Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 021717 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 120 PM EDT SUN AUG 2 2015 .SYNOPSIS... AN AREA OF LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL TRACK SLOWLY NORTHEAST ALONG A NEARLY STATIONARY FRONT OVER THE SOUTHEAST U.S. THROUGH MONDAY NIGHT. MEANWHILE WEAK HIGH PRESSURE WILL REMAIN CENTERED FROM THE TN VALLEY TO THE CENTRAL APPALACHIANS. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 AM SUNDAY... WEAK HIGH PRESSURE AT THE SURFACE WILL CONTINUE TO INFLUENCE THE WEATHER ACROSS THE PIEDMONT TODAY WHILE A STALLED SURFACE FRONT IN VICINITY OF THE NC COAST MAY CAUSE A FEW MORE CLOUDS AND A VERY SLIGHT CHANCE OF A STORM OVER THE FAR SE COUNTIES. A DRY WLY FLOW ALOFT COUPLED WITH THE SFC RIDGE SHOULD PROVIDE PLENTY OF SUN TO MOST OF CENTRAL NC THIS AFTERNOON. WITH THICKNESSES IN THE 1425-1435M RANGE...AFTERNOON TEMPS IN THE 90-95 DEGREE RANGE APPEAR ATTAINABLE. SIMILAR TO SATURDAY...SFC DEWPOINTS WILL REMAIN COMFORTABLE...IN THE 50S TO NEAR 60...THOUGH SLIGHTLY HIGHER IN THE FAR COASTAL PLAIN WHERE DEWPOINTS IN THE LOWER 60S WILL BE COMMON. IF A SHOWER OR STORM WERE TO OCCUR...IT WOULD MOST LIKELY BE TO THE EAST AND SOUTH OF CLINTON AND GOLDSBORO AND LIKELY NOT UNTIL 5 PM OR LATER. -WSS FORECAST CONFIDENCE DECREASES LATER TONIGHT...AS A WEAK WAVE OF LOW PRESSURE OVER THE NORTHEASTERN GULF OF MEXICO TRACKS SLOWLY UP THE SOUTHEAST US COAST. MOIST SOUTHERLY FLOW AROUND THE LOW...DIRECTED INTO THE EASTERN CAROLINAS...WILL LIKELY RESULT IN THE NORTHWARD DEVELOPMENT/EXPANSION OF AN AREA OF LOW CLOUDS...AND EVEN A FEW SHOWERS INTO THE SOUTHERN COASTAL PLAIN. THE ASSOCIATED LOW CLOUDS MAY CREEP AS FAR WEST AS THE PIEDMONT PER THE 00Z/ECMWF... WHICH INITIALIZED MUCH BETTER WITH LOW LEVEL MOISTURE VALUES THAN THE DRIER/CLEARER GFS SOLUTIONS...THOUGH THE MOISTURE WOULD LIKELY BE TOO SHALLOW AND CAPPED TO SUPPORT ANY PRECIPITATION THERE. LOWS RANGING FROM THE MIDDLE 60S IN THE RESIDUALLY DRY/CONTINENTAL AIR MASS OVER THE PIEDMONT...PARTICULARLY THE WESTERN HALF...TO AROUND 70 DEGREES OR SO OVER THE COASTAL PLAIN. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 415 AM SUNDAY... MODEL SPREAD REMAINS RELATIVELY LARGE WITH THE TRACK AND SPEED OF THE WAVE OF LOW PRESSURE FORECAST TO RIPPLE NORTHEAST ALONG THE FRONT OVER THE EASTERN CAROLINAS MON AND MON NIGHT. GIVEN THE POORLY- ANALYZED MOISTURE FIELDS IN THE GFS NOTED IN THE NEAR TERM...WILL WEIGHT THE FORECAST TOWARD THE SLIGHTLY MORE WESTWARD TRACK AND ASSOCIATED (MOSTLY) CLOUDIER AND WETTER CONDITIONS OVER THE COASTAL PLAIN INDICATED BY THE 00Z/2ND ECMWF AND GEM. SUCH A SOLUTION WOULD RESULT IN LESS HOT TEMPERATURES OVER THE COASTAL PLAIN...IN THE UPPER 80S TO AROUND 90 DEGREES...TO LOWER 90S ACROSS THE REMAINDER OF CENTRAL NC. IF THE DAY PROVES DRIER AND MOSTLY SUNNY AREA- WIDE...PERSISTENCE HIGH TEMPERATURES IN THE LOWER TO MIDDLE 90S WOULD AGAIN OCCUR. ANY LINGERING RAIN CHANCE SHOULD END OVER THE FAR EASTERN NC COASTAL PLAIN BY MIDNIGHT...AS THE LOW LIFTS NE AND AWAY FROM THE NC OUTER BANKS. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 245 AM SUNDAY... THURSDAY AND WEDNESDAY: LOW PRESSURE OVER CANADA WILL LIFT NORTHWARD AND UPPER LEVEL PATTERN OVER CENTRAL NC WILL BE VERY ZONAL WITH A GRADUAL SHIFT TO WEST SOUTHWESTERLY FLOW BY WEDNESDAY. WITH THE JET LIFTING NORTHWARD DURING THIS PERIOD AND MOST OF THE UPSTREAM SHORTWAVE ACTIVITY REMAINING WELL TO THE NORTHWEST...EXPECT GENERALLY DRY CONDITIONS DURING THIS PERIOD WITH THE OCCASIONAL DIURNAL SHOWER POPPING UP ON SURFACE BOUNDARIES SUCH AS THE SEA BREEZE. SOUTHWESTERLY SURFACE FLOW WILL KEEP TEMPERATURES UP WITH HIGHS IN THE MID 90S AND LOWS IN THE LOW TO MIDDLE 70S. THURSDAY THROUGH SATURDAY: THE FORECAST BECOMES MUCH MORE LOW CONFIDENCE BY THE END OF THE WEEK BUT THERE ARE A FEW THINGS WE DO KNOW FOR SURE. NUMBER ONE IS THAT MOISTURE WILL BE INCREASING SIGNIFICANTLY OVER THE AREA. NUMBER TWO IS THAT SEVERAL SHORTWAVE IMPULSES UPSTREAM WILL MAKE THEIR WAY INTO THE AREA OR AT LEAST SKIRT CLOSE ENOUGH TO THE ARE TO AFFECT OUR WEATHER HERE IN CENTRAL NC. THREE IS THAT ALTHOUGH MOISTURE IS INCREASING...INSTABILITY AND SHEAR ARE NOT INCREASING ALL THAT MUCH...THEREFORE WHILE WE CAN EXPECT INCREASE CONVECTIVE ACTIVITY BEGINNING ON THURSDAY THROUGH THE WEEKEND...THE LIKELIHOOD OF SEVERE WEATHER IS STILL FAIRLY SMALL. TOUGHER TO DETERMINE WILL BE THE TIMING OR EXACT LOCATIONS OF CONVECTIVE ACTIVITY LATE IN THE WEEK. MODELS HAVE NOT BEEN CONSISTENT AT ALL WITH TIMING THE LAST SEVERAL DAYS AND CONTINUE TO FLUCTUATE. CURRENTLY...MODELS ARE PREDICTING THE FIRST SHORTWAVE TO MOVE THROUGH ON THURSDAY. THERE WILL BE A GAP BETWEEN THE FIRST AND SECOND SHORTWAVE WHICH IS DUE TO ARRIVE FRIDAY EVENING WHICH MAY LINGER OVER THE AREA FOR A WHILE BEFORE POTENTIALLY DEVELOPING A FULL ON SURFACE LOW ON SATURDAY AS IT SLIDES OFF OF THE EAST COAST. INCREASED CLOUD COVER AND CONVECTIVE ACTIVITY WILL BRING TEMPERATURES DOWN INTO THE MID 80S TO LOWER 90S DURING THIS PERIOD BUT WITH THE INCREASED MOISTURE...RELATIVE HUMIDITIES WILL INCREASE. LOWS DURING THE PERIOD UPPER 60S TO LOWER 70S. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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AS OF 120 PM SUNDAY... HIGH PROBABILITY THAT VFR CONDITIONS WILL PERSIST AT TAF SITES ACROSS CENTRAL NC THROUGH MONDAY NIGHT. THE EXCEPTION WILL BE IN VICINITY OF KFAY AND KRWI WHERE A BRIEF PERIOD OF MVFR/IFR VISIBILITY DUE TO FOG AND POTENTIALLY IFR CEILINGS MAY OCCUR VERY LATE TONIGHT THROUGH EARLY MONDAY MORNING. ASIDE FROM A SMALL THREAT FOR EARLY MORNING MVFR/IFR FOG EACH MORNING...EXPECT VFR CONDITIONS TUESDAY THROUGH WEDNESDAY. THE PROBABILITY FOR MVFR CEILINGS WILL INCREASE THURSDAY AND MORE SO FRIDAY AS THE ATMOSPHERE BECOMES MORE MOIST AND THE APPROACH OF AN UPPER LEVEL DISTURBANCE WILL LIKELY ENHANCE THE CHANCE FOR SCATTERED CONVECTION. CURRENT MODEL TIMING FAVORS THURSDAY NIGHT INTO FRIDAY FOR SCATTERED CONVECTION AREAWIDE.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS/26 NEAR TERM...WSS/26 SHORT TERM...26 LONG TERM...ELLIS AVIATION...WSS

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