Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 260811 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 410 AM EDT SUN APR 26 2015 .SYNOPSIS...
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A STALLED FRONT WILL REMAIN JUST SOUTH OF CENTRAL NC THIS MORNING AS AN UPPER LEVEL DISTURBANCE CROSSES THE AREA. A COLD FRONT WILL SLIP SOUTH THROUGH CENTRAL NC THIS AFTERNOON AND EVENING.
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&& .NEAR TERM /THROUGH TONIGHT/... AS OF 245 AM SUNDAY... NEXT FEW HOURS... REGIONAL OBS ANALYSIS SHOWS THE STALLED FRONTAL ZONE JUST SOUTH OF THE NC/SC BORDER...WITH ALL OF CENTRAL NC WELL WITHIN THE STABLE CAD AIRMASS. TO OUR WEST...AND MCV AND ASSOCIATED BAND OF CONVECTION HAS BEEN WEAKENING AS IT CROSSES THE MOUNTAINS AND APPROACHES THE STABLE AIR...BUT THE SPC MESOANALYSIS SHOWS SOME RECOVERY OF MUCAPE ACROSS THE SOUTHERN PIEDMONT...AS MUCH AS 500- 1000 J/KG...WHICH SHOULD CONTINUE AHEAD OF THE UPPER DISTURBANCE... WITH THE INSTABILITY EVENTUALLY BEING SHUNTED EAST ACROSS THE SOUTHERN COASTAL PLAIN. EFFECTIVE BULK SHEAR REMAINS STRONG ACROSS THE SOUTH...UP TO 40KT. WHILE THE INVERSION IS LIKELY TOO STRONG FOR STRONG WIND GUSTS...SOME REINVIGORATION OF THE APPROACHING CONVECTION...ALONG WITH A FEW DISCRETE CELLS ALONG THE FRONT...MAY PROVIDE A THREAT OF HAIL THROUGH 12Z...MAINLY ACROSS THE SOUTHERN PIEDMONT/SANDHILLS/SOUTHERN COASTAL PLAIN. TODAY... ONCE THIS CONVECTION MOVES EAST...MODELS SHOW LITTLE IN THE WAY OF ADDITIONAL SHOWERS THROUGH EARLY AFTERNOON. AND 850MB FRONT TO OUR NORTH WILL PUSH SOUTH THROUGH CWA THIS AFTERNOON...WHICH WILL HELP TO WEAK THE CAD INVERSION AND ALLOW SOME BREAKS IN CLOUD COVER AS DRIER AIR ALSO FILTERS IN FROM THE NORTH. SOME AREAS OF DRIZZLE MAY LINGER THIS MORNING...BUT OTHERWISE ONLY SEE A NEED FOR A SLIGHT CHANCE POPS THAT ENDS FROM NORTH TO SOUTH TODAY. HIGHS ARE A LITTLE TRICKY WITH THE POTENTIAL FOR BREAK IN THE CLOUDS BOTH ACROSS THE NORTH AND SOUTH...THOUGH MORE SO IN THE SOUTH. A BLEND OF THE MAV/MET LOOKS REASONABLE...WITH HIGHS AROUND 70 IN THE SOUTH AND MID 50S IN THE NORTH. TONIGHT... NORTHERLY FLOW WILL CONTINUE TO FUNNEL THE DRIER STABLE AIR MASS INTO OUR REGION...WITH SKIES CLEARING OVERNIGHT. LOWS IN THE LOWER 40S NORTH TO UPPER 40S SOUTH. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 335 AM SUNDAY... ANOTHER SHORTWAVE ROUNDING THE UPPER LOW OVER NOVA SCOTIA WILL CROSS NC ON MONDAY...BUT WILL ENCOUNTER A MUCH DRIER AND MORE STABLE AIRMASS...WITH PW AROUND ON HALF INCH AND A STRONG MID-LEVEL INVERSION. MODELS SUGGEST THE NORTHERN COASTAL PLAIN WOULD BE THE MOST FAVORED AREA FOR AN ISOLATED SHOWER OR SPRINKLE MONDAY AFTERNOON WITH A SHALLOW LAYER OF SATURATION NEAR 850MB. OTHERWISE...SKIES WILL BE MOSTLY SUNNY WITH AN NORTHWEST WIND AND THICKNESSES AROUND 30M BELOW NORMAL...YIELDING HIGHS ABOUT 1 DEGREES BELOW NORMAL IN THE 65-70 RANGE. LOWS MONDAY NIGHT IN THE MID 40S. && .LONG TERM /TUESDAY THROUGH FRIDAY/...
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AS OF 405 AM SUNDAY... THE MODELS ARE COMING INTO BETTER AGREEMENT REGARDING THE EASTWARD- SHEARING/DEAMPLIFICATION OF AN INITIALLY CLOSED LOW OVER THE SW US AND CONCURRENT A AMPLIFICATION OF A NORTHERN STREAM SHORTWAVE TROUGH FROM NW CANADA TO THE MID-MS VALLEY...ALL ON THE WESTERN PERIPHERY OF A DEEP VORTEX OFF THE NEW ENGLAND COAST. MODEL SPREAD INCREASES THROUGH THE END OF THE WEEK...HOWEVER...AS THE MODELS CONTINUE TO HAVE A DIFFICULT TIME RESOLVING THE AMPLIFICATION OF ADDITIONAL NORTHERN STREAM SHORTWAVE ENERGY INTO AN EASTERN CONUS TROUGH...AND HOW THIS ENERGY ULTIMATELY INTERACTS WITH THE LEAD WAVES. THE MODELS ARE IN SIMILARLY GOOD AGREEMENT AT THE SURFACE REGARDING THE DEVELOPMENT OF SURFACE LOW ALONG THE GULF COAST TO NEAR SAVANNAH GA BY 00Z THU...WITH INCREASING MODEL SPREAD/DECREASING FORECAST CONFIDENCE REGARDING THE TRACK AND TIMING OF THE LOW INTO THE WESTERN ATLANTIC. WILL FOLLOW WPC PREFERENCE TOWARD A SLOWER SOLUTION ON THE WESTERN EDGE OF THE MODEL SPREAD...WITH A SUSPICION THAT THE TRAILING NORTHERN STREAM WILL HELP DRAW THE CYCLONE WEST/CLOSER TO THE COAST AS IT LIFTS UP THE MIDDLE ATLANTIC COAST THROUGH THU. THE SENSIBLE WEATHER AFFECTS WILL BE A WARM AND DRY TUE...WITH TEMPERATURES IN THE MIDDLE 60S TO AROUND 70 DEGREES...FOLLOWED BY RAIN DEVELOPING/SPREADING NORTHEAST INTO CENTRAL NC LATE TUE NIGHT OVER THE SOUTHERN PIEDMONT AND ACROSS THE REMAINDER OF THE CWFA THROUGH THE DAY WED. EVEN PRIOR TO THE ONSET OF RAIN WED...MID LEVEL OVERCAST SHOULD CAUSE TEMPERATURES TO REMAIN BELOW GUIDANCE - IN THE UPPER 50S TO LOWER 60S...WARMEST NE; AND EVEN THOSE TEMPERATURES MAY ULTIMATELY PROVE A CATEGORY TOO WARM IF THE OVERCAST AND RAIN INDEED MATERIALIZE AS EXPECTED. RAIN WOULD THEN TAPER OFF FROM WEST TO EAST WED NIGHT-THU...AND YIELD TO DRIER AND WARMER CONDITIONS FRI- SAT...WITH TEMPERATURES RETURNING TO NEAR AVERAGE LEVELS IN THE MIDDLE 70S TO AROUND 80 DEGREES BY SAT.
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&& .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 200 AM SUNDAY... WIDESPREAD IFR AND LIFR CONDITIONS WILL CONTINUE OVERNIGHT WITH A STALLED FRONT SOUTH OF CENTRAL NC AND AN IN-SITU COLD AIR DAMMING AIRMASS OVER THE AREA. MEANWHILE...AN UPPER LEVEL DISTURBANCE AND BAND OF CONVECTION CURRENTLY CROSSING THE MOUNTAINS WILL CONTINUE EAST AND BRING A CHANCE OF A SHOWER OR ISOLATED STORM THROUGH 12Z. A FEW STRONG STORMS REMAIN POSSIBLE...MAINLY FROM KRCZ TO KFAY...BUT STRONG WIND GUSTS ARE NOT EXPECTED DUE TO THE STRONG INVERSION NEAR THE SURFACE. THESE SHOWERS AND STORMS WILL MOVE EAST OF THE EAST OF THE AREA AFTER 12Z...WITH JUST SOME LINGERING AREAS OF RAIN/DRIZZLE THAT WILL SHIFT SOUTH DURING THE AFTER AS SOME DRIER AIR FILTERS INTO THE AREA FROM THE NORTH. CEILINGS WILL REMAIN SUB-VFR THROUGH THE AFTERNOON HOURS BUT SHOULD BEGIN TO LIFT AND SCATTER FROM NORTH TO SOUTH BY LATE AFTERNOON AND EARLY EVENING. CONFIDENCE IN THE TIMING OF VFR OF CONDITIONS IS LOW...BUT VFR CONDITIONS ARE POSSIBLE BY THE END OF THE CURRENT TAF PERIOD. OUTLOOK...IMPROVING CONDITIONS WILL CONTINUE MONDAY MORNING...WITH VFR CONDITIONS EXPECTED MONDAY AND TUESDAY. A LOW PRESSURE SYSTEM APPROACHING FROM THE SW WILL BRING THE NEXT CHANCE FOR SUB VFR CONDITIONS TO CENTRAL NC WEDNESDAY INTO THURSDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...22 NEAR TERM...22 SHORT TERM...22 LONG TERM...RAH AVIATION...22

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