Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 251717 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 115 PM EDT TUE AUG 25 2015 .SYNOPSIS...A STALLED FRONT WILL PERSIST IN VICINITY OF THE CAROLINA COAST THROUGH THE DURATION OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 100 PM TUESDAY... CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE MID-ATLANTIC AND CAROLINAS THROUGH TONIGHT...EQUATORWARD OF AN UNSEASONABLY STRONG UPPER LEVEL LOW STALLED ALONG THE NORTHERN PERIPHERY OF THE GREAT LAKES IN SOUTHERN ONTARIO. A COLD FRONT PROGRESSING INTO THE COASTAL PLAIN THIS MORNING WILL STALL IN VICINITY OF THE CAROLINA/SOUTHEAST COAST THIS AFTERNOON INTO TONIGHT. PRECISELY WHERE THE FRONT WILL BE LOCATED THIS EVE/TONIGHT REMAINS DIFFICULT TO ASCERTAIN GIVEN THAT A WEAK WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE BOUNDARY AS IT APPROACHES STALLED SHORTWAVE ENERGY ALONG THE SOUTHEAST COAST...AMIDST WEAK SYNOPTIC HEIGHT FALLS /STRENGTHENING CYCLONIC FLOW ALOFT/. ADDITIONALLY...CONVECTION /OUTFLOW/ AND DIFFERENTIAL HEATING THIS AFTERNOON MAY ALSO INFLUENCE THE POSITION OF THE FRONT. GIVEN THE LATEST OBSERVATIONAL DATA...EXPECT DRY CONDITIONS ALONG/WEST OF HWY 1 (TRIANGLE WESTWARD)...WITH A POTENTIAL FOR ISOLD/SCT CONVECTION TO THE EAST...PRIMARILY IN THE SOUTHEAST COASTAL PLAIN. EXPECT COOLER HIGHS IN THE MID TO UPPER 80S DEPENDING ON CLOUD COVER AND CONVECTION/OUTFLOW. A DIURNAL WANE IN CONVECTIVE COVERAGE IS EXPECTED AFTER SUNSET...THOUGH SOME POTENTIAL FOR ISOLD CONVECTION WILL PERSIST OVERNIGHT IN VICINITY OF THE STALLED FRONTAL ZONE/WEAK SURFACE LOW...PRIMARILY IN THE SOUTHEAST COASTAL PLAIN. LOWS RANGING FROM THE LOWER 60S IN THE N/NW PIEDMONT TO THE UPPER 60S /NEAR 70F/ IN THE FAR SE COASTAL PLAIN. -VINCENT && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 100 PM TUESDAY... LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED ON WED...WITH THE UNSEASONABLY STRONG UPPER LEVEL LOW STALLED NORTH OF THE GREAT LAKES...CYCLONIC FLOW ALOFT ALONG THE EASTERN SEABOARD...AND A STALLED FRONTAL ZONE IN VICINITY OF THE CAROLINA/SOUTHEAST COAST. AS A RESULT...EXPECT CONDITIONS ON WED TO BE SIMILAR TO TODAY...WITH THE BEST POTENTIAL FOR CONVECTION IN COASTAL/FAR-EASTERN NORTH CAROLINA. WILL KEEP PRECIP CHANCES GENERALLY CONFINED TO THE FAR SE COASTAL PLAIN COUNTIES (I.E. CUMBERLAND/SAMPSON/WAYNE). ADDITIONAL SHORTWAVE ENERGY DIGGING SOUTHEAST ALONG THE WESTERN PERIPHERY OF THE STALLED UPPER LOW IS PROGGED TO PROGRESS INTO THE CENTRAL APPALACHIANS LATE WED NIGHT...AND IT IS POSSIBLE THAT THE FRONTAL ZONE SHIFTS FURTHER INLAND (ALONG WITH A POTENTIAL FOR PRECIP) AFTER MIDNIGHT AS LOW-LEVEL WIND/HEIGHT FIELDS RESPOND TO THE APPROACHING SHORTWAVE. FORECAST CONFIDENCE REMAINS LOW WITH REGARD TO THE EVOLUTION/TIMING OF THE APPROACHING WAVE...THE STALLED FRONTAL ZONE...AND WHETHER AN INLAND SHIFT IN PRECIPITATION WILL OCCUR (AS THE GFS SUGGESTS) OR PRECIPITATION REMAINS ALONG THE COAST (AS THE NAM SUGGESTS). -VINCENT && .LONG TERM /THURSDAY THROUGH TUESDAY/...
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AS OF 115 PM TUESDAY... FRONTAL ZONE REMAINS PINNED ALONG THE NC COAST AS MILD HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES AND SOUTH DOWN THE EASTERN SPINE OF THE APPALACHIANS INTO THE WEEKEND. MEANWHILE...ALOFT...THE FRONTAL ZONE LIES BETWEEN A WEAK UPPER TROF OVER THE ATLANTIC COAST AND STRONGER OFFSHORE RIDGE WHICH WILL BEGIN TO RETROGRADE INTO THE SOUTHEAST ATLANTIC COAST...PROVIDING ADDITIONAL MOISTURE AS WELL AS NUDGING THE FRONT SLOWLY INLAND. WILL KEEP THE CHANCE OF RAIN ONLY MARGINALLY ABOVE CLIMATOLOGICAL...~30%...AND FOCUSED PRIMARILY ON THE SOUTHEAST THROUGH SATURDAY. CLOUDINESS WILL BECOME MORE PREVALENT ON SATURDAY AS OVERRUNNING EASTERLY FLOW SETS UP...WHICH COULD LEAD TO INCREASING POPS AS THE WEEKEND APPROACHES. HIGHS EACH DAY WILL BE PRETTY NEAR CLIMATOLOGICAL...POTENTIALLY COOLER ON SATURDAY...POSSIBLY SUNDAY AS WELL...IF THE DAMMING AND PRECIP SCENARIO MATERIALIZES. UNCERTAINTY INCREASES BY EARLY NEXT WEEK AS WE WILL POTENTIALLY BE SUBJECT TO THE INFLUENCE OF TS ERIKA. WE WILL BE IN THE WEAK TROF AREA BETWEEN AN AMPLIFYING RIDGE IN THE MIDWEST AND THE STRONGER AND STILL RETROGRADING SUBTROPICAL RIDGE OVER THE SOUTHWEST ATLANTIC...WHICH SHOULD BE THE DETERMINING STEERING MECHANISM FOR ERIKA OR HER REMAINS. REGARDLESS...HEIGHTS WILL INCREASE EARLY NEXT WEEK AND SHOULD SEE AN UPTICK IN TEMPS...UPPER 80S TO LOWER 90S MONDAY AND TUESDAY...WITH AT LEAST WIDELY SCATTERED DIURNAL CONVECTION IN THE MOIST AIRMASS. STAY TUNED.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 100 PM TUESDAY... 24 HOUR TAF PERIOD: SUB-VFR CONDITIONS ASSOC/W SCATTERED CONVECTION WILL BE POSSIBLE AT THE FAY TERMINAL TODAY IN ASSOC/W A SLOW MOVING COLD FRONT THAT WILL STALL OVER FAR EASTERN PORTIONS OF THE CAROLINAS THIS AFTERNOON THROUGH TONIGHT. CHANCES FOR CONVECTION SHOULD DIMINISH THIS EVENING/TONIGHT. MVFR/IFR CEILINGS MAY DEVELOP DURING THE PRE-DAWN HOURS WED MORNING AT THE FAY/RWI TERMINALS... PARTICULARLY THE FAY TERMINAL IN CLOSER VICINITY TO THE STALLED FRONTAL ZONE. FURTHER WEST AT THE INT/GSO/RDU TERMINALS...VFR CONDITIONS AND A LIGHT NORTHERLY WIND ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD. LOOKING AHEAD: A POTENTIAL FOR CONVECTION AND LOW CEILINGS WILL PERSIST AT FAY/RWI (PARTICULARLY FAY) THROUGH THE REMAINDER OF THE WEEK AS A WEAK WAVE OF LOW PRESSURE DEVELOPS AND PERSISTS ALONG THE STALLED FRONT IN VICINITY OF THE SOUTHEAST COAST. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...MLM AVIATION...VINCENT

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