Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 261722 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1220 PM EST WED NOV 26 2014 .SYNOPSIS...STRONG SURFACE LOW PRESSURE OVER THE CENTRAL NC COAST THIS MORNING WILL TRACK NORTHWARD ALONG THE MIDATLANTIC COAST THROUGH THIS AFTERNOON. A STRONG UPPER LEVEL DISTURBANCE WILL QUICKLY CROSS THE REGION LATE TONIGHT THROUGH EARLY THURSDAY. HIGH PRESSURE WILL BUILD OVER THE CAROLINAS FRIDAY THROUGH THE REST OF THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 955 AM WEDNESDAY... REST OF TODAY: FORECAST IS LARGELY ON TRACK... ALTHOUGH WE`LL SEE A SLIGHTLY EARLIER TAPERING DOWN OF THE PRECIP. LATEST SURFACE MAP SHOWS THE LOW JUST SE OF NEW BERN... MORE INLAND THAN MODELS WERE DEPICTING YESTERDAY. THE NARROW RELATIVE DRY SLOT JUST WEST OF THE SURFACE LOW HAS SOMEWHAT LIMITED RAINFALL SINCE LAST NIGHT OVER PORTIONS OF THE COASTAL PLAIN. THE LION`S SHARE OF THE CONVECTION HAS HELD ALONG AND JUST EAST OF THE OLD FRONTAL ZONE OVER COASTAL NC... WHILE THE MORE STEADY MODERATE BANDED PRECIP JUST W/NW OF THE 850 MB LOW -- SUPPORTED BY STRONG UPPER DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A 150-200 KT JET -- HAS LED TO HIGHER RAIN TOTALS OVER THE PIEDMONT OVER THE LAST SEVERAL HOURS. MINOR MID LEVEL DRYING AND A NORTHWARD SHIFT OF THE BETTER UPPER DIVERGENCE HAS LED TO A DECREASE IN PRECIP RATES OVER PORTIONS OF THE SRN HALF OF THE CWA IN THE LAST HOUR OR SO. THE MID LEVEL VORTICITY MAX RIDING AROUND THE BASE OF THE MEAN CENTRAL/ERN CONUS TROUGH IS CLEARLY SEEN ON RADAR AND WATER VAPOR IMAGERY TRACKING NE THROUGH THE SRN APPALACHIANS. BASED ON THIS FEATURE`S TIMING AND LATEST HRRR GUIDANCE... WE SHOULD SEE RAIN TAPERING OFF IN THE SW CWA BY 11 AM- NOON... AND ACROSS MOST OF THE WRN AND SRN CWA BEFORE 3 PM. WE MAY SEE ANOTHER STREAK OF HEAVIER PRECIP AHEAD OF THE VORTICITY MAX AS A SMALL JET STREAK ANALYZED OVER AL/NRN GA TRACKS SLIGHTLY EAST OF DUE NORTH. OTHERWISE... WILL TAPER DOWN POPS ACCORDING TO THESE TIME FRAMES THROUGH THIS AFTERNOON. ADDITIONAL QPF SHOULD BE MOST SUBSTANTIAL OVER THE PIEDMONT... WITH ONLY LIGHT ADDITIONAL AMOUNTS OVER THE EAST/SOUTHEAST (SANDHILLS AND COASTAL PLAIN). WILL MAINTAIN GUSTY WINDS FROM THE NW THROUGH NNE GUSTING UP TO 20-25 KTS... BUT AS THE SURFACE LOW DRAWS STEADILY NORTHWARD... WINDS SHOULD SHIFT TO UNIFORM NW AND BEGIN TO SUBSIDE BY MID AFTERNOON. MOST PLACES HAVE ALREADY SEEN THEIR HIGHS TODAY... SO EXPECT TEMPS TO WAVER JUST A FEW DEGREES... STAYING MAINLY IN THE 40S. -GIH EARLIER DISCUSSION FROM 320 AM: TODAY...THE APPROACH OF A SUBSTANTIAL S/W LIFTING NE OUT OF THE DEEP SOUTH EARLY THIS MORNING (REFER TO LATEST WATER VAPOR IMAGERY) WILL CAUSE A SURFACE LOW PRESSURE TO STRENGTHEN AND MOVE ALONG THE NC COAST THIS MORNING...THEN LIFT TO THE NE THIS AFTERNOON. ALOFT...A STEADY STREAM OF MOISTURE OFF BOTH THE GULF AND PACIFIC IS BEING PULLED NORTHWARD VIA A STRONG JET EXTENDING ALONG OR JUST WEST THE SPINE OF APPALACHIANS (190-200KTS PER 00Z UPPER AIR ANALYSIS). THE LIFT PROVIDED ALOFT BY THE APPROACH OF THE S/W AND THE RIGHT ENTRANCE REGION OF THE JET...COUPLED WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE DEVELOPING SFC LOW WILL CAUSE WIDESPREAD RAIN ACROSS CENTRAL NC THIS MORNING. OBSERVED RAINFALL RATES HAVE BEEN ABOUT A TENTH OF AN INCH PER HOUR THOUGH WHERE POCKETS OF MODERATE RAIN HAVE OCCURRED...RAINFALL RATES AROUND A QUARTER OF AN INCH HAVE BEEN RECORDED. BASED ON THE EXPECTED TIMING/EXTENT OF RAIN...MOST LOCATIONS WILL LIKELY SEE A SOLID HALF TO ONE INCH OF RAIN WITH POCKETS OF AROUND 1.5 INCHES LIKELY. WILL LIKELY SEE TWO AXES OF MAXIMUM PRECIPITATION...ONE OVER THE PIEDMONT IN ASSOCIATION WITH THE UPPER LEVEL JET WHILE THE OTHER WILL BE CLOSER TO COAST ASSOCIATED WITH THE SURFACE WAVE. THUS MAY SEE A RELATIVE MINIMUM IN PRECIP INTENSITY IN VICINITY OF THE I-95 CORRIDOR (GOOD NEWS FOR HOLIDAY TRAVELERS). SFC WINDS WILL BE BLUSTERY THIS MORNING IN RESPONSE TO THE STRENGTHENING LOW PRESSURE ALONG THE COAST. WIND GUSTS AROUND 30 MPH HIGHLY PROBABLE OVER OUR EASTERN COUNTIES...AND ESPECIALLY ALONG THE I-95 CORRIDOR. AS THE SURFACE LOW PULLS TO THE NORTH-NE THIS AFTERNOON...WILL SEE THE RAIN TAPER OFF FROM THE SW...POSSIBLY STARTING IN THE SOUTHERN PIEDMONT BY MID-LATE MORNING...PROGRESSING INTO THE TRIAD AND TRIANGLE AREAS AS WELL AS FAYETTEVILLE BY EARLY-MID AFTERNOON. MAX TEMPS TODAY WILL BE FAIRLY COMPARABLE TO CURRENT TEMPS AS NLY FLOW BEHIND THE EXITING WAVE WILL FILTER COOLER AIR INTO OUR REGION LATER THIS MORNING THROUGH THE AFTERNOON. TEMP PROFILES ALOFT ACROSS THE NW PIEDMONT SUGGEST SOME MOISTURE/LIFT INTO THE ICE NUCLEATION REGION ALTER THIS MORNING. DURING TIMES OF ENHANCED PRECIP INTENSITY...COULD SEE SOME WET SNOW MIXED IN THE RAIN BUT THIS OCCURRENCE EXPECTED TO BE FEW AND FAR BETWEEN. TONIGHT...WHILE ATLANTIC SYSTEM WILL BEING QUICKLY EXITING OUR REGION...A FAST MOVING S/W (CURRENTLY SEEN ON WATER VAPOR IMAGERY EXITING THE CENTRAL PLAINS INTO THE MID MS VALLEY) WILL CROSS APPROACH AND CROSS OUR REGION LATE TONIGHT INTO EARLY THURSDAY MORNING. THIS SYSTEM EXPECTED TO STRENGTHEN AS IT GETS INTO THE BOTTOM OF THE L/W TROUGH. THIS UPPER DISTURBANCE INTERACTING WITH AVAILABLE RESIDUAL MOISTURE WILL TRIGGER A FEW SHOWERS ACROSS OUR NORTHERN COUNTIES OVERNIGHT THROUGH THE MORNING HOURS OF THURSDAY. NOT SEEING ENOUGH MOISTURE NOR LIFT INTO THE ICE NUCLEATION REGION TO WARRANT MENTION OF SNOW SHOWERS AT THIS TIME SO JUST EXPECTING A CHILLY RAIN. WHILE PRECIP AMOUNTS EXPECTED TO BE LIGHT...DO BELIEVE PRECIP EXTENT WILL BE ENOUGH TO WARRANT A HIGH CHANCE/LIKELY POP OVER TEH FAR NORTH-NW LATE TONIGHT THROUGH EARLY THURSDAY. MIN TEMPS IN THE MID 30S TO LOWER 40S. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 320 AM WEDNESDAY... THURSDAY...MID LEVEL S/W WILL EXIT THE REGION LATE THURSDAY MORNING WITH DWINDLING PRECIP CHANCES ACROSS THE NORTH AFTER 15Z. WLY FLOW BEHIND THE S/W WILL BE BREEZY WITH GUSTS 20-25 MPH PROBABLE. THE DOWNSLOPE COMPONENT TO THE LOW LEVEL WIND WILL AID TO DISSIPATE CLOUD COVERAGE IN THE AFTERNOON AND ALSO WARM TEMPS UP A BIT. MAX TEMPS THURSDAY AFTERNOON UPPER 40S TO AROUND 50 NW TO MID 50S SE. -WSS THE L/W TROUGH AXIS WILL PUSH TO THE EAST OF CENTRAL NC LATE WEEK... WHILE HIGH PRESSURE AT THE SURFACE BUILDS INTO THE AREA. THIS WILL YIELD A RETURN TO QUITE WEATHER WITH BELOW NORMAL TEMPERATURES. HOWEVER... A FEW WEAK DISTURBANCES ALOFT IN THE WEST-NORTHWESTERLY MID LEVEL FLOW MAY BRING SOME MID TO HIGH CLOUDS TO THE AREA BY FRIDAY NIGHT... PROBABLY PARTLY CLOUDY AT WORST THOUGH. LOWS FRIDAY MORNING... DRIVEN BY CAA... ARE EXPECTED TO GENERALLY BE IN THE MID TO UPPER 20S AS LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PLUMMET TO AROUND 1280 METERS ACROSS THE NORTHWEST PIEDMONT. SIMILAR LOW LEVEL THICKNESS VALUES HAVE YIELDED LOW TEMPS GENERALLY IN THE 20-27 DEGREE RANGE IN THE PAST AT KGSO. THUS... HAVE TRENDED LOW TEMPS TOWARD THE COOL SIDE OF GUIDANCE... WHICH IS THE MAV. AFTERNOON LOW LEVEL THICKNESS VALUES ARE ONLY EXPECTED TO RECOVER TO AROUND 1300 METERS FOR FRIDAY AFTERNOON. THUS... WITH LOW LEVEL THICKNESS VALUES SOME 40 METERS BELOW NORMAL FOR THIS TIME OF YEAR... WILL LOWER HIGH TEMPS SOME... A BIT BELOW STATISTICAL GUIDANCE. EXPECT HIGH TEMPS ON FRIDAY WILL GENERALLY BE IN THE MID TO UPPER 40S. HIGH PRESSURE WILL SETTLE OVER THE REGION BY FRIDAY EVENING INTO FRIDAY NIGHT. THIS WILL YIELD LIGHT AND VARIABLE TO CALM WINDS. EVEN WITH SOME MID TO HIGH CLOUDS CROSSING THE AREA FROM TIME TO TIME... STILL THINK WE WILL SEE LOWS TEMPS FALL INTO THE MID TO UPPER 20S AGAIN. -BSD && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 255 AM WEDNESDAY... HIGH PRESSURE WILL SHIFT TO THE SOUTH AND EAST OF CENTRAL NC THIS WEEKEND ALLOWING FOR A WARMING TREND. HIGH TEMPS ARE EXPECTED TO BE IN THE 50S FOR SATURDAY AND 60S FOR SUNDAY. MID LEVEL RIDGING IS FORECAST TO BUILD NORTHWARD DURING THIS TIME FRAME AND NUDGE INTO OUR AREA. HOWEVER... AS A NORTHERN STEAM TROUGH IS FORECAST TO TRACK NEAR THE U.S./CANADIAN (EAST COAST THAT IS) BORDER DURING THIS TIME FRAME A TRAILING COLD FRONT WILL DROP SOUTHWARD AND POSSIBLY INTO CENTRAL NC BY EARLY NEXT WEEK. WITH THE MID LEVEL FLOW ONLY WSW IN ADVANCE OF THIS FEATURE (THANKS TO THE MID LEVEL RIDGE TO THE S/SE OF THE AREA) THIS SYSTEM WILL NOT HAVE THAT MUCH MOISTURE TO WORK WITH. COMBINE THAT WITH THE FROT DROPPING GENERALLY SOUTHWARD AND INTO THE AREA... WILL KEEP PRECIP CHANCES ONLY IN THE SLIGHT CHANCE CATEGORY. HIGH TEMPS EARLY NEXT WEEK WILL DEPEND ON THE TIMING OF THE FRONT. FOR NOW... WILL KEEP MONDAY MILD IN THE 60S TO AROUND 70... WITH HIGHS ON TUESDAY IN THE 50S TO NEAR 60 SOUTH. HOWEVER... SOME OF THE RAW MODEL GUIDANCES SHOWS HIGH TEMPS STRUGGLING TO GET OUT OF THE 40S ON TUESDAY NOW... AS THE SURFACE HIGH BUILDING INTO THE AREA FROM THE NORTH IS FORECAST TO BE QUITE STRONG... AROUND 1040-1045 MB. LOWS DURING THE PERIOD ARE GENERALLY EXPECTED TO BE IN THE 40S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 1220 PM WEDNESDAY... EXPECTED AVIATION CONDITIONS: POOR THROUGH THIS AFTERNOON... BECOME FAIR TO GOOD THIS EVENING... BRIEFLY POOR AT NORTHERN SITES LATE TONIGHT THROUGH THU MORNING... THEN GOOD BY EARLY THU AFTERNOON. PRIMARY AVIATION CONCERNS: LOW CIGS THROUGH THIS AFTERNOON AND AGAIN LATER TONIGHT. CURRENT MVFR CIGS AT CENTRAL NC TERMINALS (EXCEPT BRIEFLY IFR ESPECIALLY AT GSO/RDU) WILL PERSIST FOR ANOTHER FEW HOURS. AREAS OF RAIN CONTINUE BUT THE HEAVIEST RAIN HAS DEPARTED... THUS VSBYS ARE NOW MOSTLY VFR. CIGS WILL IMPROVE TO VFR FROM SW TO NE BETWEEN 19Z AND 23Z AS A POTENT UPPER LEVEL DISTURBANCE NOW OVER THE FAR WRN PIEDMONT OF NC TRACKS QUICKLY TO THE NE AND MOVES AWAY FROM NC LATER TODAY. BRIEF MAINLY VFR CONDITIONS ARE EXPECTED THIS EVENING... THEN ANOTHER DISTURBANCE AND SURFACE LOW WILL QUICKLY CROSS THE REGION... TRACKING ROUGHLY ALONG THE NC/VA BORDER... FROM LATE TONIGHT THROUGH THU MORNING. IFR/LIFR CIGS ARE EXPECTED AT GSO/INT AFTER MIDNIGHT TONIGHT UNTIL LATE MORNING THU... AND MVFR CIGS ARE POSSIBLE AT RDU/RWI THU MORNING THROUGH THE END OF THE TAF VALID PERIOD. BRISK WINDS MAINLY FROM THE NORTH WILL BE OF CONCERN AT ALL SITES THROUGH 21Z TONIGHT... THEN WINDS WILL BE LIGHT THIS EVENING THROUGH TONIGHT. WEST WINDS UP TO 8-12 KTS POSSIBLE THU MORNING INTO AFTERNOON. LOOKING BEYOND 18Z THU... VFR CONDITIONS ARE EXPECTED TO LAST THROUGH MON... AS HIGH PRESSURE BUILDS IN FROM THE WEST OVER THE WEEKEND BEFORE SHIFTING TO OUR EAST ON MONDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS/HARTFIELD NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS/BSD LONG TERM...BSD AVIATION...HARTFIELD

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