Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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810 FXUS62 KRAH 201749 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 149 PM EDT WED MAY 20 2015 .SYNOPSIS...
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A FRONT STALLED TO THE SOUTH THIS AFTERNOON WILL RETREAT NORTHWARD AS A WARM FRONT ON THURSDAY AS A DEVELOPING LOW PRESSURE SYSTEM TRACKS EAST ACROSS THE CAROLINAS.
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&& .NEAR TERM /THROUGH TONIGHT/...
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AS OF 130 PM WEDNESDAY... TODAY: EXPECT MOSTLY CLEAR SKIES THIS AFTERNOON IN ASSOCIATION WITH A DRY/STABLE AIRMASS WHICH ADVECTED INTO THE REGION IN THE WAKE OF A RECENT COLD FRONTAL PASSAGE. HIGHS WILL RANGE FROM THE LOWER 80S IN THE NORTHERN PIEDMONT /NEAR VA BORDER/ TO UPPER 80S NEAR THE SC BORDER IN CLOSER VICINITY TO THE STALLED FRONTAL ZONE...WHICH EXTENDS WESTWARD FROM SOUTHERN/COASTAL SC INTO THE DEEP SOUTH. TONIGHT: SHORTWAVE ENERGY CROSSING THE LOWER MS RIVER VALLEY THIS AFTERNOON WILL TRACK EASTWARD INTO NC OVERNIGHT...IN ADVANCE OF ADDITIONAL SHORTWAVE ENERGY DIGGING SOUTHEAST FROM THE NORTHERN PLAINS INTO THE UPPER MS RIVER VALLEY. WEAK DPVA ATTENDANT THE APPROACHING SHORTWAVE WILL RESULT IN THE DEVELOPMENT OF A WEAK CYCLONE ALONG THE STALLED FRONTAL ZONE THIS EVENING. THE SFC LOW WILL STRENGTHEN AND GRADUALLY CONSOLIDATE OVER WESTERN NORTH CAROLINA (IN VICINITY OF CHARLOTTE) LATE TONIGHT AS DPVA ATTENDANT THE APPROACHING SHORTWAVE IS AUGMENTED BY SYNOPTIC HEIGHT FALLS ATTENDANT UPSTREAM SHORTWAVE ENERGY DIGGING INTO THE UPPER MS RIVER VALLEY. 925-850 MB SOUTHERLY FLOW /WARM ADVECTION/ ON THE EASTERN PERIPHERY OF THE LOW WILL ADVECT A HIGHER THETA-E AIRMASS NORTHWARD INTO WESTERN AND CENTRAL NC TONIGHT...RESULTING IN ELEVATED DESTABILIZATION WITH MUCAPE INCREASING TO AT 250-750 J/KG. ISOLD ELEVATED SHOWERS WILL BE POSSIBLE BY MIDNIGHT IN THE W/SW PIEDMONT...WITH CHANCES INCREASING BETWEEN 06-12Z AS WEAK DPVA PROGRESSES INTO THE CAROLINAS FROM THE WEST. EXPECT LOWS RANGING FROM UPPER 50S NE COASTAL PLAIN TO MID 60S IN THE SOUTH...ESP NEAR THE SC BORDER AND IN SW PIEDMONT. -VINCENT
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&& .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... AS OF 430 AM WEDNESDAY... WHILE THE MODELS ARE IN GENERAL AGREEMENT THAT SFC LOW PRESSURE WILL TRACK EAST ACROSS NC ON THU...THEY STILL DIFFER WITH REGARD TO THE DEGREE OF DESTABILIZATION AND HOW FAR NORTH THE PRECEDING WARM FRONT WILL RETREAT IN ADVANCE OF THE LOW. THOUGH THESE UNCERTAINTIES EXIST...BACKED LOW LEVEL FLOW PRECEDING THE SFC LOW...IN CONJUNCTION WITH STRENGTHENING MID LEVEL FLOW AT THE BASE OF TROUGH AMPLIFICATION ALOFT OVER THE GREAT LAKES...WILL YIELD A FAVORABLY- SHEARED ENVIRONMENT FOR ORGANIZED STORM MODES. IN FACT...IT APPEARS THAT INITIALLY ELEVATED CONVECTION DURING THE MORNING HOURS WILL BECOME INCREASINGLY SURFACE-BASED WITH DIURNAL DESTABILIZATION AND THE RETREAT OF THE WARM FRONT...WITH AREAS ALONG AND SOUTH OF HIGHWAY 64 AND EAST OF HIGHWAY 1 FAVORED FOR MOST OPTIMAL DESTABILIZATION. DAMAGING WINDS AND AN ISOLATED TORNADO WILL POSE THE PRIMARY THREATS. HIGH TEMPERATURES WILL BE WIDE-RANGING GIVEN BOTH THE PRESENCE OF THE FRONT AND CONVECTION - LOW TO MID 70S NORTH TO MID 80S SOUTH. A CHANCE OF SHOWERS AND STORMS WILL LINGER INTO THE EVENING HOURS...UNTIL A COLD FRONT TRAILING THE SFC WAVE SETTLES SOUTH OVERNIGHT. LOWS GENERALLY 55 TO 60 DEGREES. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... WITH THE SURFACE LOW RACING AWAY FROM THE NC COAST AND THE ATTENDANT COLD FRONT WELL SOUTH OF CENTRAL NC FRIDAY MORNING...A QUIET PERIOD OF WEATHER WILL RESUME AS A RELATIVELY STRONG 1030MB CANADIAN HIGH BUILDS OVER THE MID-ATLANTIC STATES. LOW LEVEL THICKNESSES AS LOW AS 1350M...30M BELOW NORMAL...FRIDAY MORNING SUGGESTS HIGHS IN THE MID 70S AT BEST AND LOWS POTENTIALLY IN THE LOW TO MID 50S FRIDAY NIGHT...THOUGH SOME UPPER 40S ARE EVEN POSSIBLE WITH A LONGER PERIOD OF DECOUPLING ACROSS THE NORTH. THE SURFACE HIGH WILL THEN SHIFT OFFSHORE ON SATURDAY AND ALLOW RETURN FLOW AND MODERATION TO COMMENCE...WITH TEMPS TO REBOUND INTO THE 80S BY SATURDAY/SUNDAY AND APPROACH 90 MONDAY/TUESDAY AS THE SUBTROPICAL RIDGE BUILDS BACK ACROSS THE SOUTHEAST US. PROVIDED THE RIDGE BUILDS AS STRONGLY AS ADVERTISED ...DRY CONDITIONS ARE EXPECTED THROUGH THE PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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AS OF 130 PM WEDNESDAY... VFR CONDITIONS WILL PREVAIL THROUGH MIDNIGHT IN ASSOC/W A DRY AIRMASS IN PLACE ACROSS CENTRAL NC. CEILINGS ARE EXPECTED TO DETERIORATE TO MVFR/IFR BY 08-12Z AT ALL TERMINALS AS A WARM FRONT LIFTS NORTHWARD INTO CENTRAL NC...IN ADVANCE OF A DEVELOPING SFC LOW TO THE WEST. ELEVATED SHOWERS WILL BE POSSIBLE AT ALL TERMINALS BETWEEN 09-15Z THU...FOLLOWED BY A CHANCE FOR SFC-BASED SHOWERS AND THUNDERSTORMS BETWEEN 15-21Z THU AT THE RDU/FAY/RWI TERMINALS. VFR CONDITIONS WILL RETURN IN THE WAKE OF A COLD FRONTAL PASSAGE FROM WEST-EAST THURSDAY AFTERNOON AND EVENING. LOOKING AHEAD: VFR CONDITIONS WILL RULE THROUGH THE WEEKEND AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST. -VINCENT
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...26 LONG TERM...22 AVIATION...VINCENT

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