Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 281932 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 335 PM EDT TUE JUL 28 2015 .SYNOPSIS...A SERIES OF PERTURBATIONS ALOFT INTERACTING WITH A MOIST AND UNSTABLE AIR MASS WILL TRIGGER ISOLATED TO SCATTERED THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVENING HOURS...THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 335 PM TUESDAY... REST OF THE AFTERNOON THROUGH THE EVENING... SCATTERED CONVECTION HAS DEVELOPED ALONG THE LEE SIDE TROUGH IN THE WESTERN PIEDMONT...AND IN VICINITY OF A WEAK/DISSIPATING SFC BOUNDARY NEAR THE VA BORDER. THE CONVECTION ACROSS SOUTHERN VA ALSO SEEMS TO BE AIDED BY A WEAK SWD DRIFTING SHEAR AXIS...DEPICTED IN THE WATER VAPOR IMAGERY. WEAK STEERING FLOW AND RELATIVELY HIGH PRECIP WATER (1.8-2 INCHES) WILL RESULT IN LOCALIZED RAINFALL RATES OF 1-1.5 INCHES. BULK OF CONVECTION WILL DIMINISH WITH LOSS OF HEATING THOUGH A FEW SHOWERS/ISOLATED STORMS MAY PERSIST WELL INTO THE EVENING OR EARLY OVERNIGHT ASSOCIATED WITH THE UPPER LEVEL SHEAR AXIS. OTHERWISE EXPECT VARYING DEGREES OF CLOUDINESS OVERNIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 335 PM TUESDAY... UPPER RIDGE CENTERED OVER THE SOUTHERN PLAINS TEMPORARILY AMPLIFIES/EXTENDS EASTWARD INTO THE CAROLINAS WEDNESDAY IN RESPONSE TO A S/W TRAVERSING THE NORTHERN PLAINS. THIS BUILDING OF HEIGHTS ALOFT WILL INDUCE A MID LEVEL CAP ON THE ATMOSPHERE...INHIBITING CONVECTIVE DEVELOPMENT OVER MOST OF THE AREA. THE EXCEPTION WILL BE THE FAR WEST AND NORTH SECTIONS OF THE CWA WHERE THE PERSISTENT LEESIDE TROUGH AND A STALLED WEAK SFC BOUNDARY WILL PROVIDE A FOCUS FOR ISOLATED-SCATTERED CONVECTION INT EH AFTERNOON-EARLY EVENING. MAX TEMPS WEDNEDAY SHOULD BE COMPARABLE TO HIGH TEMPS RECORDED TODAY (NEAR 90-LOWER 90S). POTENTIAL TO SEE A SPOT OR TWO IN THE SOUTHERN PIEDMONT/SANDHILLS FLIRT WITH MID 90S. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 300 PM TUESDAY... THE MAIN FEATURE FOR OUR AREA DURING THE LONG TERM PERIOD WILL BE THE DEEPENING LONG WAVE TROUGH OVER THE EAST. IT WILL BEGIN LATE THURSDAY AS THE TROUGH BEGINS DEEPENING OVER THE OHIO VALLEY AND MID ATLANTIC REGION...AND IN DOING SO WILL PUSH A COLD FRONT ACROSS OUR AREA THURSDAY NIGHT. WILL HAVE TO BEGIN RAMPING POPS UP ACROSS OUR WESTERN ZONES DURING THE AFTERNOON THURSDAY...BUT MOST OF DAYTIME THURSDAY SHOULD REMAIN DRY. THE BEST CHANCE FOR RAIN WILL BE THURSDAY NIGHT INTO FRIDAY MORNING...THEN RAIN CHANCES ENDING FROM W- E DURING THE AFTERNOON FRIDAY. TEMPS DURING THIS TIME NEAR NORMAL. FAIR WEATHER THEN APPEARS TO BE IN STORE FOR CENTRAL NC OVER THE WEEKEND WITH HIGH PRESSURE BUILDING TO OUR NORTH AND MUCH DRIER AIR OVER OUR REGION. THE PROGGED LOW LEVEL AIRMASS STILL APPEARS TO SUPPORT HIGHS AS WARM AS THE LOW 90S...SO LITTLE IF ANY RELIEF TEMPERATURE-WISE DESPITE HIGH PRESSURE BUILDING TO OUR NORTH. POPS EXPECTED TO REBOUND CLOSER TO DAILY CLIMO VALUES AS WE HEAD THROUGH EARLY NEXT WEEK AND PWAT SLOWLY RECOVERS. HOWEVER... COVERAGE SHOULD BE ISOLATED AT BEST GIVEN THE BETTER SYNOP FEATURES REMAINING BOTH TO OUR NORTH AND TO OUR SOUTH. IT`S WORTH NOTING THAT GIVEN THE LINGERING BOUNDARY AND LOW PRESSURE TO OUR SOUTH DURING THIS TIME...ANY SLIGHT NORTHWARD SHIFT IN THE PATTERN COULD MEAN HIGHER RAIN CHANCES FOR US DURING THE WEEKEND AND EARLY NEXT WEEK...ESP ACROSS OUR SOUTHERN ZONES. SO GIVEN OUR PROXIMITY TO THESE FEATURES...OUR CONFIDENCE IN THIS PART OF THE FORECAST ISN`T PARTICULARLY HIGH. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 125 PM TUESDAY... HIGH PROBABILITY THAT VFR CONDITIONS WILL PREVAIL AT MOST TAF SITES THROUGH WEDNESDAY AFTERNOON. THE EXCEPTION WILL BE A BRIEF PERIOD OF MVFR CONDITIONS THIS AFTERNOON THROUGH EARLY EVENING ASSOCIATED WITH SCATTERED CONVECTION. THIS OCCURRENCE IN MORE PROBABLE AT KGSO/KINT AND POSSIBLY KRDU. IN ADDITION...THERE MAY BE A HOUR OR TWO WINDOW OF IFR CONDITIONS EARLY WEDNESDAY MORNING ATTRIBUTED TO PATCHY FOG AND/OR LOW CLOUDS. THIS OCCURRENCE APPEARS MORE LIKELY AT KRWI AND POSSIBLY KFAY. OTHERWISE...CENTRAL NC WILL REMAIN IN A TYPICAL SUMMER PATTERN WITH VFR CONDITIONS INTERRUPTED BY BRIEF INSTANCES OF AFTERNOON-EVENING MVFR DUE TO CONVECTION...AND EARLY MORNING IFR CONDITIONS DUE TO PATCHY FOG AND LOW CLOUDS. AFTERNOON COVERAGE MAY BE ENHANCED FRIDAY AS A SFC FRONT DRIFTS SWD ACROSS THE REGION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...RAH AVIATION...WSS

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