Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 200733 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 330 AM EDT SAT SEP 20 2014 .SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK SLOWLY NORTHEAST ALONG THE CAROLINA COAST THROUGH SUNDAY AS A COLD FRONT APPROACHES THE MOUNTAINS FROM THE WEST. HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTH EARLY TO MID NEXT WEEK...IN THE WAKE OF A DRY COLD FRONTAL PASSAGE MONDAY MORNING. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 230 AM SATURDAY... AN UPPER LEVEL TROUGH EXTENDING NORTHEAST FROM THE FL PANHANDLE INTO CENTRAL PORTIONS OF THE CAROLINAS WILL TEMPORARILY STALL OVER THE REGION THROUGH TONIGHT. DPVA ON THE EASTERN PERIPHERY OF THE UPPER LEVEL TROUGH WILL FOSTER CYCLOGENESIS ALONG A BAROCLINIC ZONE PRESENT ALONG/JUST OFFSHORE THE FL/GA COAST TODAY...WITH GRADUAL STRENGTHENING OF THE SFC CYCLONE AS IT TRACKS SLOWLY NORTHEAST OFFSHORE THE SC/NC COAST TONIGHT. EXPECT INCREASINGLY CLEAR SKIES WITH WESTWARD EXTENT FROM THE HWY 1 CORRIDOR WHERE SYNOPTIC SUBSIDENCE WILL PREVAIL ON THE WESTERN PERIPHERY OF THE STALLED UPPER LEVEL TROUGH WHERE FCST SOUNDINGS (I.E. AT INT/GSO) INDICATE A DRY COLUMN AND PRONOUNCED MID-LEVEL SUBSIDENCE INVERSION. ALTHOUGH MOISTURE WILL INCREASE AND MID-LEVEL TEMPS WILL DECREASE HEADING EAST TOWARD THE COAST...CENTRAL NC WILL LARGELY REMAIN ON THE SUBSIDENT SIDE OF THE UPPER LEVEL TROUGH...WITH THE BEST CHANCE OF PRECIPITATION ALONG THE CAROLINA COAST....THOUGH ISOLD SHOWER ACTIVITY CANNOT BE RULED OUT IN THE FAR SE COASTAL PLAIN WHERE LOW- LEVEL MOISTURE ADVECTION FROM THE ATLANTIC AND DIURNAL HEATING RESULT IN MARGINAL DESTABILIZATION. WILL INDICATE A DRY FORECAST EVERYWHERE EXCEPT PERHAPS A SLIGHT CHANCE OF LOW-TOPPED SHOWERS IN SAMPSON/WAYNE/CUMBERLAND OR SAMPSON ALONE WITH HIGHS IN THE LOWER 80S. DRY CONDITIONS WILL PREVAIL EVERYWHERE OVERNIGHT WITH LOWS RANGING FROM THE UPPER 50S WEST TO LOWER 60S EAST. -VINCENT && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 245 AM SATURDAY... DRY/SUBSIDENT CONDITIONS WILL PREVAIL SUNDAY AS THE STALLED UPPER LEVEL TROUGH BECOMES PROGRESSIVE...MOVING OFFSHORE WITH THE ATTENDANT SFC LOW. POTENT SHORTWAVE ENERGY DIGGING THROUGH THE GREAT LAKES INTO THE OH VALLEY WILL PROPEL A COLD FRONT EAST TOWARD THE APPALACHIANS ON SUNDAY. THE FRONT WILL CROSS CENTRAL NC MONDAY MORNING AS THE AFOREMENTIONED SHORTWAVE ENERGY TRACKS ACROSS THE NORTHERN MID-ATLANTIC. POOR DIURNAL TIMING WILL LIKELY RULE OUT ANY POTENTIAL FOR CONVECTION IN ASSOC/W THE FRONTAL PASSAGE...AND WILL MAINTAIN DRY CONDITIONS EVERYWHERE THROUGH SUN NIGHT. HIGHS ON SUN IN ADVANCE OF THE FRONT IN THE MID 80S...LOWS IN THE LOWER/MID 60S GIVEN FROPA CLOSE TO SUNRISE. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/...
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AS OF 330 AM SATURDAY... DRY AND COOL TO START THE WEEK... THEN INCREASING CLOUDS/COOL LATE WEEK... A LARGE SPRAWLING SURFACE HIGH PRESSURE IS FORECAST TO PUSH A COLD FRONT THROUGH OUR REGION EARLY MONDAY. MODELS ARE IN GOOD AGREEMENT IN DEPICTING THE LACK OF MOISTURE ASSOCIATED WITH THE FRONTAL PASSAGE. THEREFORE... ESSENTIALLY NIL POP AND QPF FOR MONDAY. GOOD DRY AND COOL AIR ADVECTION WILL COMMENCE LATER MONDAY THROUGH TUESDAY. DRY AND COOL CONDITIONS ARE FORECAST INTO WEDNESDAY COURTESY OF THE STRONG HIGH. MODELS HAVE YET TO RESOLVE DIFFERENCES IN SOLUTIONS FOR MID TO LATE WEEK. SEVERAL OPERATIONAL MODELS INDICATE A WEAKNESS ALOFT OVER THE SOUTHERN APPALACHIANS OR OVER OUR REGION BY THU-FRI. SOME MODELS AND ENSEMBLES HAVE LESS IN THE WAY OF A WEAKNESS ALOFT. REGARDLESS... IT DOES APPEAR THAT MOISTURE WILL BEGIN TO INCREASE FROM OFF THE ATLANTIC AS THE SURFACE HIGH SHIFTS OFF THE NEW ENGLAND COAST ESPECIALLY LATE WED INTO THU. JUST HOW DEEP THIS MOISTURE BECOMES SHOULD BE DETERMINED BY THE HEIGHTS ALOFT WHICH MAY NOT BE RESOLVED FOR A FEW MODEL CYCLES. THEREFORE... THE ONLY CHANCES MADE TO THE FORECAST WERE TO INCREASE TEMPERATURES A BIT MONDAY WITH MORE IN THE WAY OF SUN EXPECTED (PARTLY SUNNY SKIES... BECOMING MOSTLY SUNNY IN THE AFTERNOON)... AND LESS POP WITH THE EARLY MORNING COLD FRONTAL PASSAGE (NOW NIL). HIGHS GENERALLY 77-82 N TO SE. MUCH COOLER TUE-WED WITH SOME UPPER 40S IN THE COOLER RURAL PIEDMONT AND SANDHILLS LOCATIONS UNDER MOSTLY CLEAR SKIES AT NIGHT... THEN HIGHS ONLY 70-75 WITH MOSTLY SUNNY SKIES. WE WILL SHOW A TREND TOWARD INCREASING CLOUDINESS AND LOWER AFTERNOON HIGHS THU-FRI DUE TO THE ATLANTIC FLOW AND POTENTIAL FOR A WEAKNESS ALOFT. POP MAY HAVE TO BE INCREASED IN LATER FORECASTS IF THE EC/CANADIAN TEND TO VERIFY BETTER.
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&& .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 230 AM SATURDAY... HIGH PRESSURE EXTENDING DOWN THE EAST COAST WILL RESULT IN MAINLY VFR CONDITIONS OVER THE NEXT 24 HOURS... AND SKIES ARE BECOMING MOSTLY CLEAR OVER MUCH OF THE AREA. WINDS WILL REMAIN LIGHT OUT OF THE NORTH TO NORTHEAST. A DEVELOPING AREA OF LOW PRESSURE OFFSHORE WILL SPREAD A VEIL OF HIGH CLOUDS ACROSS THE EAST HALF OF NC LATE SATURDAY THROUGH EARLY SUNDAY. A MOISTURE STARVED COLD FRONT WILL THEN APPROACH FROM THE NW SUNDAY AND CROSS CENTRAL NC SUNDAY NIGHT THROUGH EARLY MONDAY. EXPECT A PERIOD OF VFR CEILINGS WITH THE PASSAGE OF THE FRONT SUNDAY NIGHT THROUGH LATE THE LATE MORNING HOURS ON MONDAY. AN EXPANSIVE DRY AIR SURFACE RIDGE WILL RESULT IN DRY VFR CONDITIONS THROUGH THE MIDDLE PART OF NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...PWB AVIATION...VINCENT

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