY THROUGH TONIGHT. EXPECT LOWS IN THE UPPER 50S TO LOWER 60S... YIELDING A SMALL DIURNAL RANGE FROM TODAY WITH CLOUDY SKIES. -GIH && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 220 AM SUNDAY... MON/MON NIGHT: MODELS HAVE COME INTO BETTER AGREEMENT ON THE EVOLUTION OF THIS STORM SYSTEM... DEPICTING A SURFACE LOW MOVING FROM NRN AL EARLY MON ENE ALONG THE FRONTAL ZONE (ALTHOUGH WE'RE LIKELY TO SEE THE PRIMARY LOW WEAKENING AS IT APPROACHES THE MOUNTAINS WITH NEW LOWS FORMING DOWNSTREAM ALONG THE FRONT)... WHILE A POTENT BUT DAMPENING SHORTWAVE TROUGH TRACKS ENE THROUGH THE REGION. THE GFS AND ECMWF SHOW A MORE SOUTHEASTWARD POSITION OF THE SURFACE FRONT WITH STABLE AIR ASSOCIATED WITH THE WEAK BUT COOL HIGH TO OUR NORTH COVERING MORE OF THE CWA (ESPECIALLY THE NORTHWEST AND FAR NRN CWA) THAN THE NAM... WHICH HAS A STRONGER PRIMARY SURFACE LOW AND AS SUCH PENETRATES THE FRONT FURTHER NORTHWARD INTO NC. A SLIGHTLY WEAKER LOW... REFLECTIVE OF THE MORE SHEARED AND LESS CONCENTRATED MID LEVEL VORTICITY MAX IN THE BASE OF THE APPROACHING SHORTWAVE TROUGH... IS PREFERRED THIS MORNING. BUT NEVERTHELESS WE SHOULD SEE STRONG FORCING FOR ASCENT INCLUDING THE STRONG LOW LEVEL OVERRUNNING FLOW UP AND OVER THE SURFACE FRONT... MID LEVEL DPVA (ALTHOUGH AGAIN THIS WILL BE WEAKENING AS THE WAVE DAMPENS)... AND PASSAGE OF AN UPPER DIVERGENCE MAXIMUM. WILL CONTINUE WITH CATEGORICAL POPS AREAWIDE MON MORNING... WITH HIGHEST POPS SHIFTING NORTHWARD TO THE FAR NRN/WRN PIEDMONT AS THE 850 MB WARM FRONTAL ZONE SHIFTS NORTHWARD IN CONJUNCTION WITH THE NORTHWARD SHIFT OF THE STRONGEST AND DEEPEST MOIST ISENTROPIC UPGLIDE. THIS MAY RESULT IN A RELATIVE LULL IN COVERAGE AND INTENSITY SOUTH AND EAST OF THE TRIANGLE LATE MON MORNING THROUGH MID AFTERNOON... WITH MORE WIDESPREAD RAIN CONTINUING FROM THE TRIANGLE NORTH AND WEST. THEN... WILL TRANSLATE THESE HIGH POPS EASTWARD WITH WAVE PASSAGE MON NIGHT. EVEN TAKING A CONSERVATIVE APPROACH USING JUST A FRACTION OF MODEL QPF STILL SUGGESTS ADDITIONAL RAINFALL OF 1 TO 2 INCHES MON THROUGH MON NIGHT... AND LOCALLY HIGHER AMOUNTS ARE CERTAINLY POSSIBLE. WILL CONTINUE A MENTION OF THIS HEAVY RAIN THREAT IN THE HAZARDOUS WEATHER OUTLOOK. AGAIN EXPECT A LIMITED DIURNAL RANGE... WITH MON HIGHS OF 60-70 EXCEPT LOWER 70S FAR SE IN THE WARM SECTOR. EXPECT RAIN TO TAPER DOWN WEST TO EAST LATE MON NIGHT AS THE SURFACE LOWS SHIFT TO OUR EAST AND SE... WITH SOME DRYING TAKING PLACE ALOFT AND A SHUTTING DOWN OF MOIST UPGLIDE. EXPECT LOWS IN THE 50S. TUE/TUE NIGHT: THE HEAVY RAIN THREAT WILL BE DECREASING BUT THE CHANCE FOR LIGHT RAIN WILL PERSIST... ALONG WITH THICK LOW CLOUD COVER. THE SURFACE FRONTAL ZONE APPEARS LIKELY TO HOLD JUST SOUTH AND EAST OF THE FORECAST AREA WITH THE 850 MB FRONTAL ZONE STRETCHING WSW-ENE ACROSS NC... AND THE WEAK BUT COOL SURFACE HIGH CENTERED TO OUR NORTH EXTENDING DOWN ALONG THE EAST SLOPES AND ADJACENT FOOTHILLS AND NW PIEDMONT THROUGH TUE NIGHT. MOIST UPGLIDE WEAKENS BUT PERSISTS BELOW 800 MB (295K)... WHERE MODELS DEPICT A STABLE AND NEARLY SATURATED ATMOSPHERE. WILL HAVE TO RETAIN A CHANCE OF LIGHT RAIN OR DRIZZLE TUE AREAWIDE... A BIT HIGHER EAST OF I-95 WHERE THE SURFACE-BASED MOIST LAYER WILL BE DEEPEST... BUT ADDITIONAL QPF WILL BE QUITE LOW. EXPECT A CHILLY DAY WITH HIGHS TUE IN THE 60S AREAWIDE (UPPER 50S POSSIBLE IN THE NW CWA). LOWS TUE NIGHT IN THE 50S. -GIH && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 245 AM SUNDAY... IN THE WAKE OF THE EXITING LOW PRESSURE SYSTEM OFF OF THE COAST...A ROBUST SURFACE HIGH WILL MOVE ACROSS NEW ENGLAND AND EXTEND DOWN INTO THE CAROLINAS...SETTING UP THE POTENTIAL FOR A WEAK COLD AIR DAMMING SCENARIO. ALTHOUGH ISENTROPIC LIFT APPEARS TO BE MINIMAL...THE PATTERN SUGGESTS AT LEAST CLOUDY CONDITIONS...IF NOT SOME LIGHT RAIN OR DRIZZLE...CONTINUING THROUGH WEDNESDAY...GRADUALLY WEAKENING WITH TIME. THIS WILL KEEP HIGH TEMPS DOWN ON WEDNESDAY (UPPER 60S TO LOWER 70S). BY THURSDAY MORNING THE SURFACE HIGH PUSHES OFF SHORE AND DAMMING WILL WEAKEN...WITH SOME CLOUDS REMAINING THROUGH MORNING...PARTICULARLY IN THE WEST. A RELATIVELY WEAK SURFACE HIGH WILL FORM OVER THE WESTERN CAROLINAS AND WILL BE THE CATALYST FOR WARMER AND DRIER WEATHER FOR THE END OF THE WORK WEEK. EXPECT A WARMING TREND WITH HIGH TEMPS IN THE LOW TO MID 70S THROUGH SATURDAY. NIGHTTIME LOWS GENERALLY IN THE 50S. A FRONTAL SYSTEM WILL APPROACH FOR THE END OF THE WEEK BUT MODEL SOLUTIONS DIFFER AT THIS TIME WITH THE TIMING OF THE SYSTEM. THE GFS SOLUTION HAS THE FRONT MOVING THROUGH QUICKER...WHEREAS THE ECMWF HOLDS IT BACK. WILL INTRODUCE SLIGHT CHANCE POPS ON SATURDAY BUT HOLD OFF ON TOO MANY DETAILS UNTIL FURTHER RUNS OF THE MODELS ADD CONFIDENCE TO THE FORECAST. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 630 AM SUNDAY... 24 HOUR TAF PERIOD: LIGHT RAIN FINALLY STARTING TO MAKE IT TO THE SURFACE IN THE TRIAD WITH KINT AND KGSO BOTH REPORTING LIGHT RAIN AT THIS HOUR. TO THE EAST HOWEVER...RAIN HAVING A HARD TIME REACHING THE SURFACE THROUGH THE DRY MID-LEVELS. THUS THE TRIAD SITES ARE SHOWING MVFR CONDITIONS AT THIS HOUR WITH CEILINGS DROPPING BUT ALL OTHER TAF SITES REMAIN AT VFR. CEILINGS AND RAINFALL WILL WORK FROM WEST TO EAST SO DESPITE THE DELAY IN THE ONSET...ALL SITES WILL EVENTUALLY SEE SUB-VFR CONDITIONS TODAY WITH IFR/LIFR PROBABLE OVERNIGHT TONIGHT. WITH THE MAIN SYSTEM WELL OFF TO THE SOUTHWEST...ONCE CONDITIONS DEGRADE...THEY WILL REMAIN SO THROUGH THE END OF THE TAF PERIOD. WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE AND CEILINGS THE MAIN PROBLEM FOR AVIATION CONDITIONS ALTHOUGH MVFR VISIBILITIES WILL ALSO BE A PROBLEM AT MOST SITES LATER TODAY. LONG TERM: ADVERSE CONDITIONS WILL INITIATE TODAY AND REMAIN SUB-VFR POTENTIALLY THROUGH TUESDAY. SOME RESIDUAL MOISTURE IS POSSIBLE THROUGH MIDWEEK AND THEN A GENERALLY DRY PERIOD BEFORE THE NEXT FRONTAL SYSTEM APPROACHES THE AREA NEXT WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ELLIS NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...ELLIS AVIATION...ELLIS  FXUS62 KRAH 090529 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1230 AM EST SAT JAN 09 2016 .SYNOPSIS...A RIDGE OF COOL HIGH PRESSURE AT THE SURFACE WITH PLENTIFUL MOISTURE ALOFT WILL KEEP UNSETTLED WEATHER THROUGH SATURDAY NIGHT... AS A STRONG STORM SYSTEM APPROACHES FROM THE WEST AND MOVES THROUGH THE REGION. THIS SYSTEM WILL EXIT ON SUNDAY WITH CLEARING SKIES AND DRIER WEATHER THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... THE ENTIRE AREA REMAINS WEDGED IN TONIGHT AS HIGH PRESSURE CONTINUES TO EXTEND DOWN THE EAST SIDE OF THE APPALACHIANS. EVEN THOUGH THE BEST FORCING HAS PUSHED OFF TO THE NORTHEAST...HIGH LOW LEVEL MOISTURE BENEATH THE INVERSION HAS LEAD TO PERSISTENT DRIZZLE. IN ADDITION...AS ONE WOULD EXPECT WITHIN THE COLD AIR DAMMING REGIME... WIDESPREAD LOW STRATUS AND FOG ARE ALSO OCCURRING. MOST GUIDANCE IS INDICATING THAT THE FOG WILL BECOME DENSE AFTER MIDNIGHT AND IF IT DOES OCCUR...IT COULD PERSIST INTO THE LATE MORNING HOURS OF SATURDAY. VISIBILITY TRENDS WILL CONTINUE TO BE MONITORED CLOSELY OVER THE NEXT SEVERAL HOURS AND A DENSE FOG ADVISORY MAY INDEED BE NEEDED. REGARDLESS...VISIBILITIES WILL NOT BE GREAT AND EXTRA CAUTION SHOULD BE TAKEN. TEMPS WILL NOT FALL ALL THAT MUCH GIVEN THE THICK CLOUD COVER AND OVERNIGHT LOWS ARE EXPECTED TO BE IN THE UPPER 30S TO LOWER 40S. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 245 PM FRIDAY... THE NEXT SYSTEM APPROACHING IN THE SOUTHERN BRANCH JET STREAM WILL APPROACH FROM THE TENNESSEE VALLEY REGION BY LATE SATURDAY. OUT AHEAD OF THE SYSTEM... THE CAD WILL LINGER SATURDAY WITH AREAS OF FOG/DRIZZLE THROUGHOUT THE MORNING WITH LITTLE TEMPERATURE MOVEMENT IN THE 40S. RAIN IS EXPECTED TO DEVELOP DURING THE AFTERNOON AS THE COASTAL/CAD BOUNDARY TRIES TO ADVANCE INTO THE COASTAL AREA... AND POSSIBLY THE SE COASTAL PLAIN BY EVENING... AND THE NEGATIVELY TILTED MID/UPPER LOW APPROACH FROM THE SW. HIGHS WILL OCCUR DURING THE EVENING AS THIS PROCESS OCCURS. TEMPERATURES MAY NOT CHANGE MUCH AT ALL OVER THE CAD REGION OF THE PIEDMONT AND WILL NOT REACH HIGHS UNTIL EVENING (UPPER 40S TO MID 50S). FOR THE COASTAL PLAIN... THERE IS A CONDITIONAL (AND CURRENTLY MARGINAL RISK OF SEVERE THUNDERSTORM WIND GUSTS/POSSIBLY ISOLATED TORNADO) DURING THE VERY LATE AFTERNOON THROUGH THE EVENING. THIS INCLUDES AREAS AS FAR INLAND AS LAURINBURG TO FAYETTEVILLE TO GOLDSBORO TO TARBORO. THE THREAT OF THUNDERSTORMS AND SEVERE WEATHER IS CONDITIONAL TO WHERE THE BOUNDARY CAN PENETRATE INLAND. IF RAIN BECOMES WIDESPREAD (WHICH WE THINK IT WILL) SATURDAY AFTERNOON... THIS WOULD KEEP THE BOUNDARY LAYER MUCH MORE STABLE AND KEEP THE CAD FROM ERODING QUICKLY ENOUGH AND/OR HELP KEEP THE BOUNDARY LAYER STABLE ENOUGH TO PRECLUDE SURFACE BASED CONVECTION. IF THE COASTAL BOUNDARY CAN PENETRATE INTO OUR SE COASTAL PLAIN... THEN CONDITIONS WOULD BE MUCH MORE FAVORABLE (LOWER 60S DEW POINTS) AND RESULTANT INSTABILITY TO GO ALONG WITH THE INCREASINGLY STRONG WIND SHEAR (50KT OF EFFECTIVE SHEAR AND FAVORABLE LOW LEVEL HODOGRAPHS). THIS WOULD ALLOW FOR THE POTENTIAL FOR A FEW SEVERE STORMS ALONG THE BOUNDARY AND/OR TRIPLE POINT LATER IN THE EVENING. THE MAIN FRONT WILL ARRIVE BETWEEN 06Z-12Z FROM THE WEST WHICH WILL CUT OFF THE SHOWERS/POTENTIAL STORMS IN THE SE THEN. LOWS WILL NOT FALL MUCH WITH READINGS LIKELY STILL NEAR 60 IN THE SE AROUND 12Z/SUNDAY... WITH 40S IN THE WEST. QPF OF 0.50 TO LOCALLY 1 INCH IS EXPECTED. THE LATEST GUIDANCE FROM THE RIVER FORECAST CONCERNING FLASH FLOOD POTENTIAL DURING THE EVENT IS NOT LOW ENOUGH FOR A WATCH AT THE PRESENT TIME. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 325 PM FRIDAY... LOOK FOR SUBSIDENCE AND CLEARING WEATHER ON SUNDAY IN THE WAKE OF SATURDAY NIGHT'S DEPARTING SHORT WAVE. FORECAST SOUNDINGS AND MODEL PROGS SHOWS A TRAILING DRY COLD FRONT MOVING ACROSS CENTRAL NC DURING THE LATE AFTERNOON SUNDAY. UNTIL FROPA...HIGHS SUNDAY WILL REMAIN ABOVE NORMAL...55-65...WARMEST EAST. MODIFIED HIGH PRESSURE COMING IN FROM THE WEST WILL SET UP ACROSS THE CAROLINAS FOR MONDAY AND EARLY TUESDAY. TEMPS DURING THIS TIME WILL BE CLOSE TO NORMAL (UPPER 20S FOR LOWS AND HIGHS UPPER 40S TO AROUND 50). BY LATE TUESDAY...A POLAR FRONT WILL DROP SE ACROSS THE OHIO VALLEY AND IS PROGGED TO SWEEP ACROSS CENTRAL NC A FEW HOURS EITHER SIDE OF MIDNIGHT TUESDAY NIGHT. MOISTURE ASSOC WITH THIS FRONT IS PROGGED TO DRY UP AFTER IT CROSSES THE MOUNTAINS...SO AT BEST...PERHAPS A FLURRY OR TWO MAY BE POSSIBLE ACROSS OUR FAR NORTHERN ZONES NEAR THE VA BORDER...BUT ATTM NOT EXPECTING ANY WIDESPREAD MEASURABLE PRECIP. DRY COLDER WEATHER WED AND THU AS HIGH PRESSURE BUILDS ACROSS THE CAROLINAS. HIGHS ON WED IN THE MID 30S...AND MID 40S ON THU. LOWS IN THE 20S BOTH DAYS. BOTH GFS AND NOW THE 12Z ECMWF SUGGEST A FAST-MOVING SRN STREAM S/W WILL APPROACH AND/OR AFFECT CENTRAL NC ON FRIDAY WITH LIGHT QPF AMOUNTS. BY THIS TIME...THE AIRMASS IS EXPECTED TO MODERATE ENOUGH TO SUPPORT AN ALL-LIQUID EVENT...HOWEVER GFS FORECAST SOUNDINGS SUGGEST A FEW SNOW FLAKES AT THE ONSET GIVEN EVAP COOLING...BUT QUICKLY TURNING TO ALL-RAIN GIVEN WEAK NATURE OF STORM THAT WOULD NOT BE ABLE TO OVERCOME THE SUBSTANTIAL BL WARMING. AT THIS POINT...WAY TOO FAR OUT IN TIME TO GET OVERLY EXCITED...ESP GIVEN THE FACT THAT THE MODELS HAVE HAD A TOUGH TIME WITH RUN-TO-RUN CONSISTENCY LATELY...AND DETAILS WILL INEVITABLY CHANGE! && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 1230 AM SATURDAY... ...WIDESPREAD FOG OVERNIGHT THROUGH SATURDAY MORNING... HIGH CONFIDENCE IN ADVERSE AVIATION CONDITIONS TONIGHT THROUGH MUCH OF SAT MORNING... WITH ONLY SLOW IMPROVEMENT THEREAFTER. A WEDGE OF COOL HIGH PRESSURE WILL CONTINUE TO NOSE IN FROM THE NE AT THE SURFACE... WHILE DEEP MOISTURE STREAMS INTO THE AREA JUST OFF THE SURFACE. THIS WILL KEEP DEEP LOW IFR/LIFR CLOUDS OVER THE REGION WITH WIDESPREAD IFR FOG... SOME OF IT NEARING LIFR/VLIFR LATE TONIGHT. THE STAGNANT AIR MASS AND CLOUD DEPTH WILL KEEP THESE ADVERSE CONDITIONS LOCKED IN LONGER THAN USUAL SAT MORNING... AS IT MAY BE LATE MORNING OR THE NOON HOUR BEFORE WE ACHIEVE MVFR CONDITIONS AT CENTRAL NC AIRFIELDS. AN APPROACHING STORM SYSTEM FROM THE SOUTH AND SW WILL THEN BRING INCREASING CHANCE FOR SHOWERS AND ISOLATED STORMS STARTING SAT AFTERNOON AND LASTING THROUGH SAT NIGHT... WITH CONDITIONS AGAIN DETERIORATING TO IFR LATE SAT AFTERNOON THROUGH SAT NIGHT. AVIATION INTERESTS SHOULD BE ALERT FOR STRONG WINDS FROM THE SE AT 1500-3000 FT AGL PRECEDING THE FRONT SAT NIGHT... PARTICULARLY AS WE APPROACH 06Z. LOOKING BEYOND 06Z SAT NIGHT... POOR AVIATION CONDITIONS WILL PERSIST UNTIL PASSAGE OF A COLD FRONT FROM WEST TO EAST LATE SAT NIGHT INTO SUN MORNING. THE STRONG WINDS FROM THE SE JUST OFF THE GROUND WILL CONTINUE TO INCREASE AND VEER TO SOUTHERLY OR SOUTHWESTERLY LATE SAT NIGHT INTO SUN MORNING. THUNDERSTORMS ARE POSSIBLE SAT NIGHT ESPECIALLY AFFECTING RWI/FAY. CLEARING SKIES AND A TREND TO VFR ARE EXPECTED SUNDAY... ALTHOUGH STRONG GUSTY WINDS FROM THE WEST ARE LIKELY POST-FRONT. VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH WED... ALTHOUGH GUSTY WINDS MAY RETURN WITH A DRY COLD FRONT PASSAGE TUE NIGHT/WED. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...KRD SHORT TERM...BADGETT LONG TERM...RAH AVIATION...HARTFIELD  FXUS62 KRAH 090745 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 245 AM EST SAT JAN 09 2016 .SYNOPSIS...A RIDGE OF COOL HIGH PRESSURE AT THE SURFACE WITH PLENTIFUL MOISTURE ALOFT WILL KEEP UNSETTLED WEATHER THROUGH SATURDAY NIGHT... AS A STRONG STORM SYSTEM APPROACHES FROM THE WEST AND MOVES THROUGH THE REGION. THIS SYSTEM WILL EXIT ON SUNDAY WITH CLEARING SKIES AND DRIER WEATHER THROUGH EARLY NEXT WEEK. && .NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 240 AM SATURDAY... THROUGH THIS MORNING... WIDESPREAD FOG AND THICK STRATUS ARE LIKELY TO PERSIST WITHIN THE WEDGE REGIME... FEATURING A DAMMING SURFACE HIGH CENTERED OFF THE CANADIAN MARITIMES NOSING SW INTO NC... CAPPED BY WEAK BUT STEADY MOIST UPGLIDE. BLOCKED BY THE MOUNTAINS TO THE WEST AND A FRONTAL ZONE WELL TO OUR SOUTH AND SE... THE WEDGE SHOULD STAY LOCKED IN WELL INTO THE MORNING GIVEN THE STAGNANT SURFACE AIR... PROFOUND CLOUD DEPTH... AND LACK OF ANY MECHANISM TO DISPERSE IT IN THE VERTICAL. THE HRRR AND HRRR-X ARE STILL SHOWING INCREASING FOG DENSITY THROUGH DAYBREAK... AND WHILE THIS IS FAR FROM CERTAIN GIVEN THE EXTENT OF STRATUS... WILL KEEP A CLOSE EYE ON FOG TRENDS... AND DENSE FOG ADVISORY MAY BE NEEDED THIS MORNING. THE MOIST UPGLIDE DOESN'T APPEAR TO BE STRONG OR DEEP ENOUGH FOR ANYTHING MORE THAN PATCHY DRIZZLE OVER THE NEXT SEVERAL HOURS... AND OTHER FORCING MECHANISMS ARE LACKING AS WELL GIVEN THE DEPARTURE TO OUR NE OF A BATCH OF MID LEVEL VORTICITY... SO POPS THROUGH THIS MORNING WILL BE LOW. TEMPS WILL BE SLOW TO RISE THROUGH THE UPPER 40S AND LOW-MID 50S THIS MORNING. MIDDAY TODAY THROUGH TONIGHT: THE ACTIVE SOUTHERN STREAM REACHES ITS PEAK IMPACT ON THE SOUTHEAST STATES LATE THIS AFTERNOON AND TONIGHT WITH PASSAGE OF A POTENT MID LEVEL SHORTWAVE TROUGH AND SURFACE LOW TO OUR WEST AND NW... MOVING FROM THE LOWER MISS VALLEY NEAR MIDDAY THROUGH THE TN AND ERN OH VALLEY THROUGH TONIGHT. WHILE THE CHANCE OF EVERYONE SEEING AT LEAST SOME SHOWERS (AND PERHAPS A STORM OR TWO... MORE ON THAT LATER) IS HIGH CONSIDERING THE PROJECTIONS OF MUCH ABOVE NORMAL PW (0.90-1.20")... IT APPEARS THAT THE BULK OF THE DYNAMIC FORCING FOR ASCENT WILL HOLD TO OUR WEST AND NORTH. THESE MECHANISMS INCLUDES THE MID LEVEL DPVA WITH THE SHORTWAVE TROUGH AS WELL AS THE STRONGEST UPPER DIVERGENCE WITH THE LEFT EXIT REGION OF THE SUBTROPICAL JET... BOTH OF WHICH TAKE A PATH NW OF CENTRAL NC. BUT THERE SHOULD STILL BE A STRONG INFLUX OF LOWER LEVEL MOISTURE... FOCUSED INTO CENTRAL AND ERN NC OUT AHEAD OF A WEAK SURFACE LOW NOW OVER SOUTH FLA AND EXPECTED TO TRACK NORTHWARD TODAY AND THROUGH CENTRAL NC TONIGHT... DRAWING ENOUGH ATLANTIC MOISTURE INTO THE AREA FOR A PERIOD OF CATEGORICAL POPS... FOCUSING LATE AFTERNOON THROUGH TONIGHT... WITH GREATEST COVERAGE AND DURATION OCCURRING ACROSS THE NRN AND ERN FORECAST AREA. AS THIS SURFACE LOW APPROACHES AND DRAWS THE COASTAL WEDGE FRONT WESTWARD INTO THE NC COASTAL PLAIN THIS EVENING/TONIGHT... WEAK INSTABILITY (PEAKING AT A MUCAPE OF ABOUT 500-1000 J/KG TONIGHT) ALONG WITH IMPRESSIVE DEEP LAYER SHEAR AOA 50 KTS COULD SUPPORT A FEW POCKETS OF STRONGER CONVECTION... MOST LIKELY (ACCORDING TO THE LATEST MODEL RUNS) DURING THE EARLY TO MID EVENING HOURS. IT'S UNCLEAR WHETHER OR NOT ANY WEAK INSTABILITY WILL BE ACHIEVED DURING THE TIME OF GREATEST LOW LEVEL SHEAR (0-3 KM SRH PREDICTED TO REACH 300-400 M2/S2 ON THE NAM AND ABOUT HALF THAT ON THE GFS)... WHICH WOULD INFLUENCE THE THREAT OF SUPERCELLS. SUCH A SCENARIO SEEMS UNLIKELY BUT THE POTENTIAL WILL BE MONITORED. IF SURFACE DEWPOINTS OVER OUR EAST CLIMB INTO THE UPPER 50S TO AROUND 60 AS EXPECTED HOWEVER... WITH WINDS BECOMING MORE UNIDIRECTIONAL (A STRAIGHTENING HODOGRAPH)... THERE COULD BE A RISK OF BOWING SEGMENTS AND STRONG STRAIGHT LINE WINDS TONIGHT. WILL RESTRICT AN ISOLATED MENTION OF THUNDER TONIGHT FROM RALEIGH EAST AND SOUTH... ALONG AND EAST OF THE ANTICIPATED TRACK OF THE WEAK SURFACE LOW. THE WARM/WEDGE FRONT WILL SHIFT BACK EAST OVER THE COASTAL PLAIN LATE TONIGHT AS THE OCCLUDED FRONT APPROACHES. EXPECT HIGHS FROM THE UPPER 40S TO NEAR 50 IN THE TRIAD TO NEAR 60 IN OUR FAR SE (CLINTON TO GOLDSBORO). TEMPS SHOULD SLIP JUST A FEW DEGREES EARLY TONIGHT... TO THE MID 40S NW TO MID-UPPER 50S SE... WITH STEADY TEMPS OR A SLIGHT RISE OVERNIGHT. -GIH && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... AS OF 245 AM SATURDAY... CONSENSUS OF THE LATEST MODELS IS TO SHIFT THE FRONTAL ZONE AND ATTENDANT PRECIP EAST OUT OF THE COASTAL PLAIN SUN MORNING... WITH THE ONSET OF BRISK AND GUSTY SW WINDS... SHIFTING TO WESTERLY LATE IN THE DAY... AS THE SECONDARY COLD FRONT (TRAILING THE POTENT SURFACE LOW THAT WILL ACCOMPANY THE VORTICITY/UPPER DIVERGENCE MAX UP THROUGH LAKE ERIE/LAKE ONTARIO) PUSHES EAST INTO THE AREA LATE. LOW LEVEL THICKNESSES START TO DROP SUNDAY MORNING BUT WILL INITIALLY BE OFFSET BY INCREASING SUNSHINE AND THE DELAY IN COLD AIR ADVECTION. HIGHS SHOULD BE IN THE MID 50S TO LOWER 60S EARLY IN THE DAY... WITH READINGS SLIPPING LATER IN THE DAY. WITH THE TIGHT MSLP GRADIENT IN THE WAKE OF THE LAKE ERIE LOW... SUSTAINED WINDS OF 15- 20 KTS APPEAR LIKELY... WITH FREQUENT GUSTS TO AROUND 30 MPH... BOTH LIGHTENING UP LATE IN THE DAY. MOSTLY CLEAR SUN NIGHT WITH DIMINISHING WINDS AND WINDS BECOMING WNW AS COLDER AIR RUSHES IN. LOWS 25-33. -GIH && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 AM SATURDAY... THE WORK WEEK BEGINS WITH HIGH PRESSURE IN PLACE OVER THE DEEP SOUTH AND SOUTHWESTERLY FLOW ALOFT WHICH WILL KEEP CENTRAL NC DRY WITH SLIGHTLY BELOW NORMAL TEMPERATURES IN PLACE AS HIGHS WILL CLIMB INTO THE LOW TO MID 40S MONDAY WITH LOWS IN THE MID TO UPPER 20S. MODERATION OF THE TEMPERATURES WILL INCREASE ON TUESDAY AS THICKNESS VALUES RISE ABOUT 15 METERS...THUS CORRESPONDING TO ABOUT A 5 DEGREE TEMPERATURE INCREASE FOR HIGHS ON TUESDAY. EXPECT MID 40S IN THE NW PIEDMONT TO NEAR 50 DEGREES IN THE SOUTHEAST. THAT IS WHERE THE MODERATION ENDS HOWEVER AS A COLD FRONT COMES RUSHING INTO THE AREA TUESDAY NIGHT AND EARLY WEDNESDAY MORNING. THIS WILL KEEP LOWS BELOW FREEZING WEDNESDAY MORNING...MID 20S TO NEAR 30 DEGREES. A VERY STRONG PRESSURE GRADIENT WILL ACCOMPANY THE FRONTAL PASSAGE AND GUSTY WINDS CAN BE EXPECTED. ACCORDING TO GFS BUFFER SOUNDINGS...GUSTS COULD BE AS HIGH AS 25 KTS BASED ON MOMENTUM TRANSFER TO THE SURFACE. RIGHT NOW MODELS REMAIN DRY...BUT A BRIEF FLURRY OR TWO CANT BE RULED OUT AS THE UPPER TROUGH MOVES THROUGH EARLY WEDNESDAY MORNING. NO IMPACTS ARE EXPECTED ASIDE FROM VERY STRONG COLD AIR ADVECTION. THIS WILL KEEP MAX TEMPERATURES DOWN IN THE UPPER 30S ACROSS THE NORTH TO LOW 40S IN THE SOUTHERN TIER. LOWS IN THE MIDDLE 20S. AFTER THE UPPER TROUGH CROSSES THE AREA WEDNESDAY MORNING...SURFACE HIGH PRESSURE OVER THE SOUTH WILL BEGIN TO MIGRATE NORTHEASTWARD OVER THE CAROLINAS...RELAXING THE PRESSURE GRADIENT. SOUTHWESTERLY FLOW ALOFT WILL ONCE AGAIN MODERATE TEMPERATURES BACK INTO THE MID TO UPPER 40S ON THURSDAY AFTERNOON WITH UPPER 20S TO LOWER 30S THURSDAY NIGHT. MODELS DIFFER IN THE APPROACH OF A LOW PRESSURE SYSTEM THAT FORMS OVER THE WESTERN GULF OF MEXICO WEDNESDAY NIGHT AND ENDS UP SOMEWHERE OFF OF THE EAST COAST ON FRIDAY MORNING. THE GFS SOLUTION KEEPS THE LOW OFF OF THE COAST ON FRIDAY BUT THE ECMWF DOUSES CENTRAL NC WITH PRECIPITATION FRIDAY MORNING. AT THIS TIME...IT APPEARS MOST OF THE PRECIPITATION WOULD BE LIQUID AS TEMPERATURES MODERATE INTO THE UPPER 40S TO LOWER 50S. AGAIN A FLURRY CANT BE RULED OUT AT THE ONSET OF PRECIPITATION IN THE NORTHWEST PIEDMONT BUT AS OF NOW THIS WOULD BE A RAIN EVENT. PLENTY OF TIME FOR THINGS TO CHANGE AS THE PARENT LOW HASN'T BEGUN TO FORM YET. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 1230 AM SATURDAY... ...WIDESPREAD FOG OVERNIGHT THROUGH SATURDAY MORNING... HIGH CONFIDENCE IN ADVERSE AVIATION CONDITIONS TONIGHT THROUGH MUCH OF SAT MORNING... WITH ONLY SLOW IMPROVEMENT THEREAFTER. A WEDGE OF COOL HIGH PRESSURE WILL CONTINUE TO NOSE IN FROM THE NE AT THE SURFACE... WHILE DEEP MOISTURE STREAMS INTO THE AREA JUST OFF THE SURFACE. THIS WILL KEEP DEEP LOW IFR/LIFR CLOUDS OVER THE REGION WITH WIDESPREAD IFR FOG... SOME OF IT NEARING LIFR/VLIFR LATE TONIGHT. THE STAGNANT AIR MASS AND CLOUD DEPTH WILL KEEP THESE ADVERSE CONDITIONS LOCKED IN LONGER THAN USUAL SAT MORNING... AS IT MAY BE LATE MORNING OR THE NOON HOUR BEFORE WE ACHIEVE MVFR CONDITIONS AT CENTRAL NC AIRFIELDS. AN APPROACHING STORM SYSTEM FROM THE SOUTH AND SW WILL THEN BRING INCREASING CHANCE FOR SHOWERS AND ISOLATED STORMS STARTING SAT AFTERNOON AND LASTING THROUGH SAT NIGHT... WITH CONDITIONS AGAIN DETERIORATING TO IFR LATE SAT AFTERNOON THROUGH SAT NIGHT. AVIATION INTERESTS SHOULD BE ALERT FOR STRONG WINDS FROM THE SE AT 1500-3000 FT AGL PRECEDING THE FRONT SAT NIGHT... PARTICULARLY AS WE APPROACH 06Z. LOOKING BEYOND 06Z SAT NIGHT... POOR AVIATION CONDITIONS WILL PERSIST UNTIL PASSAGE OF A COLD FRONT FROM WEST TO EAST LATE SAT NIGHT INTO SUN MORNING. THE STRONG WINDS FROM THE SE JUST OFF THE GROUND WILL CONTINUE TO INCREASE AND VEER TO SOUTHERLY OR SOUTHWESTERLY LATE SAT NIGHT INTO SUN MORNING. THUNDERSTORMS ARE POSSIBLE SAT NIGHT ESPECIALLY AFFECTING RWI/FAY. CLEARING SKIES AND A TREND TO VFR ARE EXPECTED SUNDAY... ALTHOUGH STRONG GUSTY WINDS FROM THE WEST ARE LIKELY POST-FRONT. VFR CONDITIONS ARE EXPECTED TO DOMINATE THROUGH WED... ALTHOUGH GUSTY WINDS MAY RETURN WITH A DRY COLD FRONT PASSAGE TUE NIGHT/WED. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...ELLIS AVIATION...HARTFIELD  FXUS62 KRAH 181431 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1030 AM EDT Wed May 18 2016 .SYNOPSIS...A cold front and attendant wave of low pressure will move off the Southeast coast later this morning. A wedge of cool surface high pressure will build over the area tonight through through Thursday. A low pressure system tracking east across the Southern states will bring wet unsettled conditions to the Carolinas Friday through early Saturday. && .NEAR TERM /through tonight/... As of 1030 AM Wednesday... Upper air analysis depict a weak low level trough over the ne sector of central NC. Weak confluence along this boundary in conjunction with modest lift aloft associated with divergence in the right entrance region of a 110+ kt jet exiting the northern Mid-Atlantic was causing spots of light rain/drizzle across sections of central NC this morning. The patches of light rain/drizzle will diminish with time and lift becomes weaker. Abundant low level moisture will be tough to scour out due to lack of sufficient mixing of drier air...thus a blanket of low stratus will persist into the afternoon hours. Area MDCRS aircraft soundings suggest the cloud thickness about a 1000ft or a little less. This suggest that some breaks may occur late in the day...though likely too late to add in temp recovery. Low overcast skies and a steady near sfc ne wind will hold temps well below normal for mid-May. Afternoon temps will top out in the mid-upper 60s north to near 70-lower 70s south. -WSS Ceilings are expected to quickly fall/lower after sunset with IFR to LIFR conditions expected everywhere overnight. Continued weak upglide along the eastern slopes of the mtns will continue to support a slight to small chance of rain, mainly across the western Piedmont. Lows tonight in the lower 50s north to upper 50s south. -CBL && .SHORT TERM /Thursday and Thursday night/... As of 345 AM Wednesday... Parent high center will build over the Mid-Atlantic Seaboard on Thursday with low-level wedge of cooler and drier air ridging south into the area underneath continued WSW flow aloft, within the right entrance region of a ~90kt upper jet streak in place over the Mid- Atlantic region. Low clouds/moisture will persist but sufficient forcing is absent over the area during the day on Thursday. So expect a gray gloomy day across the area with continued below normal temperatures in the mid/upper 60s north to lower 70s south. Weak upglide begins to strengthen Thursday night, in response to mid- level shortwave trough and sfc cyclogenesis over the lower MS/TN Valleys. Better rain chances will remain to our west but will continue to indicate isolated/slight chance pops across the far southern/southwestern zones with onset of In-situ Damming expected. Lows again in the lower 50s to upper 50s, coolest ne. && .LONG TERM /Friday through Tuesday/... As of 330 AM Wednesday... Friday through Saturday night: Shortwave energy is expected to quickly move eastwards from the plains on Thursday night and into our area by late Friday. This will result in chances for showers/rain increasing on Friday, with showers expected along with some storms on Friday night into Saturday with a Miller B type surface pattern (with a CAD boundary expected to develop/strengthen across our area). With a surface high pressure extending into the area from the north initially, before quickly moving offshore on Friday night, we should see an in-situ or hybrid damming event develop over our area. NWP models are showing a low or two tracking along the boundary on Saturday morning, with the associated cold front moving through the area as the last/primary surface low lifts off to the northeast by late Saturday morning early Saturday afternoon. Given the rather poor diurnal timing, the overall severe threat looks to be rather low (but not zero). However, if the timing of the frontal waves lag some, then we could see a increasing threat for some severe storms across our eastern and southern counties, as deep layer shear is expected to increase into the 30 to 40 kt range, increasing upper divergence, along with the aforementioned surface wave. However, the bigger story maybe the moderate to at times heavy rain on the cool side of the boundary (currently expected over the Piedmont/Northwest Piedmont. PW's are expected to increase to around 1.75" ahead of the system, so there will be ample moisture available. Average rainfall amounts are expected to range from around 0.75 to 1 inch across our southeast to possibly around 2 inches or more across the Northwest Piedmont. While we do not expect widespread issues from the heavy rain, we could see some minor flooding in urban areas or poor drainage locations. The main area of precip associated with this lead impulse is now expected to shift off to our northeast by mid Saturday afternoon. However, cyclonic flow aloft will linger across the area, with continued mostly cloudy skies and lingering chances of showers on Saturday night. Temps during this period will largely be driven by the developing/strengthening CAD, making temps quite tricky, with an expected warm sector across our southeast by Saturday morning. Will show temps ranging from the mid 60s nw to the mid to upper 70s se for highs on both Friday and Saturday, with lows showing a similar trend from the upper 50s to mid 60s. Sunday through Tuesday: Additional energy is expected to dive southward out of Canada helping to close off into a mid/upper level low over the mid atlantic region late weekend into early next week, which will result in continue chances for showers and possibly some storms depending on the placement of the mid/upper low for Sunday and Monday. However, the best chance for precip will be during the afternoon into the evening/more diurnally driven convection. Highs Sunday and Monday are expected to run near to generally slightly below normal. Highs Tuesday will return to more seasonable values as the mid/upper low is expected to lift off to the northeast. Lows temps are expected to be near normal. && .AVIATION /06Z Wednesday through Monday/... As of 740 AM Wednesday... 24-Hour TAF period: Rain will gradually taper off from west to east as the surface front and attendant offshore coastal low move farther out to sea. Despite the front moving south of the area, low-level moisture will remain in place across the area today, which will result in slow improvement through the day, with gradual lifting of IFR/LIFR ceilings to MVFR by the late afternoon. Additionally, with lingering low-level moisture in place, any weak shortwave impulses moving through the region could support light spotty rain/drizzle. Ceilings are expected to quickly fall/lower after sunset with IFR to LIFR conditions expected everywhere overnight/Thursday morning. Looking ahead: While mostly dry conditions are expected on Thursday, sub-VFR conditions will continue into Thursday, with ceilings once again lowering to IFR or LIFR Thursday night/Friday morning. A low pressure system tracking through the Southern states Friday through Saturday will result in widespread adverse aviation conditions in heavy rain and potentially a period of LLWS Friday night. Drier VFR conditions is expected to return on Sunday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...WSS/CBL SHORT TERM...CBL LONG TERM...BSD AVIATION...CBL  FXUS62 KRAH 150000 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 800 PM EDT Sun Oct 14 2018 .SYNOPSIS... Cool high pressure will extend across central NC today. A warm front will lift north through the area tonight ahead of a cold front that will approach the region from the northwest. This boundary will push through the area late Tuesday into Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 250 PM Sunday... Regional radar shows that the light shower activity from earlier today is quickly exiting to our east, in response to the causative short wave shear axis shifting eastward and offshore (as seen on current wv imagery). In it's wake, the CAD pattern that's been in place will persist the rest of this afternoon, until the parent high that's offshore the mid atlantic coast shifts farther east. After that happens this evening, low level flow will turn more toward the south with a slow increase low level dwpts. This increasing moisture will result in a period of low clouds and perhaps some fog to develop late tonight/Monday morning. Lows tonight a couple deg warmer than last night...55-60. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 250 PM Sunday... A cold front will approach the region Monday and cross central NC Monday night. Right now it appears that this front will move across mostly dry, lacking substantial moisture transport ahead of it. Nevertheless, will still carry slight chance PoPs to address any isolated showers that occur with its passage. Overall, look for partly cloudy skies and much warmer than today with central NC in the warm sector. Highs on Monday from the upper 70s NW to mid 80s SE. Lows Monday night in the 60s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 315 PM Sunday... A sub-tropical ridge is expected to be off the coast of Florida Tuesday with a long wave trough over eastern Canada. At the same time Tuesday an upper level low rotating over the southwestern United States will begin to get hung up underneath mid-level ridging. This block will help to allow for multiple cold air intrusions from Canada through the long term. For Tuesday itself, a cold front looks to stall near central North Carolina with a potential CAD situation developing. The latest run of the GFS actually shows a bit of isentropic upglide Tuesday morning with a slow breakout of ceilings for the triad during the day. The CMC, NAM, and ECMWF actually show the north winds and upglide continuing through Tuesday. As of now this appears a bit bullish considering the lack of a strong surface high pressure to the north and east. If the CAD does setup, temperatures will need to be lowered. The other consideration here is the chance for precipitation. Along the stalled boundary, both the GFS and ECMWF show multiple rounds of weak PVA. With the front sagging further south now, think the chance of thunder is minimal. Wednesday morning, a more potent round of PV will cross the area with a surface low forecast to form along the boundary. The CMC, ECMWF, and GFS all have the low forming, but the ECMWF and CMC have a better QPF footprint thanks to the tighter surface convergence. Wednesday afternoon another upper level disturbance will push southeast out of Canada driving the stalled front completely off the east coast. Along the front the chance of precipitation looks likely, as the saturated theta-e gradient is tight and PWATs are forecast to be 1.7" - 1.9". Behind this front much cooler air will filter in with PWATs plummeting towards 0.35" (as seen on the ECMWF and GFS). During the day Thursday, the upper level trough axis will pull east as surface high pressure moves overhead. 850 mb temperatures also fall to around 7 degrees C (tighter gradient on the ECMWF). This will support highs only in the lower to mid 60s. Friday into Saturday the high pressure will pull east with a warm front pulling north Saturday afternoon. The warmer temperatures Saturday will be short lived though as another rex block sets up over the Pacific Northwest which will allow for a potent upper level low to dive southeast out of Canada. The low will amplify the upper level trough axis allowing for a 1035 mb surface high pressure to dive southeast out of Canada. This cold front will cross the zones late Saturday into early Sunday. Behind the front much colder air will filter south. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... As of 800 PM Sunday... 24 Hour TAF period: A few sprinkles around this evening but a lot of the precipitation showing up on radar is not making it to the surface at this time. With a good amount of cloud cover over the area, ceilings are expected to lower overnight with short term models focusing on the western half of the forecast area for the lowest ceilings with IFR probable and some LIFR possible mainly after 9Z through 15z or so on Monday morning. For the eastern sites flight categories may be controlled more by visibility than ceilings with 1-3 miles favored by short term models at least at KFAY and KRWI again in the favored hours before and just after sunrise. KRDU may be a bit in between the lowest ceilings and visibilities and so might see them take the longest before going to sub-VFR conditions. Long Term: Remaining in the warm sector for Tuesday night with a front close by brings a good chance of sub-VFR conditions Monday night into Tuesday morning. The front crosses the area and potentially stalls out bringing more possible sub-VFR conditions Tuesday and Tuesday night before a likely return to VFR for the end of the week before another front approaches for Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...NP NEAR TERM...NP SHORT TERM...NP LONG TERM...Haines AVIATION...Ellis  FXUS62 KRAH 150601 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 200 AM EDT Mon Oct 15 2018 .SYNOPSIS... Cool high pressure centered off the mid-Atlantic coast will extend into the area tonight as a weak warm from lifts north. A cold front will approach the region from the northwest and push through the area late Tuesday into Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 1055 PM Sunday... Latest surface analysis shows surface high pressure centered off the mid-Atlantic coast with weak ridging into VA and northern NC. A weak warm front was noted across southern NC into northern SC. The evening proximity ROABs indicate a moistening air mass with the precipitable water value at GSO now 1.3 and 1.5 at KMHX. A fairly fast southwesterly to westerly flow aloft is noted at the mid and upper levels. The radar this evening has been more active than expected with a couple areas of very light rain skirting across the western and northern Piedmont. These areas of rain were associated with some disturbances in the fast flow aloft. In addition, some shallow isentropic lift across the Foothills will expand and shift northeast and easterly across the western Piedmont and northern Piedmont supporting a chance of rain. Skies range from cloudy across the western Piedmont to mostly clear across the Coastal Plain where some stratus and fog is apt develop overnight. Overnight lows will range in the mid 50s across the northwest Piedmont to around 60 in the southeast. -Blaes && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 250 PM Sunday... A cold front will approach the region Monday and cross central NC Monday night. Right now it appears that this front will move across mostly dry, lacking substantial moisture transport ahead of it. Nevertheless, will still carry slight chance PoPs to address any isolated showers that occur with its passage. Overall, look for partly cloudy skies and much warmer than today with central NC in the warm sector. Highs on Monday from the upper 70s NW to mid 80s SE. Lows Monday night in the 60s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 315 PM Sunday... A sub-tropical ridge is expected to be off the coast of Florida Tuesday with a long wave trough over eastern Canada. At the same time Tuesday an upper level low rotating over the southwestern United States will begin to get hung up underneath mid-level ridging. This block will help to allow for multiple cold air intrusions from Canada through the long term. For Tuesday itself, a cold front looks to stall near central North Carolina with a potential CAD situation developing. The latest run of the GFS actually shows a bit of isentropic upglide Tuesday morning with a slow breakout of ceilings for the triad during the day. The CMC, NAM, and ECMWF actually show the north winds and upglide continuing through Tuesday. As of now this appears a bit bullish considering the lack of a strong surface high pressure to the north and east. If the CAD does setup, temperatures will need to be lowered. The other consideration here is the chance for precipitation. Along the stalled boundary, both the GFS and ECMWF show multiple rounds of weak PVA. With the front sagging further south now, think the chance of thunder is minimal. Wednesday morning, a more potent round of PV will cross the area with a surface low forecast to form along the boundary. The CMC, ECMWF, and GFS all have the low forming, but the ECMWF and CMC have a better QPF footprint thanks to the tighter surface convergence. Wednesday afternoon another upper level disturbance will push southeast out of Canada driving the stalled front completely off the east coast. Along the front the chance of precipitation looks likely, as the saturated theta-e gradient is tight and PWATs are forecast to be 1.7" - 1.9". Behind this front much cooler air will filter in with PWATs plummeting towards 0.35" (as seen on the ECMWF and GFS). During the day Thursday, the upper level trough axis will pull east as surface high pressure moves overhead. 850 mb temperatures also fall to around 7 degrees C (tighter gradient on the ECMWF). This will support highs only in the lower to mid 60s. Friday into Saturday the high pressure will pull east with a warm front pulling north Saturday afternoon. The warmer temperatures Saturday will be short lived though as another rex block sets up over the Pacific Northwest which will allow for a potent upper level low to dive southeast out of Canada. The low will amplify the upper level trough axis allowing for a 1035 mb surface high pressure to dive southeast out of Canada. This cold front will cross the zones late Saturday into early Sunday. Behind the front much colder air will filter south. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 200 AM Monday... 24 Hour TAF period: Area of light rain/sprinkles and associated brief period of MVFR VSBY restrictions moving across the northern half of the forecast area will exit east in the next couple of hours. Wedge of weak high pressure over the area will give way to a warm front lifting north through the area late tonight/around daybreak. Continued moist upglide/isentropic lift is expected to yield lowering ceilings overnight, with short term models focusing on the western half of the forecast area for the lowest ceilings with IFR probable and some LIFR possible mainly after 9Z through 15z or so on Monday morning. For eastern TAF sites, there is some potential for patchy MVFR ceilings to develop as low level moisture increases ahead of the warm front. Daytime heating will lift and scatter out any sub-VFR ceilings from south to north through the mid to late morning hours, possibly delayed at KINT and KGSO until the early afternoon. Long Term: Sub-VFR conditions are expected to develop Monday night into Tuesday morning as a cold front moves into the area from the north. The front potentially stalls out across the area Tuesday and Tuesday night, prolonging sub-VFR conditions before a likely return to VFR on Wednesday when front finally settles south of the area. A cold front approaching the area from the NW will bring the next chance of sub-VFR conditions in showers late Friday night and into Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Blaes NEAR TERM...Blaes SHORT TERM...NP LONG TERM...Haines AVIATION...CBL  FXUS62 KRAH 081716 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 115 PM EDT Mon Apr 8 2019 .SYNOPSIS... The approach of an upper level disturbance, interacting with a moist and unstable atmosphere, will support the development of numerous showers and thunderstorms late this afternoon and this evening. A few of the storms may be severe. This storm system will allow for another round of showers and thunderstorms Tuesday before exiting the region Tuesday night. Dry and seasonal weather is expected for Wednesday and Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 1050 AM Monday... 12Z upper air analysis reveals a marginally moist atmosphere over central NC with a notable wly flow over the region. Aloft, a closed 500mb low was located in vicinity of the ARLATEX, with a lead perturbation/shear axis was noted between Birmingham and Nashville. The approach of this perturbation should cause the low-mid level flow to back to a southwesterly direction later this afternoon/evening. This backing will enhance the low level shear plus advect a warm moist air mass into central NC. This added moisture/instability coupled with the modest cool pool attendant with the perturbation should result in a slight-moderately unstable atmosphere by late afternoon-early evening. This should lead to the development of numerous showers and t-storms by late afternoon, continuing into the evening hours. Due to the presence of the available shear and instability, the potential will exists for a few severe storms to occur with the main severe weather threat being isolated damaging wind gusts and marginally large hail. Some caveats to this set-up will be: a.) low stratus deck this morning is inhibiting heating. If this low cloud deck is slow to dissipate, this will inhibit heating later this afternoon, resulting in lower than expected available instability; b.) 12Z GSO sounding depicts a rather thick layer of warm air between 850-700mb. Model projections suggest this layer becoming cooler late this afternoon with the approach of the mid level perturbation. If this fails to materialize, the presence of this warm layer will inhibit convection depth/development; c.) lack of a low level boundary to focus convection and enhance low level shear/helicity. All-in-all, near term forecast pretty much on target. Lingering low clouds late this morning will require some modest adjustment downward in the hourly temperatures to reflect the lack of sunshine. Some of the convective allowing models are depicting initial development over the southern Piedmont and Sandhills in proximity of a differential heating boundary. May need to adjust PoPs to place the initial focus farther south versus the NW Piedmont. Tonight, expect scattered to numerous showers and a few storms to persist well into the overnight as the lead perturbation lifts newd across the region. May see a downward trend in the convective coverage after 06Z. Otherwise, it will remain quite mild for this time of year with overnight temperatures in the low-mid 60s. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 435 AM Monday... The models are in better agreement regarding the timing of the mid- upr low now over ern TX, as it lifts newd and devolves into an open wave trough over the srn Appalachians by 12Z Tue, before migrating ewd to the sern US coast through early Wed. Related, 30-60 meter mid level height falls will overspread the Carolinas during the day and provide for large scale forcing for ascent Tue. Additionally, a preceding mid level dry slot punching newd into the ArkLaTex vicinity this morning, and an upstream EML plume evident in 00Z/8th RAOB data over wrn TX, will migrate newd and manifest as a plume of steep mid level lapse rates (around 7-7.5 C/km) over the Carolinas, on the poleward side of a 50 kt mid level speed max forecast to stream newd along the sern US coast during the same time. The former should yield moderate afternoon instability throughout cntl NC, as surface temperatures warm into the 70s and dewpoints remain in the lwr-mid 60s. At the surface, a polar front will extend from wrn PA/NY, swwd into the mid-South at 12Z Tue, then continue sewd to the sern US coast through early Wed. Meanwhile, an initially closed, 1005 mb surface low will track from cntl AL at 12Z Tue, newd across SC and srn-sern NC by 00Z Wed, possibly along a diabatically-generated/reinforced, Appalachian-lee mesoscale boundary, then offshore. The track of that wave will likely focus the most intense convection during the period over the ern Carolinas, where storm organization would be progressively more likely amidst the stronger flow aloft there -- including over the ern NC Sandhills and srn Coastal Plain-- where a mixed, multi-cell to supercell storm mode will be possible. Weaker deep layer shear will favor a multi-cell storm mode elsewhere, including scattered convection along the aforementioned polar front, and related nwrn bound of instability and deep convection, as it moves across the nwrn-nrn NC Piedmont through Tue evening. Two complicating factors in the above forecast will be: 1) a signal in model guidance for lingering early day convection over the sern half of cntl NC, and related diabatic influence and convective overturning of the otherwise steep mid level lapse rates, and 2) the degree of mid level dry air accompanying the foregoing steep mid level lapse rates, within the dry conveyor belt and modified EML plume, which may limit overall storm coverage. Such mesoscale influences will be better resolved and hopefully identified by tonight. It will otherwise turn drier, cooler, and less humid, as post- frontal surface dewpoint values decrease into the 40s to lwr 50s, with low temperatures in the 50s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 500 AM Monday... The models are in general agreement regarding the pattern at the surface and aloft and across the CONUS through the medium range, particularly regarding an initial, powerful cyclone forecast to track from the cntl Plains newd across the mid MS valley; upr Midwest; and Great Lakes Wed-Fri. Model spread increases relative to the amplification/development of a second powerful shortwave trough/closed low across the Rockies late in the week, with mostly amplitude differences downstream, as it tracks from the srn Plains to the lwr Great Lakes/nrn middle Atlantic states Sat-Mon. At the surface, continental Polar high pressure will initially build swd across the middle Atlantic states Wed-early Thu, then offshore, with related near average high temperatures and a few-several degrees below average low temperatures during that time. Between that surface high and the powerful cyclone tracking from the cntl US to the Great Lakes, the low level flow will veer to sly-swly, and strengthen, with related warm/moist advection that will peak across the Carolinas and middle Atlantic --with a related good to likely probability of showers and storms-- Fri-Fri night. Seasonably strong (1025-1030 mb), continental Polar high pressure expanding across the Great Lakes will help drive the related surface frontal zone swd across VA and NC Sat-Sat night, amidst subsident, shortwave ridging between the two deep troughs aloft, and on the nwrn rim of a strengthening sub-tropical ridge over the Caribbean/Bahamas. That surface ridge will likely provide for some degree of cold air damming across cntl NC on Sun, as isentropic upglide occurs atop the frontal zone/inversion and surface ridge. So while precipitation chances will be on the increase Sun, after a mainly dry and warm Sat, it seems at this time likely that much of cntl NC will remain in a cooler and more stable wedge air mass characterized by surface temperatures in the 60s on Sun, ranging to 70s over the srn part of the state/invof the frontal zone and higher probability of deep convection - some possibly strong-severe, given the pattern. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... As of 115 PM Monday... Expect variable aviation parameters across central NC as the weather pattern will be unsettled through Tuesday evening. Periods of showers and thunderstorms will cross the region late this afternoon, persisting into the first half of the overnight. Another round of showers and thunderstorms will threaten the region late Tuesday morning through Tuesday evening. In vicinity of the heavier showers and storms, anticipate MVFR/IFR ceilings and visibilities along with sfc wind gusts 30-40kts. In proximity of the stronger t-storms, some hail may be encountered. After 04Z Tuesday, areas of low stratus may develop with ceilings IFR/LIFR probable. These low ceilings expected to gradually lift Tuesday morning, followed by another round of showers and t-storms with MVFR/IFR parameters likely. Another round of low ceilings or areas of fog are possible late Tuesday evening prior to the arrival of a drier air mass which will overspread central NC from the west late Tuesday night into early Wednesday. VFR parameters appear likely Wednesday into Thursday. Another round of scattered convection with associated sub VFR parameters expected Friday into Friday evening. VFR parameters should return for Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS/Haines NEAR TERM...WSS SHORT TERM...MWS LONG TERM...MWS AVIATION...WSS  FXUS62 KRAH 090018 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 815 PM EDT Mon Apr 8 2019 .SYNOPSIS... The approach of an upper level disturbance, interacting with a moist and unstable atmosphere, will support the development of numerous showers and thunderstorms late this afternoon and this evening. A few of the storms may be severe. This storm system will allow for another round of showers and thunderstorms Tuesday before exiting the region Tuesday night. Dry and seasonal weather is expected for Wednesday and Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 400 PM Monday... 19Z meso analysis depicts a slightly unstable air mass over central NC with bulk shear strong enough to aid in organizing the cells into broken convective bands. The atmosphere ahead of the developing convective bands will continue to destabilize further as temperatures climb to or above 80 degrees. As the storms move into this favorable air mass, expect further intensification with a few storms becoming severe. A pocket of dry air in the 700-500mb layer will lend toward evaporation, enhancing downdrafts and leading to locally strong/damaging wind gusts. In addition, updrafts able to persist 20-30 minutes will have the potential to produce large hail. This hail threat currently appears highest over portions of the northern Piedmont. Through 21Z, expect to see the storms to eventually evolve into broken bands with a threat for damaging wind gusts. These band of convection will approach the highway corridor including the Triangle region in the 22Z-00Z time frame. After 00Z, expect the convective threat to increase along the I-95 corridor, though by this time, the near surface atmosphere will begin to stabilize with loss of heating. Expect scattered-numerous showers to persist into the overnight as a series of mid level perturbations move east across eastern GA and South Carolina. While overall coverage will be decent, intensity should be waning as the atmosphere stabilizes. Relatively mild night with overnight temperatures in the 60s. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 400 PM Monday... Tuesday, the upper level low currently crossing the lower MS Valley will open up and lift newd, in response to a s/w in the northern stream crossing the Great Lakes and into New England. This s/w will propel a sfc cold front toward central NC from the NW. The approach of the upper wave will increase upper diffluence over central NC. Meanwhile west-southwest 850mb flow will maintain a warm and moist air mass. The approach of the cold front will enhance low level convergence Tuesday afternoon through early Tuesday evening. GFS based instability parameters suggest MLCAPE values on the order of 1500-2000 J/kg by early Tuesday afternoon with bulk shear values of 40-50kts. These parameters suggest a better potential for storms with supercellular characteristics; though will caution that morning stratus/low clouds and scattered showers may temper the instability, leading to a less than robust atmosphere for scattered strong/severe convection. Still with better low level shear and a few sfc boundaries likely lurking in the region, could see a weak tornado or two in the afternoon, mainly south of highway 64. Atmosphere will be fairly uniform temperature wise thanks to the considerable cloudiness and scattered-numerous showers. Expect highs generally in the mid-upper 70s. The sfc cold front will drift sewd tuesday evening, bringing an end to the scattered convection NW-SE. NW flow behind the front will usher a stable drier air mass, leading to decreasing cloud cover overnight. Min temps lower 50s NW to the mid-upper 50s SE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 155 PM Monday... Overview: High amplitude ridging aloft will take over for the early part of the period before reverting back to large scale troughing by the weekend. By Wednesday morning, a backdoor cold front will continue its journey south through central NC, reinforced by strengthening surface high pressure descending briefly down the lee side of the Appalachians. Northerly/northeasterly flow will linger into Thursday before giving way to a dynamic WAA regime Thursday night into Friday just ahead of a Cold Front passage Friday night. High pressure returns briefly on saturday, with CAD like conditions strengthening Saturday night and Sunday as a southern stream disturbance begins to track northeastward into the mid Atlantic region Sunday and Monday. Wednesday and Thursday: High pressure settles in from the north Wednesday afternoon as a weak backdoor cold front descends southward. Weak northerly/northeasterly flow will help to limit afternoon high temperatures Wednesday and potentially into Thursday before southerly flow truly re-establishes in a strong WAA regime, allowing for some rapid warm-sector recovery east of the Appalachians. Highs will top out in the low to mid 70s Wednesday and Thursday with overnight lows dipping into the 40s. Friday/Friday Night: A shortwave will round the base of the northern Jet late Thursday into Friday spreading low to mid level vort maxes east through the Mid Atlantic. Best forcing looks to remain well north of our area, but with robust southerly flow helping to maximize the WAA regime in a mid-Spring type environment, it would be irresponsible to not at least carry mention of convection/thunder with the passage of the cold front, likely to spread WNW to ESE through the region Friday afternoon/evening. Rest of the period: Surface high pressure settles in from the northwest on Saturday before a CAD type setup commences on Sunday. Meanwhile, the southern stream becomes a bit more active, with broad scale troughing beginning the early stages of cyclogenesis over the MS River Delta late Saturday, transitioning energy northeastward into the Mid Atlantic by early next week. Will be keeping a close eye on the progression of this system as it could mark the next opportunity for widespread convection along with isolated Severe Weather as early as Sunday evening, highly dependent on the CAD dynamics in place. Check back for frequent updates here. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 815 PM Monday... Variable aviation parameters will persist across central NC as the weather pattern will be unsettled through Tuesday evening. Areas of of showers and thunderstorms will continue to track eastward across the region into the first half of the overnight, with some decrease in coverage after 08Z. Ceilings will trend lower after 06Z with widespread IFR/LIFR probable. Ceilings will gradually lift after 13Z, though MVFR ceilings will persist into Tuesday afternoon. Another round of showers and thunderstorms will threaten the region late Tuesday morning through Tuesday evening. In vicinity of the heavier showers and storms, anticipate MVFR/IFR ceilings and visibilities along with sfc wind gusts 30-40kts. In proximity of the stronger t-storms, some hail may be encountered. Another round of low ceilings or areas of fog are possible late Tuesday evening prior to the arrival of a drier air mass which will overspread central NC from the west late Tuesday night into early Wednesday. VFR parameters appear likely Wednesday into Thursday. Another round of scattered convection with associated sub VFR parameters expected Friday into Friday evening. VFR parameters should return for Saturday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS/Haines NEAR TERM...WSS SHORT TERM...WSS LONG TERM...JJM AVIATION...WSS