Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 020524 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 125 AM EDT SAT AUG 2 2014 .SYNOPSIS... THE COMBINATION OF A UNSEASONABLY STRONG UPPER TROUGH AND A NEARLY STATIONARY SURFACE FRONT WILL KEEP VERY MOIST CONDITIONS ACROSS THE REGION THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 937 PM FRIDAY... A HISTORICAL (FOR MID SUMMER) HYBRID COLD AIR DAMMING DEVELOPED TODAY OVER CENTRAL NC IN RESPONSE TO THE ALMOST WINTER-LIKE PATTERN THAT IS RELATIVELY UNHEARD OF DURING THE LAST WEEK IN JULY AND THE FIRST WEEK OF AUGUST OF ANY YEAR. A 1022 MB SURFACE HIGH PRESSURE ACTUALLY STRENGTHENED TODAY AS IT WAS CENTERED OFF THE NJ COAST... AND EXTENDED SW ACROSS THE PIEDMONT OF NC/SC INTO GA. A MID/UPPER TROUGH OVER THE REGION... UNSEASONABLY STRONG UPPER JET... AND A VORTICITY MAXIMUM TRACKING IN THE SW FLOW ALOFT FORCED STRONG LIFT TO PRODUCE WIDESPREAD RAIN. IT WAS A GOOD SOAKING OF 1 TO 2 INCHES ACROSS A GOOD PORTION OF THE PIEDMONT REGION... WITH LESS WIDESPREAD BUT STILL LOCALLY HEAVY RAIN AMOUNTS IN THE SE ZONES. IN ADDITION... A WEAK SURFACE LOW PRESSURE DEVELOPED ALONG THE NEARLY STATIONARY FRONT OVER THE SANDHILLS AND COASTAL PLAIN THAT PLACED A PORTION OF SOUTHEASTERN NC INTO THE WARM SECTOR... WHILE THE VAST MAJORITY OF CENTRAL NC COOLED UNDER THE LOW CLOUDS... RAIN... FOG... AND NE FLOW. GREENSBORO RECORDED THE COOLEST MAXIMUM TEMPERATURE EVER FOR THE AUGUST 1 DATE... 68 DEGREES. THIS WAS 20 DEGREE BELOW THE 30 YEAR AVERAGE AND 4 DEGREES LOWER THAN THE PREVIOUS RECORD DAILY COOLEST MAXIMUM RECORDED IN 2010 OF 72 DEGREES. EVEN THE HOTTEST PLACES ON AVERAGE IN NC HAD THEIR DAILY HIGHS REMAIN IN THE 70S TODAY. FAYETTEVILLE RECORD 77 (14 DEGREES BELOW NORMAL). MID EVENING CONDITIONS CONTINUED TO BE DOMINATED BY THE HYBRID DAMMING EVENT... WITH THE 1023 MB HIGH PRESSURE CENTERED OFF THE VA COAST... BUT EXTENDING SW ACROSS THE PIEDMONT OF THE CAROLINAS INTO GA. THE TEMPERATURES WERE IN THE 60S THROUGHOUT CENTRAL NC... EXCEPT RIGHT ALONG AND ON THE WARM SIDE OF THE NEARLY STATIONARY BOUNDARY EXTENDING FROM SW TO NE ACROSS THE COASTAL AREA (OUR SOUTHERN SAMPSON COUNTY MARKED THE LOCATION OF THE BOUNDARY OVER OUR REGION). EVERYONE TO THE WEST AND NORTH OF THE BOUNDARY REPORTED A LOW OVERCAST WITH OCCASIONAL LIGHT RAIN... MIST... FOG... AND A NORTHERLY WIND. THE BOUNDARY HAS SHIFTED ABOUT 25 MILES EAST THIS EVENING IN RESPONSE TO THE PASSING OF A WEAK LOW PRESSURE... WITH GOLDSBORO AND FAYETTEVILLE NOW SOLIDLY ON THE COOLER AND MORE STABLE SIDE. OVERNIGHT... MOST MODELS SUGGEST THE BOUNDARY WILL STALL... THEN BEGIN TO SHIFT BACK WESTWARD INTO THE COASTAL PLAIN LATER TONIGHT AND SATURDAY MORNING AS ANOTHER UPPER LEVEL DISTURBANCE APPROACHES IN THE FLOW ALOFT. OCCASIONAL LIGHT RAIN OR DRIZZLE IS EXPECTED OVERNIGHT... WITH A CHANCE OF SHOWERS WITH HEAVY RAIN AGAIN LATER TONIGHT IN THE SE. THIS CHANCE WILL THEN SHIFT BACK NW ON SATURDAY. OTHERWISE... OVERNIGHT... COOL AND CLOUDY WITH THE OCCASIONAL LIGHT RAIN. LOWS 60-65 EXCEPT UPPER 60S SE. ADDITIONAL QPF SHOULD AVERAGE FROM A FEW HUNDREDTHS TO AROUND 0.25 SE. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... AS OF 300 PM FRIDAY... THE UNSETTLED PATTERN WILL CONTINUE FOR SATURDAY AS THE UPPER LEVEL TROUGH REMAINS CAMPED TO OUR WEST WITH AN INVERTED COASTAL TROUGH AT THE SURFACE. THIS WILL HELP FOCUS PRECIPITATION EAST OF HIGHWAY 1 ON SATURDAY WITH A RELATIVE MINIMUM IN THE TRIAD ALTHOUGH ALL AREAS COULD EXPERIENCE RAIN BY THE END OF THE DAY. MODELS ARE STILL HIGHLY VARIABLE ON HOW MUCH QPF EXACTLY WILL FALL WITH ANYTHING FROM 0 TO 3 INCHES POSSIBLE AT ANY GIVEN LOCATION. WILL GO WITH A FORECAST OF A WIDESPREAD QUART TO A HALF OF AN INCH IN THE WEST AND RANGING UPWARDS OF AN INCH TO AN INCH AND A HALF IN THE EAST WITH LOCALLY HIGHER TOTALS. WHILE THERE SHOULD BE GOOD INSTABILITY IN THE EAST...THE SHEAR WILL NOT BE AS GOOD AS IT WAS TODAY AND NOT MANY STRONG SHORT WAVES MOVING THROUGH THE UPPER FLOW TO PROVIDE ANY SUPPORT FOR THUNDERSTORMS. THEREFORE THERE SHOULD BE GOOD COVERAGE OF RAINFALL ACROSS THE AREA TOMORROW WITH BETTER THUNDERSTORM COVERAGE ACROSS THE EAST...BUT NOT TOO MUCH IN THE WAY OF SEVERE WEATHER. VERY SHORT STRAIGHT HODOGRAPHS PRETTY MUCH RULE OUT ANY ISOLATED TORNADO THREAT AS WELL. HIGH TEMPERATURES IN THE UPPER 70S TO LOWER 80S ACROSS THE AREA. RAIN IS EXPECTED TO CONTINUE INTO SATURDAY NIGHT WITH IFR CEILINGS AGAIN LIKELY. LOW TEMPS IN THE MID 60S TO LOWER 70S. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 200 PM FRIDAY... LITTLE CHANGE IS SHOWN IN THE PATTERN ON SUNDAY WITH THE LONGWAVE TROUGH AXIS STILL CENTERED OVER THE OH AND TN VALLEYS...AND MOIST SOUTHERLY FLOW CONTINUING ACROSS THE CAROLINAS. SEVERAL EMBEDDED SHORT WAVES WITHIN THIS FLOW ARE PROGGED TO MOVE NE AND ACROSS THE CENTER AND EASTERN PORTIONS OF THE STATE SUNDAY AND SUNDAY NIGHT... BRINGING THE CHANCE FOR SHOWERS AND TSTMS WITH EACH WAVE. GIVEN LIMITED INSTABILITY BUT HIGH PWAT VALUES AROUND 2 INCHES...THE MAIN IMPACT CONCERN DURING THIS TIME WILL BE THE ONGOING CHANCE FOR LOCALIZED POOR DRAINAGE FLOODING. NOTED THAT THE PWAT DOES DECREASE WESTWARD...THUS THE HIGHEST RISK FOR HEAVY RAIN AND SUBSEQUENT FLOODING APPEARS TO BE ACROSS THE EASTERN HALF OF OUR CWA. THE UPPER TROUGH AXIS WILL MAKE SLOW EASTWARD PROGRESSION MONDAY AND TUESDAY...WITH ITS PASSAGE AND THE PASSAGE OF THE ASSOC SFC COLD FRONT ACROSS CENTRAL NC SOMETIME DURING THE MIDDLE OF THE WEEK. THE RESULT WILL BE THE CONTINUED CHANCE FOR SCATTERED SHOWERS AND TSTMS DURING THIS TIME...WITH PERHAPS A BRIEF DECREASE IN THE RAIN CHANCE TOWARD THE MIDDLE OF THE WEEK AFTER THE FRONT MOVES ACROSS. WILL HAVE TO KEEP A SMALL CHANCE FOR RAIN DURING THE LATTER HALF OF THE WEEK...SINCE THE SFC BOUNDARY LOOKS LIKE IT MAY STALL ACROSS OR JUST SOUTH OF OUR AREA. TEMPS DURING THE LONG TERM PERIOD WILL BE LARGELY DEPENDENT ON CLOUD COVER AND PRECIP. FOR NOW WILL STAY CLOSE TO NORMAL TEMPS DURING THIS TIME...WITH THE UNDERSTANDING THAT DAYTIME TEMPS MAY BE SOMEWHAT COOLER DEPENDING ON THE TIMING AND COVERAGE OF THE CLOUDS AND RAIN. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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AS OF 125 AM SATURDAY... HIGH CONFIDENCE THAT WIDESPREAD LIFR/IFR CONDITIONS WILL PERSIST THROUGH MID-LATE MORNING. AFTERWHICH...CEILINGS WILL SLOWLY LIFT INTO THE MVFR/LOW END VFR RANGE BY THIS AFTERNOON. ISOLATED TO SCATTERED SHOWERS WILL OCCUR THROUGH LATE MORNING ALONG A STATIONARY FRONT POSITIONED OVER THE COASTAL PLAIN. THESE SHOWERS WILL BE IN THE VICINITY OF KFAY AND KRWI. AFTER 16Z...HEATING OF THE MOISTURE RICH AIR MASS WILL TRIGGER SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS. GREATEST LIKELIHOOD OF SHOWERS OR STORMS AFFECTING A TERMINAL WILL BE KFAY AND KRWI. SIMILAR CONDITIONS ANTICIPATED FOR SUNDAY EXCEPT THAT THE TRIAD TERMINALS WILL HAVE A BETTER CHANCE OF VFR CONDITIONS BY SUNDAY AFTERNOON. AVIATION CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE MONDAY AS THE AIR MASS SLOWLY DRIES OUT AND THE BETTER LIFT FOR SHOWERS AND THUNDERSTORMS DRIFTS EAST TOWARD THE IMMEDIATE COASTLINE. STILL...THERE WILL BE PERIODS OF MVFR/IFR CEILINGS DUE TO RESIDUAL MOISTURE...MAINLY IN THE LATE NIGHT-EARLY MORNINGS HOURS. FOR TUESDAY AND WEDNESDAY...A RETURN OF MORE TYPICAL SUMMER-LIKE CONDITIONS ANTICIPATED WITH EARLY MORNING MVFR/IFR PARAMETERS DUE TO FOG/LOW CLOUDS GIVING WAY TO VFR CONDITIONS WITH SCATTERED CONVECTION AND ASSOCIATED MVFR CONDITIONS DURING THE HOTTEST PART OF THE DAY.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH SUNDAY EVENING FOR NCZ028-043-078-088-089. && $$ SYNOPSIS...32 NEAR TERM...32 SHORT TERM...ELLIS LONG TERM...NP AVIATION...WSS

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