Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 200815 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 315 AM EST THU NOV 20 2014 .SYNOPSIS...A DRY COLD FRONT WILL MOVE THROUGH THE AREA ON THURSDAY AFTERNOON BEFORE HIGH PRESSURE RETURNS FOR THE END OF THE WEEK. A LOW PRESSURE SYSTEM WILL APPROACH THE AREA ON SUNDAY...CAUSING MORE UNSETTLED CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 220 AM THURSDAY... THE UPPER LEVEL TROUGH OVER THE EASTERN CONUS REMAINS IN PLACE THIS MORNING AS DOES HE SURFACE HIGH OVER THE GULF COAST THAT HAS PROVIDED SOME SOUTHWESTERLY FLOW OVER CENTRAL NC AND SOME RELIEF TO YESTERDAYS RECORD COLD TEMPERATURES. THIS COMBINED WITH A SHORTWAVE THAT HAS LEFT SOME MID TO UPPER LEVEL CLOUDS OVER THE CWA HAS HELPED KEEP TEMPERATURES UP SO FAR THIS MORNING AS WE ARE STILL IN THE MID 30S...BUT LOCATIONS IN THE SOUTHWEST WHERE THE CLOUD COVER HAS BEGUN TO CLEAR OUT HAVE DROPPED INTO THE LOWER 30S WITH SOME UPPER 20S SHOWING UP ACROSS NORTHERN SOUTH CAROLINA. CLOUDS WILL CONTINUE TO MOVE OUT TO THE NORTHEAST AND TEMPERATURES WILL BEGIN TO DROP AS THAT HAPPENS. THEREFORE STILL EXPECTING LOWS THIS MORNING IN THE MID TO UPPER 20S. THIS AFTERNOON A DRY COLD FRONT IS PROGGED TO CROSS THE AREA GRADUALLY FROM NORTH TO SOUTH. WITH THIS MAY COME SOME UPPER LEVEL CLOUDS BUT NOT MUCH ELSE. THE FRONT WILL CAUSE THE WINDS TO SHIFT FROM SOUTHWESTERLY TO A MORE WEST NORTHWESTERLY DIRECTION AND ONCE AGAIN BRING A COLDER AIRMASS INTO THE AREA BY LATER TONIGHT. WIND GUSTS TO 20 KTS ARE POSSIBLE THIS AFTERNOON. HIGH TEMPERATURES WILL BE NEAR 50 IN THE NW AND UPPER 50S TO NEAR 60 IN THS SOUTH WHERE THE DRY ADIABATIC METHOD...THICKNESS VALUES AND A LATER ARRIVAL OF COLD AIR ADVECTION OF THE FRONT SHOULD GIVE MORE TIME FOR TEMPERATURES TO RISE A LITTLE MORE IN THE SOUTHEAST. WILL LEAN TO THE HIGH SIDE OF GUIDANCE IN THIS AREA. AFTER FRONTAL PASSAGE SKIES WILL CLEAR OUT AND COLD AIR ADVECTION WILL BEGIN ONCE AGAIN AS THICKNESSES DROP BACK INTO THE 1290-1310 METER RANGE BY 12Z FRIDAY. THIS WILL SUPPORT LOWS IN THE UPPER 20S TO LOW 30S FROM NORTH TO SOUTH. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
AS OF 315 AM THURSDAY... FRIDAY AND FRIDAY NIGHT: SURFACE HIGH PRESSURE WILL MOVE IN FROM THE OHIO VALLEY AND GRADUALLY RELAX THE COLD AIR ADVECTION OVER THE AREA. IN ADDITION...UPPER LEVEL FLOW OVER THE CAROLINAS WILL BECOME MUCH MORE ZONAL. STILL WILL BE A COOLER DAY THAN THURSDAY WITH HIGHS IN THE MID 40S TO LOW 50S. A BIT OF AN ANOMALOUS TEMPERATURE DISTRIBUTION AS THE LOWEST THICKNESS VALUES...AND THUS COLDEST TEMPERATURES... WILL BE IN THE NORTHEAST. THE HIGH WILL SETTLE IN AND KEEP THINGS CLEAR AS WELL AS RELAX THE AFTERNOON WIND GUSTS THAT HAVE BEEN PREVALENT OVER THE LAST SEVERAL DAYS. THICKNESS VALUES FAVOR MINIMUM TEMPERATURES IN THE MID 20S TO LOW 30S BUT NEAR OPTIMAL RADIATIONAL COOLING CONDITIONS WILL KEEP US ON THE LOWER SIDE OF THAT RANGE...MID TO UPPER 20S WITH SOME LOWER 20S POSSIBLE IN THE USUAL COLD SPOTS. -ELLIS SATURDAY AND SATURDAY NIGHT: SOUTHERN STREAM TROUGH OVER THE SOUTHWEST US WILL ADVANCE EASTWARD THROUGH THE SOUTHERN PLAINS ON SATURDAY AND THEN INTO THE LOWER/CENTRAL MS VALLEY SATURDAY NIGHT. STRONG 1035MB SURFACE HIGH CENTERED OVER NC TO START THE DAY WILL QUICKLY SHIFT OFFSHORE WITH AN EAST-WEST DRY AIR RIDGE LINGERING UNDERNEATH WEAK/MINOR HEIGHT RISES ALOFT. MODEL ARE IN GOOD AGREEMENT THAT PRECIP WILL BE DELAYED UNTIL AFTER DAYBREAK SUNDAY...THOUGH STRENGTHENING S/SE LOW-LEVEL ATLANTIC MARITIME FEED SATURDAY EVENING/NIGHT WILL RESULT IN RAPID MOISTURE RECOVERY AND WIDESPREAD LOW CLOUDS/STRATUS. DRY ADIABATIC MIXING TO 950-970MB WILL SUPPORT HIGHS OF 50 TO 55. NOT NEARLY AS COLD SATURDAY NIGHT COMPARED TO FRIDAY NIGHT/SATURDAY MORNING OWING TO THICKENING CLOUD COVER AND RETURN FLOW. LOWS IN THE LOWER 30S TO UPPER 30S.
-- End Changed Discussion --
&& .LONG TERM /SUNDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 315 AM THURSDAY... SUNDAY AND SUNDAY NIGHT: SOUTHERN STREAM TROUGH AND ATTENDANT DEEPENING SURFACE LOW OVER THE CENTRAL MS VALLEY SUNDAY MORNING WILL LIFT NORTHWARD INTO THE UPPER GREAT LAKES ON SUNDAY...WHERE IT WILL REMAIN NEARLY STATIONARY THROUGH TUESDAY. WHILE THE BEST TROUGH DYNAMICS REMAIN WEST OF THE MOUNTAINS...STRONG/DEEP GULF MOISTURE TRANSPORT WITHIN THE TRANSIENT EASTWARD PROPAGATING WARM CONVEYOR BELT WILL RESULT IN A WET SUNDAY- SUNDAY EVENING PERIOD ACROSS THE CAROLINAS. LOOK FOR POPS TO QUICKLY RAMP UP SW TO NE SUNDAY MORNING-MIDDAY WITH A SURGE OF ISENTROPIC LIFT/WAA ATTENDANT TO A NORTHWARD LIFTING WARM FRONT. EXPECT WIDESPREAD RAINFALL AMOUNTS OF A 0.50" TO AN 1.0". IMPRESSIVE LOW- LEVEL KINEMATIC WIND FIELDS FUELED BY A 60-65KT LOW-LEVEL JET COUPLED WITH ENHANCED NEAR SURFACE HELICITY/SHEAR ALONG A NORTHWARD RETREATING WEDGE FRONT LOOKS TO HAVE LIMITED BUOYANCY TO WORK WITH MODELS SUGGESTING VERY WEAK INSTABILITY OF 200-300 J/KG OF ACROSS THE SOUTHEAST FORECAST AREA...LIMITED BY WIDESPREAD CLOUDS AND RAIN. WILL CONTINUE TO MONITOR BUT SEVERE THREAT LOOKS LOW AND CONFINED TO EAST-SOUTHEAST COASTAL AREAS. IN-SITU DAMMING FROM THE OFFSHORE HIGH AND WIDESPREAD RAIN WILL RESULT IN A SLOW RISE IN TEMPERATURES DURING THE DAY ON SUNDAY...UNTIL THE WARM FRONT LIFTS NORTH THROUGH THE AREA DURING THE LATE AFTERNOON AND THROUGH THE EVENING ACROSS THE NW PIEDMONT. DAYTIME HIGHS WILL OCCUR AFTER SUNSET IN MANY LOCATIONS WITH TEMPERATURES HOLDING STEADY OR QUITE POSSIBLY WARM OVERNIGHT. HIGHS IN THE MID-UPPER 50S NW TO UPPER 60S SE. MONDAY THROUGH WEDNESDAY: MID-LEVEL DRY SLOT WILL RESULT IN A LULL IN RAIN CHANCES ON MONDAY...WITH RAIN CHANCES RETURNING MONDAY NIGHT- TUESDAY WITH THE APPROACH OF THE FRONT. WITH CENTRAL NC IN THE WARM SECTOR...TEMPERATURES WILL SOAR INTO THE UPPER 60S TO LOWER/MID 70S ON MONDAY. TEMPERATURES WILL FALL BACK TO NEAR NORMAL ON TUESDAY WITH THE ARRIVAL OF COOLER AIR AND BELOW NORMAL TEMPS DELAYED UNTIL THE PASSAGE OF THE UPPER TROUGH WEDNESDAY-WEDNESDAY NIGHT.
-- End Changed Discussion --
&& .AVIATION /06Z THURSDAY THROUGH SUNDAY/... AS OF 645 AM THURSDAY... 24 HOUR TAF PERIOD: VERY HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE TAF PERIOD. SOME MID AND HIGH LEVEL CLOUDS DRAPED ACROSS THE CWA THIS MORNING AS A SHORTWAVE MOVES THROUGH THE AREA. THESE WILL GRADUALLY DECREASE DURING THE MORNING HOURS BUT THEN A NEW SET OF MID TO UPPER LEVEL CLOUDS WILL ROTATE THROUGH THE NORTHERN SITES LATER THIS AFTERNOON WITH A DRY COLD FRONT. WIND GUSTS ARE AGAIN POSSIBLE DURING THE AFTERNOON UP TO 20 KTS IN MOST LOCATIONS...A LITTLE LESS IN THE SOUTH. AS THE DRY FRONT COMES THROUGH WINDS WILL GO FROM A PRIMARILY SOUTHWESTERLY DIRECTION TO A MORE WEST NORTHWESTERLY DIRECTION. SKIES WILL EVENTUALLY CLEAR LATER THIS EVENING. LONG TERM: NO THREAT TO AVIATION CONDITIONS UNTIL SUNDAY WHEN A WARM FRONT IS EXPECTED TO ROTATE UP THROUGH THE AREA AND CONDITIONS COULD REMAIN BELOW VFR UNTIL THE SUBSEQUENT COLD FRONTAL PASSAGE...EITHER MONDAY NIGHT OR EARLY TUESDAY. && .CLIMATE... RECORD LOW: GSO RDUFAY SAT 11/22 - 13 IN 1914 21 IN 2008 20 IN 2000 && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...ELLIS NEAR TERM...ELLIS SHORT TERM...ELLIS/CBL LONG TERM...CBL AVIATION...ELLIS CLIMATE...RAH

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.