Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 220001 CCA AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 801 PM EDT MON APR 21 2014 .SYNOPSIS...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. && .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/... 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 /00Z TUESDAY THROUGH SATURDAY/...
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AS OF 800 PM MONDAY... MOSTLY VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE CURRENT TAF PERIOD. LIGHT AND VARIABLE WINDS OVERNIGHT WILL GIVE WAY TO WESTERLY/SOUTHWESTERLY WINDS ON TUESDAY...WITH SOME GUSTS INTO THE UPPER TEENS. A COLD FRONT WILL APPROACH AND CROSS THE REGION TUESDAY AFTERNOON. AHEAD OF THE FRONT...MID/HIGH CLOUDS WILL INCREASE OVERNIGHT AND THEN THICKEN AND LOWER THROUGHOUT THE DAY ON TUESDAY...BUT OVERALL SHOULD STAY IN THE VFR RANGE. THE EXCEPTION MAY BE A PERIOD OF MVFR CIGS/VSBYS...ASSOCIATED WITH A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS...GENERALLY BETWEEN 18-00Z. WINDS WILL SHIFT TO A MORE NORTHWESTERLY DIRECTION BEHIND THE FRONT...BUT THIS MAY OCCUR JUST BEYOND THE CURRENT TAF PERIOD (AFTER 00Z/23)... MAYBE SLIGHTLY BEFORE IN THE TRIAD. OUTLOOK...VFR CONDITIONS WILL THEN PREVAIL THROUGH AT LEAST THURSDAY AS HIGH PRESSURE DOMINATES. THE NEXT CHANCE FOR ADVERSE AVIATION CONDITIONS WILL BE THURSDAY NIGHT/FRIDAY MORNING AS THE HIGH SHIFTS OFFSHORE AHEAD OF AN APPROACHING FRONT AND MOIST RETURN FLOW SETS UP OVER THE REGION. THE FRONT IS PROGGED TO CROSS THE REGION FRIDAY INTO FRIDAY NIGHT...BRINGING WITH IT ANOTHER CHANCE OF SHOWERS AND/OR STORMS AND ASSOCIATED ADVERSE AVIATION CONDITIONS.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT SHORT TERM...BADGETT LONG TERM...VINCENT AVIATION...KRD

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