Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 242314 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 714 PM EDT FRI OCT 24 2014 .SYNOPSIS...AN UPPER LEVEL DISTURBANCE APPROACHING THE MOUNTAINS FROM THE NORTHWEST WILL TRACK INTO WESTERN PORTIONS OF THE CAROLINAS TONIGHT...THEN MOVE OFFSHORE THE SOUTHEAST COAST ON SATURDAY. AN UPPER LEVEL RIDGE WILL BUILD EASTWARD FROM THE CENTRAL PLAINS TO THE EAST COAST SATURDAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 245 PM FRIDAY... AN AMPLIFYING SHORTWAVE TROUGH DIGGING SOUTHEAST THROUGH THE TENNESSEE VALLEY THIS AFTERNOON WILL TRACK THROUGH THE CAROLINAS TONIGHT AND PROGRESS OFFSHORE THE SOUTHEAST COAST BY SUNRISE SATURDAY. RAOB DATA INDICATES A PROFOUNDLY DRY/STABLE AIR MASS IN PLACE ACROSS THE REGION...A RESIDUAL EFFECT OF STRONG SUBSIDENCE THAT OCCURRED ON THURSDAY. WITH LARGE STATIC STABILITY... DPVA ASSOC/W THE UPPER LEVEL WAVE APPROACHING THE REGION WILL BE CONFINED ALMOST ENTIRELY TO THE UPPER LEVELS (H3-H5)...AS EVIDENCED BY RAPID COOLING/MOISTENING IN THE H3-H5 LAYER FROM 00Z TO 12Z TODAY ON THE GSO RAOB. WITH THE ABOVE IN MIND...EXPECT PARTLY TO OCCASIONALLY MOSTLY CLOUDY SKIES ASSOCIATED WITH CIRRUS (CEILINGS 18-25 KFT) ATTENDANT THE AMPLIFYING SHORTWAVE PROGRESSING INTO THE REGION. GIVEN THE ALTITUDE AT WHICH THESE CEILINGS ARE PRESENT...IN ADDITION TO VARYING DEGREES OF OPACITY...ANTICIPATE LITTLE OVERALL IMPACT ON TEMPERATURES WITH HIGHS SIMILAR THOUGH SLIGHTLY WARMER THAN YESTERDAY AND LOWS SIMILAR TO THIS MORNING...BOTH NEAR `AVERAGE` FOR THIS TIME OF YEAR. GENERALLY 40-45. -VINCENT && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 1230 PM FRIDAY... THE SHORTWAVE TROUGH DIGGING SOUTHEAST ACROSS THE CAROLINAS TONIGHT WILL EXIT OFFSHORE THE SOUTHEAST COAST SATURDAY MORNING. MODEST SUBSIDENCE AND H5 HEIGHT RISES IN THE WAKE OF THE SHORTWAVE WILL REINFORCE THE DRY/STABLE ATMOSPHERE IN PLACE ACROSS THE REGION... MAINTAINING CLEAR SKIES WITH ABSOLUTELY NO CHANCE FOR PRECIPITATION. STRENGTHENING WESTERLY LOW-LEVEL FLOW WILL RESULT IN WEAK WARM ADVECTION DURING THE DAY. AS A RESULT...EXPECT HIGH TEMPS ON SAT A FEW DEGREES WARMER THAN TODAY...AROUND 72-75F. NW FLOW ALOFT WILL STRENGTHEN ACROSS THE REGION SAT NIGHT AS AN AMPLIFYING UPPER LEVEL LOW DIGS RAPIDLY SOUTHEAST FROM CANADA INTO NEW ENGLAND BY 12Z SUN. THE MSLP GRADIENT WILL TIGHTEN OVER THE MID-ATLANTIC AND CAROLINAS SAT NIGHT...MAINTAINING A WESTERLY BREEZE AT 5-10 KT. AS A RESULT... FULL RADIATIONAL COOLING WILL NOT BE ACHIEVED...AND LOWS WILL MOST LIKELY BOTTOM OUT IN THE LOW/MID 50S IN THE ABSENCE OF A 1-3 HR PERIOD OF CALM WINDS. -VINCENT && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 302 PM FRIDAY... WARM AND DRY CONDITIONS CAN BE EXPECTED SUNDAY THROUGH WEDNESDAY... THEN A BACKDOOR FRONT SHOULD BRING CLOUDS AND COOLER CONDITIONS WEDNESDAY NIGHT AND THURSDAY. A STRONGER COLD FRONT SHOULD PUSH SE THROUGH THE REGION THURSDAY NIGHT BRINGING COOLER AIR FRIDAY. UPPER RIDGING WILL BUILD FROM THE PLAINS EASTWARD TO THE ATLANTIC SEABOARD SUNDAY THROUGH TUESDAY. RISING HEIGHTS ALOFT WITH A MEAN WESTERLY FLOW MEAN DRYING AND WARMING FOR CENTRAL NC. HIGHS SHOULD PUSH OR SURPASS 80 OVER THE SANDHILLS AND POSSIBLY THE EASTERN AND SOUTHERN PIEDMONT INTO THE COASTAL PLAIN MONDAY... THEN SHOULD MAX OUT TUESDAY IN THE LOWER TO POSSIBLY SOME MID 80S. THESE READINGS SHOULD BE CLOSE... BUT NOT QUITE AT THE DAILY RECORDS FOR OCTOBER 28... WHICH ARE 86... 86... AND 87 AT GSO... RDU... AND FAY (ALL RECORDED IN 1919. SLIGHT COOLING WILL BEGIN MAINLY BECAUSE OF THE CLOUDINESS EXPECTED TO INCREASE OUT AHEAD OF A COLD FRONT WEDNESDAY AFTERNOON. HIGHS SHOULD STILL REACH WELL INTO THE 70S AND POSSIBLY 80 AGAIN IN THE SOUTH CENTRAL AND SE ZONES WEDNESDAY WITH THE SW FLOW AT 10-15 MPH. THE WIND IS EXPECTED TO SHIFT TO THE NNE WEDNESDAY NIGHT INTO THURSDAY WITH THE PASSAGE OF THE "BACKDOOR" FRONT. CAUTION IS ADVISED ON THE EXTENT SOUTHWARD THAT THIS FRONT WILL MAKE IT GIVEN THE MODEL FORECASTS OF A FAIRLY "WEAK` SURFACE HIGH PRESSURE TO PUSH THE FRONT SOUTHWARD... DOWN THE EASTERN SEABOARD. CURRENT PROJECTIONS INDICATE THE FRONT MAY STALL WEST TO EAST ACROSS NC... AND THIS MAY BE TOO FAR SOUTH IF THE CURRENT MODELS VERIFY WITH THE LACK OF PUSH OF CAA WITH THE 1016-1017 MB HIGH PRESSURE BEHIND THE FRONT. REGARDLESS... THE LACK OF DEEP MOISTURE SHOULD PREVENT SIGNIFICANT RAIN ALONG THIS FRONT... AND IT SHOULD RETREAT BACK NORTHWARD QUICKLY THURSDAY AFTERNOON OR NIGHT AS A NEW STORM TRACKS NEAR THE GREAT LAKES. THIS MEAN STORM TRACK WELL TO OUR NORTH WILL DRIVE ANOTHER STRONGER COLD FRONT SE ACROSS THE APPALACHIANS AND NC LATE THURSDAY NIGHT AND EARLY FRIDAY. HOWEVER... ONLY SCATTERED SHOWERS ARE CURRENTLY ANTICIPATED WITH THE FRONT WITH THE MAIN STORM TRACK WELL TO OUR WEST AND NORTH. A PUSH OF COOLER AND DRIER AIR SHOULD FOLLOW THE FRONT... BUT TEMPS SHOULD REMAIN NEAR NORMAL EVEN BEHIND THIS FRONT AS THE COLD CANADIAN AIR WILL NOT GET PUSHED TO OUR LATITUDE YET. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
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AS OF 714 PM FRIDAY... 24-HOUR TAF PERIOD: HIGH CONFIDENCE THAT VFR CONDITIONS WILL DOMINATE THE TAF PERIOD. THERE WILL LIKELY BE A PERIOD OF SCATTERED TO BROKEN HIGH CLOUDS EARLY TONIGHT AS A SHORTWAVE TRAVERSES THE AREA...BUT SKIES SHOULD CLEAR OUT BY MORNING. WINDS WILL BE CALM TO LIGHT AND VARIABLE OVERNIGHT...INCREASING TO 4-8 KTS DURING THE DAY SATURDAY. -KC LOOKING AHEAD: VFR CONDITIONS WILL PERSIST THROUGH EARLY TO MID NEXT WEEK IN ASSOCIATION WITH A PERSISTENTLY BENIGN SYNOPTIC PATTERN. -VINCENT
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...PWB AVIATION...KC/VINCENT

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