Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 290709 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 309 AM EDT FRI AUG 29 2014 .SYNOPSIS...A SLOW MOVING BACK DOOR COLD FRONT WILL STALL OUT ACROSS CENTRAL NORTH CAROLINA TODAY. THE FRONT WILL GRADUALLY DISSIPATE OVER THE WEEKEND AS A LIGHT SOUTHERLY RETURN FLOW DEVELOPS ACROSS THE REGION. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 235 AM FRIDAY... OVERVIEW: AN UPPER LEVEL RIDGE CENTERED OVER THE SOUTHEAST STATES WILL EXTEND N/NE INTO THE MID-ATLANTIC TODAY/TONIGHT. A WEST-EAST ORIENTED BACK DOOR COLD FRONT LOCATED JUST SOUTH OF THE VA/NC BORDER AT 06Z THIS MORNING IS EXPECTED TO STALL OUT IN VICINITY OF THE HWY 64 CORRIDOR TODAY. BELOW AVERAGE CONFIDENCE IN THE FORECAST THROUGH TONIGHT. MODEL GUIDANCE CONTINUES TO VARY WITH THE PRECISE POSITION AND ORIENTATION OF THE STALLED FRONT TODAY...IN ADDITION TO THE PRECISE ORIENTATION OF THE LOW-LEVEL HEIGHT GRADIENT. AS A RESULT...POSSIBLE SOLUTIONS RANGE FROM A HYBRID COLD AIR DAMMING WEDGE AND ELEVATED CONVECTION DEVELOPING BETWEEN 12-18Z TODAY NORTH OF HWY 64 TO NO WEDGE DEVELOPMENT AND A SOMEWHAT TYPICAL POTENTIAL FOR ISOLD TO SCT SFC- BASED CONVECTION. GIVEN THE SUBTLE NATURE OF THE PATTERN IN PLACE AND THAT CONVECTION COULD LARGELY DICTATE THE EVOLUTION OF THE LOW- LEVEL PATTERN...WILL LEAVE THE FORECAST ROUGHLY AS-IS WITH A SLIGHT TO LOW CHANCE (20-30%) OF CONVECTION AND HIGHS RANGING FROM THE MID 80S NORTH TO LOWER 90S SOUTH. LOWS TONIGHT NEAR 70F. -VINCENT && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 220 AM FRIDAY... CENTRAL NC WILL REMAIN UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE SAT/SAT NIGHT AS THE CENTER OF THE RIDGE CURRENTLY OVER THE SOUTHEAST STATES SHIFTS SLIGHTLY EAST TOWARD THE COAST. THE LINGERING FRONTAL ZONE OVER PORTIONS OF CENTRAL NC SHOULD WASH OUT DURING THE DAY AS A LIGHT S/SE RETURN FLOW DEVELOPS ACROSS THE REGION. FORECAST SOUNDINGS SUGGEST MARGINAL DESTABILIZATION WITH 500- 1500 J/KG OF MLCAPE SAT AFTERNOON. GIVEN A PROTOTYPICAL SUMMERTIME `RIDGE` PATTERN...EXPECT ABOVE NORMAL TEMPS...IN THE LOWER 90S. MARGINAL INSTABILITY AND SEASONABLE MOISTURE (PWAT VALUES OF 1.50- 1.75") WOULD SUPPORT ISOLD CONVECTION ON SATURDAY...THOUGH FORCING FOR ASCENT WILL BE LIMITED TO THE SEABREEZE AND DIFFERENTIAL HEATING...PRIMARILY ALONG THE HIGHER TERRAIN IN WESTERN NC...AND IT IS POSSIBLE THAT NO CONVECTION WILL DEVELOP IN CENTRAL NC. WITH THE ABOVE IN MIND...WILL INDICATE A SLIGHT CHANCE OF CONVECTION DURING THE AFT AND EARLY EVE HOURS IN THE WESTERN PIEDMONT AND SE COASTAL PLAIN. EXPECT NEAR NORMAL LOWS SAT NIGHT IN THE UPPER 60S TO LOWER 70S. -VINCENT && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 245 AM FRIDAY... A RIDGE WILL BUILD OVER THE SOUTHEASTERN STATES EARLY TO MID WEEK. THIS WILL EXTEND OUR CURRENT MORE SUMMER-LIKE PATTERN ACROSS NC WELL INTO WEDNESDAY. THE CORE OF THE UPPER RIDGE IS FORECAST TO BE OVER THE NC/SC COAST SUNDAY. THE APPROACHING UPPER TROUGH FROM THE OHIO VALLEY WILL BE DEFLECTED TO OUR NORTH AND WEAKEN SUNDAY NIGHT AND MONDAY. EVEN WITH THE HEAT AND HUMIDITY WITH THE SOUTHERLY RETURN FLOW... ONLY ISOLATED AFTERNOON THUNDERSTORMS ARE EXPECTED. THE BEST CHANCE IS FORECAST OVER AND NEAR THE BLUE RIDGE WHERE INSTABILITY... MOISTURE... AND LIFT WILL BE HIGHEST. HIGHS SHOULD REACH THE 88-93 RANGE. THE CORE OF THE UPPER RIDGE IS FORECAST TO SHIFT SOUTHWEST WITH TIME TO OVER THE GULF COAST STATES TUE-WED. THIS WILL ALLOW A WEAK PIEDMONT TROUGH AT THE SURFACE WHICH MAY AID IN THE DEVELOPMENT OF SCATTERED THUNDERSTORMS DURING THE AFTERNOON AND EVENING EARLY TO MID WEEK. OTHERWISE... SIMPLY WARM AND HUMID WITH PARTLY CLOUDY SKIES. LOWS 69-74. HIGHS 88-93 NW TO SANDHILLS. FOR MID TO LATE WEEK... ANY SURFACE FRONT IS EXPECTED TO BE WEAK AND PROVIDE LITTLE IF ANY COOLING OR DRYING. HOWEVER... IT MAY ACT AS A CONTINUED FOCUS FOR SCATTERED MAINLY AFTERNOON THUNDERSTORMS WED- FRI. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 150 AM FRIDAY... 24-HR TAF PERIOD: BELOW AVERAGE CONFIDENCE IN THE FORECAST THROUGH TONIGHT. A BACK DOOR COLD FRONT ORIENTED WEST-EAST ACROSS SOUTHERN VA AT 06Z WILL MOVE SLOWLY SOUTH TOWARD THE NC BORDER TODAY... EVENTUALLY STALLING OUT NEAR OR JUST SOUTH OF THE BORDER ACROSS THE NORTHERN PIEDMONT. MODEL GUIDANCE CONTINUES TO VARY CONSIDERABLY WITH REGARD TO CEILINGS AND PRECIP CHANCES TODAY INTO TONIGHT. THE 00Z NAM INDICATES A HYBRID COLD AIR DAMMING WEDGE WITH MVFR/IFR CEILINGS AND ELEVATED SHOWER ACTIVITY DEVELOPING BETWEEN 12-18Z AT ALL OF THE NORTHERN TERMINALS (INT/GSO/RDU/RWI)...WHILE THE GFS INDICATES VFR CONDITIONS PREVAILING OUTSIDE OF MVFR CONDITIONS ASSOC/W ISOLD SFC-BASED CONVECTION. WITH LITTLE INDICATION ONE WAY OR THE OTHER...WILL SPLIT THE DIFFERENCE AND INTRODUCE A TEMPO GROUP FOR BKN015 BETWEEN 12-16Z EVERYWHERE EXCEPT THE FAY TERMINAL. LOOKING AHEAD: EXPECT A NEAR CLIMATOLOGICAL PATTERN THROUGH EARLY NEXT WEEK WITH A SLIGHT CHANCE OF AFTERNOON/EVENING CONVECTION AND A POTENTIAL FOR EARLY MORNING FOG/STRATUS. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...PWB AVIATION...VINCENT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.