Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 071051 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 650 AM EDT MON JUL 7 2014 .SYNOPSIS...A WEAK SURFACE TROUGH WILL LINGER OVER THE PIEDMONT THROUGH TUESDAY. A SLOW MOVING COLD FRONT WILL SETTLE INTO THE CAROLINAS FROM THE NORTHWEST ON LATE WEDNESDAY INTO THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 253 AM MONDAY... TODAY AND TONIGHT...WLY FLOW ALOFT AND A LEE SIDE SURFACE TROUGH OVER THE WESTERN PIEDMONT WILL RESULT IN WARM AND DRY CONDITIONS TODAY. THE ONE MINOR EXCEPTION WILL BE SOUTHERN SAMPSON COUNTY...WHERE A SHOWER OR THUNDERSTORM MAY ENCROACH UPON THE HARRELLS/IVANHOE REGION LATE TODAY IN ASSOCIATION WITH SEABREEZE CONVECTION THAT DEVELOPS. THIS SEABREEZE CONVECTION MAY BE A LITTLE ENHANCED BY A NEWD MOVING UPPER LEVEL SYSTEM THAT WILL PARALLEL THE SOUTHERN NC COAST THIS AFTERNOON. LOW LEVEL THICKNESSES THIS AFTERNOON REACH INTO THE 1420S...10-15M WARMER THAN SUNDAY. THIS YIELDS HIGH TEMPS THIS AFTERNOON AROUND 90 NW TO THE LOWER 90S ELSEWHERE. TONIGHT...CLEAR TO PARTLY CLOUDY SKIES WILL DOMINATE AS AIR MASS REMAINS RELATIVELY DRY...ESPECIALLY IN THE MID-UPPER LEVELS. MIN TEMPS SHOULD BE SEVERAL DEGREES WARMER COMPARED TO CURRENT NIGHT DUE TO AIR MASS MODIFICATION. MIN TEMPS UPPER 60S-LOWER 70S. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 253 AM MONDAY... LEESIDE TROUGH SHARPENS IN RESPONSE TO A S/W ALOFT MOVING E-SE ACROSS THE OH VALLEY/LOWER GREAT LAKES. THIS STRENGTHENING OF THE SURFACE TROUGH WILL RESULT IN AN UPTICK IN SW SURFACE WINDS WITH SUSTAINED SPEEDS 9-12KTS EXPECTED WITH GUSTS AROUND 20 KTS. THIS STOUT SW FLOW IN CONJUNCTION WITH PARTLY-MOSTLY SUNNY SKIES WILL AID TO BOOST AFTERNOON TEMPS INTO THE LOW-MID 90S. A WEAK DISTURBANCE ALOFT MAY INTERACT WITH AVAILABLE (BUT STILL RATHER LIMITED) MOISTURE TO SUPPORT AN ISOLATED THUNDERSTORM DURING THE MID-LATE AFTERNOON HOURS ACROSS THE NW PIEDMONT. LOW LEVEL MOISTURE WILL CONTINUE TO GRADUALLY INCREASE LEADING TO A LITTLE MORE HUMID CONDITIONS...ESPECIALLY BY TUESDAY NIGHT. MIN TEMPS TUESDAY NIGHT 69- 74. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 310 AM MONDAY... WEDNESDAY THROUGH FRIDAY NIGHT: MID TO UPPER LEVEL MOISTURE WILL BEGIN TO INCREASE ACROSS THE AREA ON WEDNESDAY AS THE THE NEXT MID LEVEL TROUGH IS FORECAST TO DEEPEN AND SHIFT EASTWARD. THIS WILL HELP TO SHARPEN THE LEE SIDE TROUGH ACROSS THE AREA AND LEAD TO A BETTER CHANCE OF LATE DAY/EVENING SHOWERS AND STORMS ACROSS MAINLY THE NORTHWESTERN PIEDMONT. THE LATEST GFS BUFR SOUNDINGS ARE SHOWING A FAIRLY DEEP DRY SUB-CLOUD LAYER WITH THE EXPECTED LOW LEVEL WESTERLY FLOW. THUS... IF ANY STRONG CONVECTION IS ABLE TO MOVE INTO THE AREA EXPECT WE WOULD HAVE A THREAT FOR SOME STRONG TO SEVERE DAMAGING WIND GUSTS. GUIDANCE IS A BIT MIXED ON HOW MUCH CONVECTION WILL MAKE IT OUR AREA THOUGH. THUS... WILL ONLY RAISE POPS INTO THE CHANCE CATEGORY ACROSS THE NORTH/NORTHWESTERN PIEDMONT LATE WEDNESDAY/WEDNESDAY EVENING... WITH MOST OF THE LINGERING CONVECTION DYING OFF BY 06Z OR SO AT THE LATEST. AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO CLIMB INTO THE 1420S TO 1430S. THUS... EXPECT WE SHOULD SEE TEMPS CLIMB INTO THE 90S... WITH POSSIBLY SOME UPPER 90S IN THE SOUTH/SOUTHEAST... WHERE CONVECTIVE CHANCES AND CLOUDS WILL BE THE LEAST. LOWS THURSDAY MORNING... WITH THE APPROACHING COLD FRONT TO THE NORTH AND WEST OF THE AREA... ARE EXPECTED TO BE IN THE UPPER 60S/AROUND 70 NW TO THE LOWER 70S ELSEWHERE... WITH EVEN SOME MID 70S POSSIBLE ACROSS THE SOUTH. THURSDAY AND FRIDAY LOOK TO BE THE MOST ACTIVE DAYS OF THE FORECAST PERIOD.... WITH THE AFOREMENTIONED TROUGH ALOFT SLOWLY CROSSING THE REGION ALONG WITH AN ACCOMPANYING WEAKENING SURFACE FRONT. THIS COMBINED WITH A MOIST AIR MASS CHARACTERIZED BY PW`S CLIMBING TO AROUND 2 INCHES WILL LEAD TO A GOOD CHANCE FOR SHOWERS AND STORMS... WITH CHANCES EACH DAY PEAKING IN THE AFTERNOON INTO THE EVENING HOURS. THE BEST DEEP LAYER SHEAR WILL REMAIN TO THE NORTH OF THE AREA. HOWEVER... WE COULD SEE DEEP SHEAR INCREASE INTO THE 20-25 KT RANGE. THUS... THIS COMBINED WITH POSSIBLY MODERATE AFTERNOON/EVENING INSTABILITY (MLCAPE VALUES DURING THE AFTERNOON APPROACHING 1500 J/KG... POSSIBLY 2000 J/KG)... THINK WE WILL HAVE AT LEAST A SMALL SEVERE THREAT... AS WE SHOULD SEE AT LEAST SOME MULTICELLULAR ACTIVITY EACH DAY. GIVEN THE MOIST AND WARM ATMO... EXPECT THE MAIN SEVERE THREAT WILL BE FROM DAMAGING WINDS. IN ADDITION.... GIVEN THE HIGH MOISTURE CONTENT AIR MASS LOCALIZED FLASH FLOODING THREAT WILL ALSO BE POSSIBLE EACH DAY. HIGHS WILL BE A BIT COOLER WITH THE ADDED CLOUD COVER AND STORMS. THUS... WILL GO WITH HIGHS GENERALLY IN THE UPPER 80S TO AROUND 90/LOWER 90S. LOWS IN THE UPPER 60S TO LOWER 70S. SATURDAY AND SUNDAY: THE MAIN MID LEVEL TROUGH AXIS IS EXPECTED TO MOVE TO THE EAST OF CENTRAL NC BY SATURDAY MORNING RESULTING IN DRYING ALOFT AND RESULTANT MUCH LESS COVERAGE OF AFTERNOON SHOWERS AND STORMS. STILL THINK WE WILL SEE SOME ISOLATED TO MAYBE WIDELY SCATTERED ACTIVITY WITH A SURFACE TROUGH REMAINING ACROSS THE REGION. WITH MORE SUN EXPECTED OVER THE WEEKEND EXPECT HIGH TEMPS WILL BE SEVERAL DEGREES WARMER AS LOW LEVEL THICKNESS VALUES ARE GENERALLY EXPECTED TO REBOUND TO AT LEAST THE 1420S. THIS WILL GENERALLY RESULT IN HIGH TEMPS BACK IN THE LOWER 90S... WITH POSSIBLY SOME MID 90S ACROSS THE SOUTH BY SUNDAY. LOWS IN THE UPPER 60S TO LOWER 70S. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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AS OF 650 AM MONDAY... AN AREA OF LOW STRATUS OVER SECTIONS OF THE SANDHILLS AND SOUTHERN PIEDMONT WITH LIFR/IFR CEILINGS WILL LIFT/DISSIPATE PRIOR TO 14Z. OTHERWISE...VFR CONDITIONS WILL PREVAIL AS A RELATIVELY DRY AIR MASS CONTINUES TO PREVAIL ACROSS CENTRAL NC. A PIEDMONT TROUGH WILL RESULT IN SW SURFACE WINDS BETWEEN 8-11KTS WITH AN INFREQUENT GUST UP TO 17KTS. SIMILAR CONDITIONS ANTICIPATED LATE TONIGHT INTO TUESDAY WITH ANOTHER ROUND OF PATCHY IFR/LIFR CEILINGS DUE TO STRATUS POSSIBLE EARLY TUESDAY MORNING. SW SURFACE WINDS TUESDAY WILL BE STRONGER WITH SUSTAINED WINDS 9-13KTS AND GUSTS AROUND 20KTS. FOR WEDNESDAY AND BEYOND...THERE WIL BE AN INCREASED THREAT FOR SCATTERED CONVECTION...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS...AS A COLD FRONT SETTLES INTO NORTH CAROLINA FROM THE NW. IN ADDITION...AN INCREASE IN LOW LEVEL MOISTURE WILL INCREASE THE PROBABILITY OF EARLY MORNING IFR/LIFR STRATUS AND MVFR/IFR FOG EACH MORNING.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS

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