Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 271821 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 220 PM EDT WED MAY 27 2015 .SYNOPSIS...BERMUDA HIGH PRESSURE CENTERED OVER THE WESTERN ATLANTIC WILL PREVAIL THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1020 AM WEDNESDAY... STRONG MID/UPPER LEVEL RIDGE OFF THE EASTERN SEABOARD MAY WEAKEN A BIT WHILE DRIFTING EVER SO SLIGHTLY EASTWARD. MEANWHILE...BERMUDA HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL KEEP A WARM HUMID AIRMASS IN PLACE. SOME SHOWER ACTIVITY HAS DEVELOPED IN EASTERN SC AND SOUTHEASTERN NC AND IS TRACKING TO THE NORTHEAST. THIS IS LIKELY IN RESPONSE TO A WEAK DISTURBANCE WITHIN THE SOUTHEASTERLY FLOW ALOFT. THESE WEAK DISTURANCES WILL BE THE MAIN TRIGGERS FOR ANY CONVECTION INTO THE AFTERNOON AS WELL. HOWEVER...A LEFT-OVER OUTFLOW BOUNDARY FROM CONVECTION OVERNIGHT ACROSS THE WESTERN PIEDMONT MAY ALSO SERVE AS A FOCUS FOR CONVECTIVE INITIATION LATER TODAY. IN ADDITION...AN AREA OF STRATUS ACROSS THE NORTHEAST PIEDMONT AND SANDHILLS HAS BEEN SLOW TO BURN OFF THIS MORNING. SO DIFFERENTIAL HEATING ALONG THE BOUNDARIES OF THIS AREA OF CLOUD COVER COULD ALSO SERVE AS A TRIGGER. ALL OF THIS WILL LEAD TO SCATTERED AFTERNOON STORMS...WITH SLIGHTLY HIGHER COVERAGE THAN PREVIOUS DAYS. WEAK/MARGINAL ML CAPE BETWEEN 500-1000 J/KG COUPLED WITH DEEP LAYER SHEAR OF 10-15 KTS WILL FAVOR DISORGANIZED CONVECTION WITH LITTLE TO NO SEVERE THREAT. MOISTURE WILL BE SLIGHTLY HIGHER TODAY AND GIVEN THE BETTER CLOUD COVER AND SLIGHTLY HIGHER PRECIP CHANCES...HIGH TEMPS SHOULD BE A COUPLE OF DEGREES LOWER THAN YESTERDAY. HIGHS ARE EXPECTED TO BE IN THE LOW/MID 80S ACROSS THE NORTHWEST AND MID/UPPER 80S ACROSS THE SOUTHEAST. PRECIP SHOULD DIMINISH AFTER SUNSET...BUT PLENTY OF CLOUDS AND MOISTURE WILL BE AROUND OVERNIGHT...KEEPING TEMPS FROM FALLING MUCH. THEREFORE...OVERNIGHT LOWS ARE EXPECTED TO BE IN THE MID/UPPER 60S. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 300 AM WEDNESDAY... MID AND UPPER-LEVEL FLOW BECOMES INCREASINGLY MORE WESTERLY ON THURSDAY AS THE SHORTWAVE TROUGH OVER THE LOWER GREAT LAKES PROGRESSES EASTWARD INTO SOUTHERN NEW ENGLAND THROUGHOUT THE DAY. IN RESPONSE...MODELS HINT AT WEAK LEE-SIDE TROUGHINESS DEVELOPMENT ACROSS THE WESTERN PIEDMONT...WHILE DRIFTING THE LINGERING VORTICITY SHEAR AXIS EASTWARD INTO THE COASTAL PLAIN. WITH CONTINUED SEASONABLY MOIST AIR IN PLACE...THESE TWO FEATURES ALONG WITH DIURNAL DESTABILIZATION WILL SERVE AS A FOCUS FOR SCATTERED CONVECTION THURSDAY AFTERNOON/EARLY EVENING. PERSISTENCE TEMPERATURE FORECAST WILL BE FOLLOWED. HIGHS 83 TO 88. LOWS IN THE MID TO UPPER 60S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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AS OF 220 PM WEDNESDAY... ON FRIDAY...THE UPPER RIDGE WILL STRENGTHEN OVER THE SOUTHEAST... KEEPING THE BEST CHANCE FOR MAINLY DIURNAL SHOWERS/TSTMS TO OUR WEST...ALTHOUGH CAN`T COMPLETELY REMOVE POPS JUST YET FROM OUR TRIAD ZONES. WITH THE RIDGE STILL IN PLACE ON SATURDAY...LOOK FOR THE BEST CHANCE FOR SHOWERS/TSTMS TO BE MAINLY TO OUR NORTH AND WEST NEAR THE DEEPER MOISTURE...AND TO OUR EAST ALONG THE SEA BREEZE. LATE IN THE WEEKEND INTO MONDAY...THE FORECAST FOCUS WILL SHIFT TO THE NEXT FRONT APPROACHING FROM THE NORTHWEST. WHILE THE GFS PUSHES THE FRONT FARTHER SOUTH THAN THE ECMWF...BOTH MODELS KEEP THE BULK OF THE DEEPER MOISTURE TO OUR NORTH...CONSEQUENTLY KEEPING THE BEST CHANCE FOR SHOWERS/TSTMS N OF HWY 64...ALTHOUGH WILL HAVE TO KEEP AN EYE TO OUR EAST TO SEE HOW FAR ANY SEA BREEZE ACTIVITY CAN PUSH INLAND. FOR THE MIDDLE OF NEXT WEEK...A COMPLICATED PATTERN APPEARS TO BE EVOLVING WITH A CLOSED LOW MEANDERING OVER THE LOWER MISS VALLEY OR GULF COAST REGION...AND THE RIDGE CENTERED TO OUR NORTHEAST. WHILE CONFIDENCE IN DETAILS IS LOW RIGHT NOW...PERSISTENT MOIST SOUTHERLY FLOW OVER OUR AREA SUGGESTS AT LEAST CLIMO-POPS EACH DAY...DESPITE LACK OF MAJOR FORCING MECHANISMS. TEMPS: LOW LEVEL THICKNESSES ARE FORECAST TO REMAIN STEADY OR GRADUALLY CLIMB THROUGH THE WEEKEND AHEAD OF THE COLD FRONT...THEN FALL EARLY NEXT WEEK AS A SFC RIDGE BUILDS DOWN FROM THE NORTH. HIGHS IN THE UPPER 80S TO NEAR 90 FRIDAY AND OVER THE WEEKEND WILL BE REPLACED BY HIGHS CLOSER TO NORMAL (LOWER-MIDDLE 80S) EARLY- MIDDLE NEXT WEEK. LOWS IN THE 60S EACH DAY.
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&& .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 130 PM WEDNESDAY... MOST OF CENTRAL NC HAS RETURNED TO VFR CONDITIONS...ALTHOUGH A FEW LINGERING MVFR CIGS REMAIN. SCATTERED SHOWERS/STORMS ACROSS THE AREA (BEST COVERAGE CURRENTLY ACROSS THE SOUTH AND EAST) WILL FILL IN ACROSS THE REGION THROUGH THE AFTERNOON HOURS. CONDITIONS ARE EXPECTED TO REMAIN LARGELY VFR THROUGH AT LEAST THE LATE EVENING HOURS...ALTHOUGH BRIEF SUB-VFR CONDITIONS WILL BE POSSIBLE IN ANY OF THE HEAVIER STORMS. HAVE INCLUDED A MENTION OF THUNDER AT KRDU...KFAY AND KRWI WHERE COVERAGE LOOKS TO BE THE GREATEST. HOWEVER...CANNOT RULE OUT THUNDER AT ANY TAF SITE. CONVECTIVE ACTIVITY IS EXPECTED TO DIMINISH AFTER SUNSET. ANOTHER ROUND OF LOW STRATUS/FOG WILL BE LIKELY AREAWIDE TOWARDS THE PRE-DAWN HOURS OF THURSDAY. ANY SUB-VFR CONDITIONS THAT DO DEVELOP SHOULD LIFT/DISSIPATE BY 15-16Z ON THURSDAY. OUTLOOK...THE THREAT FOR RESTRICTIONS IN EARLY MORNING FOG/STRATUS WILL CONTINUE INTO THE WEEKEND AS BERMUDA HIGH PRESSURE HOLDS OVER THE AREA. ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE EXPECTED AGAIN ON THURSDAY. RAIN CHANCES WILL BEGIN TO DECREASE SOME INTO THE WEEKEND AS THE UPPER LEVEL RIDGE RETROGRADES WEST OVER THE AREA. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...KRD/CBL SHORT TERM...CBL LONG TERM...RAH AVIATION...KRD/CBL

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