Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 211930 CCA AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 245 PM EDT MON APR 21 2014 .SYNOPSIS...
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HIGH PRESSURE WILL EXTEND OVER THE REGION TONIGHT THEN SHIFT OFFSHORE TUESDAY MORNING. A COLD FRONT WILL MOVE ACROSS THE STATE TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD BACK IN BEHIND THE FRONT FOR WEDNESDAY THROUGH THURSDAY.
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&& .NEAR TERM /THROUGH TONIGHT/... AS OF 1258 PM MONDAY... A RIDGE OF HIGH PRESSURE WILL BRING CLEAR SKIES AND LIGHT WINDS THIS EVENING. SOME MID AND HIGH LEVEL MOISTURE WILL BEGIN TO INCREASE LATER TONIGHT OUT AHEAD OF THE APPROACHING MID/UPPER TROUGH FROM THE WEST. SKIES SHOULD BECOME PARTLY CLOUDY OVERNIGHT IN THE WEST. UNDER THE RIDGE... WINDS WILL BE LIGHT. LOWS 45-50 (COOLEST NE RURAL AREAS). && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
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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.
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&& .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 /18Z MONDAY THROUGH FRIDAY/... AS OF 1258 PM MONDAY... VFR CONDITIONS THIS AFTERNOON THROUGH TONIGHT AND TUESDAY MORNING. A COLD FRONT WILL PUSH INTO THE REGION TUESDAY AFTERNOON... THEN SHIFT EAST TUESDAY EVENING. GENERALLY VFR CIGS EXPECTED EXCEPT FOR A PERIOD OF MVFR CIGS/VSBYS BETWEEN 18Z/22Z KINT/KGSO... AND BETWEEN 20Z/23Z KRDU/KRWI/KFAY... WITH A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. THE CHANCE OF THUNDERSTORMS IS ONLY 15-20 PERCENT... SO WILL OMIT FROM TAF. RATHER GUSTY SW WINDS WILL BECOME W AT 12- 20KT WITH GUSTS TO 25KT BETWEEN 17Z-23Z... THEN NW 10-15KT. A RETURN TO VFR CONDITIONS ARE EXPECTED TUESDAY NIGHT WITH DIMINISHING NNW BREEZES FROM 10KT-15KT TO LIGHT OVERNIGHT. VFR CONDITIONS EXPECTED WED-FRI. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT SHORT TERM...BADGETT LONG TERM...VINCENT AVIATION...BADGETT

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