Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 261948 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 248 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 NIGHT THROUGH FRIDAY NIGHT/... AS OF 244 PM WEDNESDAY... THURSDAY NIGHT...UPDATED SOON. FRIDAY AND FRIDAY NIGHT: SURFACE HIGH PRESSURE WILL BUILD IN FROM THE DEEP SOUTH ON FRIDAY AS THE UPPER LEVEL TROUGH MOVES OFF OF THE COAST. FOR THE FIRST PART OF THE DAY...CENTRAL NC WILL REMAIN ON THE EAST SIDE OF THE HIGH...IN WEAK NORTHERLY FLOW BUT BY LATE AFTERNOON THE HIGH WILL MOVE DIRECTLY OVERHEAD...CALMING ANY REMAINING WIND. CLOUD COVER LEFT OVER FROM THE DEPARTING SYSTEM WILL FILTER OUT TO THE NORTHEAST. THUS EXPECT LOWEST TEMPS IN THE NE AND HIGHEST IN THE SW. COOLEST DAY OF THE WEEK WITH HIGHS IN THE MID 40S TO NEAR 50 DEGREES. FRIDAY NIGHT WILL SEE TEMPERATURES DROP INTO THE MID TO UPPER 20S WITH FEW CLOUDS AND CALM WINDS. -ELLIS && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 245 PM WEDNESDAY... SATURDAY THROUGH MONDAY NIGHT: THE FIRST PART OF THE LONG TERM WILL FEATURE A SIGNIFICANT WARMING TREND AS SURFACE HIGH PRESSURE MOVES EAST OF THE AREA SETTING UP RETURN FLOW OVER CENTRAL NC. THIS WILL BE THE MAIN DRIVER AS UPPER LEVEL FLOW REMAINS VERY ZONAL. ALTHOUGH BOTH THE GFS AND THE ECMWF AGREE THAT IT WILL BE WARMER...THE QUESTION REMAINS HOW MUCH? WITH FEW TO SCATTERED CLOUDS OVER THE AREA...RISING THICKNESSES AND WARM AIR ADVECTION THROUGH SOUTHWESTERLY FLOW...CANT SEE HOW TEMPERATURES WONT RISE SIGNIFICANTLY. THEREFORE HAVE GONE TO THE HIGH SIDE OF GUIDANCE WHICH IN THIS CASE IS MORE IN LINE WITH THE LONG RANGE ECMWF NUMBERS FOR MAX TEMPS THROUGH MONDAY. SPECIFICALLY MID TO UPPER 50S SATURDAY...MID TO UPPER 60S SUNDAY...AND UPPER 60S TO LOWER 70S MONDAY. LOWS WILL ALSO WARM THROUGH THE WEEKEND BUT MORE MODESTLY...UPPER 30S INCREASING TO MID 40S SUNDAY NIGHT BEFORE FALLING SLIGHTLY BACK INTO THE LOWER 40S ON TUESDAY AHEAD OF A COLD FRONT DRAPED TO OUR NORTHWEST. TUESDAY THROUGH WEDNESDAY: THE LAST PART OF THE LONG TERM INTRODUCES A FAIR AMOUNT OF UNCERTAINTY IN THE HANDLING OF THE AFOREMENTIONED COLD FRONT AS THE PARENT LOW IS IS QUICKLY HAULED AWAY TO THE NORTHEAST BY THE NORTHERN STREAM JET...LEAVING A WEAKLY DEFINED FRONTAL ZONE JUST TO THE NORTHWEST OF THE CWA. ANY PRECIPITATION ASSOCIATED WITH TEH FRONT SHOULD HOLD OFF UNTIL TUESDAY MORNING WHEN A FAIRLY STRONG 1040 MB HIGH PRESSURE SYSTEM MOVES THROUGH QUEBEC. THIS LOCATION IS FURTHER NORTH THAN THE PREVIOUS MODEL RUNS AND IS NOT QUITE AS IDEAL FOR A CLASSICAL/HYBRID COLD AIR DAMMING EVENT AS IT WAS YESTERDAY. STILL THINK SOME FORM OF A WEAK CAD IS POSSIBLE AND THUS KEEPING HIGHS ON TUESDAY FAIRLY LOW AS WE SHOULD BE OVERCAST WITH NORTHEASTERLY WINDS. MAX TEMPS IN THE LOW TO UPPER 50S BUT STILL COULD BE LOWER IN THE TRIAD IF WEDGE DEVELOPS. THIS HIGH WILL NOT REMAIN IN PLACE FOR VERY LONG AS IT IS QUICKLY MOVES OUT TO SEA BY A DEVELOPING LOW OVER NORTHERN ONTARIO AND A DEEPENING UPPER LEVEL TROUGH OVER THE MIDWEST. THIS WILL SET UP A SLIGHTLY WARMER DAY ON WEDNESDAY IN THE WARM AIR ADVECTION REGIME AHEAD OF THE FRONT AS LONG AS THE WEDGE DISSIPATES. MID 50S TO MID 60S NW TO SE. PRECIP CHANCES AND AMOUNTS STILL FAIRLY UNCERTAIN AT THIS POINT BUT WILL CARRY SLIGHT CHANCE POPS TUESDAY AND WEDNESDAY. LOWS DURING THIS TIME IN THE UPPER 30S TO LOWER 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...HARTFIELD/ELLIS LONG TERM...ELLIS AVIATION...HARTFIELD

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