Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 260730 CCA AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 330 AM EDT WED AUG 26 2015 .SYNOPSIS...A STALLED FRONT WILL PERSIST IN VICINITY OF THE CAROLINA COAST THROUGH THE DURATION OF THE WEEK. && .NEAR TERM /OVERNIGHT/... AS OF 935 PM TUESDAY... 00Z MESO-ANALYSIS DEPICTS A TONGUE OF MOISTURE AND INSTABILITY ACROSS THE COASTAL PLAIN...AND INTO THE EASTERN SECTIONS OF THE SANDHILLS. PRECIP WATER VALUES WERE AVERAGING 1.6-1.7 INCHES IN THIS REGION. FARTHER WEST...PRECIP WATER VALUES AVERAGED 1.1 INCHES. WATER VAPOR IMAGERY SUGGESTED A SHEAR AXIS EDGING SLOWLY EAST ACROSS EASTERN NC. THIS FEATURE INTERACTING WITH AVAILABLE MOISTURE AND MODEST INSTABILITY WAS TRIGGERING A FEW SHOWERS ALONG AND EAST OF HIGHWAY 1...MAINLY IN VICINITY OF WILSON...AND OVER SECTIONS OF THE WESTERN SANDHILLS. LATEST RUC MODEL SUGGEST A VORT MAX AND ATTENDANT SHEAR AXIS DRIFTING EAST ALONG THE SC-NC BORDER THROUGH THE PRE-DAWN HOURS. BASED ON HOW WELL ISOLATED-SCATTERED CONVECTION HAS MAINTAINED ITSELF THROUGH MID EVENING AND NEAR TERN MODELS SUGGESTING A THREAT LASTING WELL INTO THE NIGHT...WILL MAINTAIN A SLIGHT-SMALL CHANCE POP...GENERALLY ALONG AND EAST OF I-95 THROUGH THE PRE-DAWN HOURS. ANOTHER SHEAR AXIS NOTED CROSSING THE TN-LOWER OH VALLEY THIS EVENING...APPROACHING THE SOUTHERN-CENTRAL APPALACHIANS. WHILE MOISTURE IS MORE LIMITED OVER WESTERN NC...THIS FEATURE MAY ENHANCE CLOUDINESS A BIT AND POSSIBLY TRIGGER A SPRINKLE OR TWO OVERNIGHT IN VICINITY OF THE TRIAD. IN ANTICIPATION OF MORE CLOUDINESS...HAVE RAISED MIN TEMPS ABOUT TWO DEGREES IN SOME SPOTS...ESPECIALLY IN THE NW PIEDMONT. MIN TEMPS SHOULD VARY FROM THE MID 60S NW TO AROUND 70 SE. && .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 /FRIDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY... IN THE WAKE OF THE EASTERN US TROUGH LIFTING NEWD INTO EASTERN CANADA...WEAK TROUGHINESS WILL EXTEND FROM THE CENTRAL GULF NORTHWARD INTO THE LOWER MS VALLEY AS THE SUBTROPICAL RIDGE OVER THE WESTERN ATLANTIC RETROGRADES TOWARDS THE SOUTHEAST COAST. MEANWHILE AT THE SURFACE...WEAK SURFACE HIGH WILL SLIDE EASTWARD OVER THE MID- ATLANTIC STATES...WHICH SHOULD NUDGE THE LINGERING SURFACE FRONTAL BOUNDARY EVER SO SLIGHTLY SOUTHEASTWARD...REMAINING NEAR THE SOUTHEAST COAST THROUGH THE WEEKEND. UNDER INCREASING HEIGHTS ALOFT AND WEAK SFC HIGH PRESSURE...FRIDAY AND SATURDAY LOOKS MOSTLY DRY ACROSS CENTRAL NC WITH RAIN CHANCES MAINLY CONFINED TO THE DIFFERENTIAL HEATING OVER MTNS AND FTHLS AND ALONG THE IMMEDIATE COAST INVOF OF THE LINGERING SFC BOUNDARY. BY SUNDAY...SHOWERS AND STORMS COULD RETURN TO THE AREA...ESPECIALLY ACROSS WESTERN PORTION S OF THE STATE WHERE THE APPROACH OF MID/UPPER LEVEL SHORTWAVE TROUGH OVER THE UPPER MS VALLEY/LOWER GREAT LAKES COULD KICK THE LINGERING WEAK TROUGHINESS OVER LOWER MS VALLEY EASTWARD INTO THE AREA. SEASONABLE TEMPERATURES WITH HIGHS IN THE MID TO UPPER 80S. LOWS 65 TO 70. FORECAST CONFIDENCE DECREASES BY EARLY NEXT WEEK DUE TO UNCERTAINTY OF HOW MUCH SUBTROPICAL RIDGING EXISTS OVER THE SOUTHEAST...WHICH WILL GREATLY DETERMINE THE EVOLUTION TRACK OF TC ERICKA. 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. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 200 AM WEDNESDAY... 24 HOUR TAF PERIOD: ALL THE SENSIBLE WEATHER IN THE TAF PERIOD WILL MOST LIKELY OCCUR IN THE EASTERN HALF OF THE AREA WITH KFAY AND KRWI BEING THE PRIMARY TERMINALS AFFECTED. AS FAR AS CONVECTION IS CONCERNED...THERE ARE CURRENTLY SHOWERS AND THUNDERSTORMS IN THE VICINITY OF KFAY AND THESE ARE EXPECTED TO CONTINUE FOR THE NEXT SEVERAL HOURS BUT WEAKEN OVER TIME. OF SECONDARY CONCERN WILL BE AREAS OF FOG THIS EVENING...PARTICULARLY AT KRWI AND KFAY. TO THIS POINT...ANY OBSERVATIONS OF VISIBILITY RESTRICTIONS HAVE BEEN IN THE MVFR RANGE AND THIS IS EXPECTED TO BE THE PRIMARY CATEGORY FOR THE EVENING WITH AN OUTSIDE CHANCE OF SOME IFR CONDITIONS...ESPECIALLY AFTER THE RAIN AT KFAY. LATER IN THE DAY EXPECT ANOTHER ROUND OF CONVECTION IN THE EAST...WITH KRWI AND KFAY ONCE AGAIN THE MOST LIKELY AFFECTED HOWEVER IT IS POSSIBLE THAT SHORTWAVE ENERGY WILL HELP SOME ISOLATED SHOWER ACTIVITY FURTHER WEST IN THE VICINITY OF KRDU NEAR THE END OF THE TAF PERIOD. LONG TERM: WITH THE FRONTAL ZONE STALLING OUT OVER THE EASTERN HALF OF THE STATE...TERMINALS ALONG AND EAST OF ROUTE 1 WILL BE UNDER CONTINUED THREAT FOR DAILY SHOWERS AND THUNDERSTORMS...PARTICULARLY DURING AFTERNOON PEAK HEATING. TRIAD TERMINALS SHOULD REMAIN LARGELY VFR FOR MUCH OF THE WEEK BUT UNCERTAINTY INCREASES TOWARDS THE WEEKEND WHEN THE FRONTAL ZONE COULD RETROGRADE A LITTLE AS A WEAK LOW FORMS SOUTH OF THE AREA. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...WSS SHORT TERM...VINCENT LONG TERM...CBL AVIATION...ELLIS

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