Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 201744 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1244 PM 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 1000 AM THURSDAY... THE UPPER LEVEL LOW THAT HAS BEEN SITTING OVER EASTERN CANADA REMAINS IN PLACE THIS MORNING. THE 12Z UPPER AIR ANALYSES SHOW THE TROUGH ALONG AND WEST OF THE APPALACHIANS AND THE H25 JET OVER NORTHERN NC AND SOUTHERN VA. THE LOW IS EXPECTED TO MOVE OFF TO THE ENE THROUGH TONIGHT...WITH THE TROUGH AND ASSOCIATED COLD FRONT PUSHING INTO THE REGION. THE FRONTAL PASSAGE WILL BE DRY...WITH JUST SOME SCATTERED LOW TO MID CLOUDS AHEAD OF IT...AND BRING WITH IT A REINFORCING SHOT OF COLD AIR AS SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST. EXPECT THE SOUTHWESTERLY WINDS TO SHIFT MORE NW BEHIND THE FRONT THEN MORE NORTHERLY TONIGHT. WINDS WILL AGAIN BE SUSTAINED AROUND 10 KTS...GUSTING TO 15-20 KTS THIS AFTERNOON. HIGHS SHOULD RANGE FROM AROUND 50 DEGREES NW TO UPPER 50S ACROSS THE SOUTH. IF THE FRONT IS A BIT SLOWER AND THE CLOUDS HOLD OFF...COULD SEE HIGHS A COUPLE/FEW DEGREES HIGHER. OVERNIGHT LOWS WILL GENERALLY RANGE FROM THE MID 20S NW TO LOW 30S SOUTH...BUT AGAIN IS DEPENDENT ON THE TIMING AND SOUTHWARD PROGRESS OF THE FRONT OVERNIGHT. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... 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. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... 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. && .AVIATION /18Z THURSDAY THROUGH MONDAY/...
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AS OF 1244 PM THURSDAY... 24-HOUR TAF PERIOD: VERY HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE TAF PERIOD. CLEAR SKIES MAY GIVE WAY TO SOME MID LEVEL CLOUDS THIS AFT/EVE...MAINLY ACROSS THE NORTH...AS A DRY COLD FRONT MOVES INTO THE AREA. EXPECT CLEAR SKIES OVERNIGHT. SOUTHWEST WINDS WILL CONTINUE TO GUST IN THE 15-20 KT RANGE THIS AFTERNOON...WITH GUSTS ABATING AFTER SUNSET. AS THE COLD FRONT MOVES INTO AND THROUGH THE AREA...WINDS WILL VEER FROM SOUTHWESTERLY TO NORTHERLY THROUGH THE OVERNIGHT HOURS. LOOKING AHEAD: THE NEXT THREAT TO AVIATION CONDITIONS WILL BE WITH A LOW PRESSURE SYSTEM APPROACHING AND MOVING THROUGH THE AREA SUNDAY INTO MONDAY...YIELDING INCREASING CLOUD COVER AND PRECIPITATION CHANCES. CONDITIONS COULD REMAIN BELOW VFR UNTIL THE COLD FRONTAL PASSAGE...EITHER MONDAY NIGHT OR EARLY TUESDAY. WINDS WILL LIKELY BECOME GUSTY AS THE FRONT APPROACHES AND MOVES THROUGH THE REGION.
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&& .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...KC SHORT TERM...ELLIS/CBL LONG TERM...CBL AVIATION...KC CLIMATE...RAH

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