Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 220507 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 105 AM EDT TUE APR 22 2014 .SYNOPSIS...
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A WARM SOUTHWEST FLOW WILL BRING ABOVE NORMAL TEMPERATURES TODAY. A COLD FRONT WILL MOVE SLOWLY EASTWARD ACROSS OUR REGION THIS EVENING... THEN HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST WEDNESDAY THROUGH THURSDAY. ANOTHER COLD FRONT WILL APPROACH FROM THE WEST ON FRIDAY.
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&& .NEAR TERM /THROUGH TONIGHT/... AS OF 1002 PM MONDAY... A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT OVER NC THIS EVENING WILL WEAKEN AS IT DRIFTS EWD OVERNIGHT INTO TUESDAY MORNING. W-SW FLOW ALOFT IN THE WAKE OF THE DEPARTING RIDGE WILL ADVECT MOISTURE INTO OUR REGION...RESULTING IN PATCHES OF MID-HIGH LEVEL CLOUDINESS. SFC DEWPOINTS ARE AVERAGING SEVERAL DEGREES BELOW MOS GUIDANCE...MAINLY ACROSS THE NORTHWEST PIEDMONT....INDICATIVE OF HOW DRY THE AIR MASS IS UNDERNEATH THIS RIDGE AND HOW MODELS MAY BE WEAKENING ITS INFLUENCE OVER CENTRAL NC TOO QUICKLY PER SATELLITE IMAGERY AND TRENDS...BULK OF HIGH CLOUDS PATCHY WITH MORE SOLID OVERCAST WELL WEST OF CENTRAL NC. PER THIS TREND AND CHARACTER OF AIR MASS TO BE DRIER THAN PREDICTED...SKIES SHOULD BE NO WORSE THAN PARTLY CLOUDY THROUGH MOST OF THE NIGHT WITH JUST AN HOUR OR TWO OF MOSTLY CLOUDY SKIES POSSIBLE...MAINLY IN THE WEST. AIR MASS CONTINUES TO MODIFY AND WITH HIGH LEVEL MOISTURE ON THE INCREASE...EXPECT TEMPS OVERNIGHT TO AVERAGE 5-8 DEGREES WARMER THAN LAST NIGHT. EXPECT A DECENT RANGE BETWEEN URBAN AND RURAL AREAS WITH MIN TEMPS IN THE URBANIZED AREAS NEAR 50-LOWER 50S WHILE MORE SHELTERED LOCATIONS SHOULD SEE MIN TEMPS IN THE MID-UPPER 40S. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 1258 PM MONDAY... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE COLD FRONT AS IT PUSHES EAST OFF THE BLUE RIDGE EARLY AFTERNOON. THESE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS SHOULD PROGRESS ACROSS OUR REGION DURING PEAK HEATING. HOWEVER... WEAK CONVERGENCE ALONG THE FRONT... MEAN WESTERLY FLOW... LIMITED INSTABILITY (SURFACE DEW POINT RECOVERY ONLY IN THE LOWER TO MID 50S)... AND WEAK LAPSE RATES SUGGESTS THAT ONLY ISOLATED TO SCATTERED THUNDERSTORM OF THE GENERAL VARIETY. QPF OF LESS THAN 0.25 OF AN INCH IS EXPECTED. SW SURFACE WINDS SHOULD INCREASE AFTER SUNRISE WITH MIXING TO 10-20 MPH... WITH GUSTS TO 25-30 MPH IN THE AFTERNOON. THE WINDS WILL GRADUALLY BECOME WESTERLY AS THE FRONT SLIPS THROUGH DURING THE AFTERNOON. IN GENERAL... SKIES ARE EXPECTED TO BE PARTLY SUNNY... THEN BECOME MOSTLY CLOUDY. HIGHS IN THE MID TO UPPER 70S EXPECTED NW... TO AROUND 80-82 OR SO ELSEWHERE. THE SKIES WILL CLEAR TUESDAY NIGHT AS THE WINDS BECOME NW AND DIMINISH TO 10 MPH OR LESS LATE. TURNING COOLER WITH LOWS IN THE 40S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 245 PM MONDAY... WED-THU: DRY CONDITIONS WILL RULE IN THIS PERIOD DUE TO SYNOPTIC SUBSIDENCE ASSOC/W RISING HEIGHTS ATTENDANT AN UPPER LEVEL RIDGE BUILDING EAST FROM THE CENTRAL CONUS TO THE EASTERN SEABOARD. EXPECT TEMPS SEVERAL DEGREES BELOW NORMAL FOR THIS TIME OF YEAR...RANGING FROM THE UPPER 60S TO LOWER 70S ON WED AND LOWER TO MID 70S ON THU IN ASSOC/W SFC HIGH PRESSURE BUILDING INTO THE REGION FROM THE NORTH. FRI/FRI NIGHT: LOW-LEVEL MOISTURE ADVECTION WILL STRENGTHEN ACROSS THE CAROLINAS ON FRIDAY AS UPPER LEVEL RIDGING GIVES WAY TO BROAD CYCLONIC FLOW ALOFT OVER THE REGION. MARGINAL DIURNAL DESTABILIZATION (500-1000 J/KG MLCAPE) APPEARS LIKELY GIVEN RELATIVELY STEEP MID-LEVEL LAPSE RATES (~7 C/KM) ATOP AN INCREASINGLY MOIST BOUNDARY LAYER (CHARACTERIZED BY SFC DEWPOINTS AT OR SLIGHTLY ABOVE 60F). ALTHOUGH DEEP LAYER SHEAR WILL BE MORE THAN SUFFICIENT FOR ORGANIZED CONVECTION...DEAMPLIFYING SHORTWAVE ENERGY IS PROGGED TO TRACK ACROSS THE NORTHERN MID-ATLANTIC AND THE BEST FORCING /DCVA/ IS EXPECTED TO REMAIN FAR REMOVED FROM CENTRAL NC. AS A RESULT...UNCERTAINTY PERSISTS WITH REGARD TO WHETHER OR NOT DEEP CONVECTION (I.E. THUNDERSTORMS) WILL EVEN DEVELOP. WITH THE ABOVE IN MIND...WILL KEEP PRECIP CHANCES IN THE 30-40% RANGE. HIGHS FRI UPPER 70S TO LOWER 80S...LOWS FRI NIGHT MID/UPPER 50S. SAT-MON: UNCERTAINTY INCREASES DRAMATICALLY THIS WEEKEND INTO EARLY NEXT WEEK WITH REGARD TO THE EVOLUTION OF THE UPPER LEVEL PATTERN OVER THE EASTERN CONUS. THE 12Z ECMWF INDICATES A HIGHER THETA-E AIRMASS IN PLACE ACROSS THE CAROLINAS WITH AN OCCASIONAL CHANCE FOR CONVECTION...ESP SUN/MON...WHILE THE GFS INDICATES A COOLER/DRIER AIRMASS WITH LITTLE CHANCE FOR PRECIPITATION. AT THIS TIME WILL CONTINUE TO INDICATE A DRY FORECAST WITH NEAR NORMAL MAX/MIN TEMPERATURES. -VINCENT && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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AS OF 105 AM TUESDAY... VFR CONDITIONS ARE LIKELY TO DOMINATE AT ALL CENTRAL NC TAF SITES TODAY AND TONIGHT. A COLD FRONT APPROACHING SLOW FROM THE WNW TODAY WILL CROSS THE AREA THIS EVENING... CAUSING THE WARM SURFACE WINDS FROM THE SOUTHWEST TO SHIFT TO WEST THEN NORTHWEST LATE TONIGHT AS A SECONDARY FRONT DROPS SE THROUGH THE AREA. SCATTERED SHOWERS AND ISOLATED STORMS ARE EXPECTED ALONG AND AHEAD OF THIS FRONT... AFFECTING INT/GSO MAINLY 18Z-22Z TODAY... RDU 20Z-00Z... AND FAY/RWI MAINLY 21Z-01Z. CLOUD BASES ARE EXPECTED TO REMAIN VFR... AND THE DRY SUBCLOUD LAYER WILL LIMIT PRECIP AMOUNTS AND WILL KEEP VSBYS MOSTLY VFR... ALTHOUGH BRIEF MVFR VSBYS IN SHOWERS OR STORM REMAINS POSSIBLE. ENHANCED VARIABLE WIND GUSTS ARE POSSIBLE IN AND NEAR SHOWERS/STORMS. SCT CLOUDS BASED ABOVE 3500 FT ARE EXPECTED POST- FRONT TOWARD THE END OF THE TAF PERIOD. LOOKING BEYOND 06Z EARLY WEDNESDAY MORNING... HIGH CONFIDENCE IN VFR CONDITIONS IN CENTRAL NC THROUGH THU WITH HIGH PRESSURE BUILDING IN FROM THE NW. AN APPROACHING STORM SYSTEM FROM THE WEST WILL BRING A CHANCE FOR MVFR OR IFR CONDITIONS WITHIN SCATTERED SHOWERS/STORMS STARTING FRI MORNING. THIS SYSTEM WEAKENS LATE FRI AND HIGH PRESSURE SHOULD THEN RETURN FOR SAT... BRINGING A RETURN TO VFR CONDITIONS FRI NIGHT/SAT. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...WSS SHORT TERM...BADGETT LONG TERM...VINCENT AVIATION...HARTFIELD

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