Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 311046 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 645 AM EDT FRI JUL 31 2015 .SYNOPSIS...A COLD FRONT WILL PUSH SOUTHEASTWARD THROUGH THE AREA THIS MORNING... SETTLING ACROSS SOUTHEAST NORTH CAROLINA THIS AFTERNOON. HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH THE WEEKEND. && .NEAR TERM /THROUGH SATURDAY NIGHT/... AS OF 300 AM FRIDAY... TODAY/TONIGHT: ISOLATED SHOWERS AND AN OCCASIONAL LIGHTNING STRIKE PERSIST JUST AHEAD OF THE SOUTHEASTWARD-MOVING SURFACE FRONT... FROM AROUND LAKE GASTON SE TO NEAR CLT... ALTHOUGH ACTIVITY HAS SIGNIFICANTLY DWINDLED IN BOTH INTENSITY AND COVERAGE IN THE LAST FEW HOURS WITH GROWING CINH AND VANISHING CAPE AS THE LOWEST FEW HUNDRED MB COOLS. FOLLOWING THIS TREND WHICH MESHES WELL WITH THE LATEST NSSL WRF OUTPUT... HAVE MAINTAINED JUST AN ISOLATED MENTION OVER THE FAR EAST AND FAR SOUTH UP UNTIL SHORTLY BEFORE DAYBREAK... UNTIL THE REMAINING ELEVATED INSTABILITY DISAPPEARS COMPLETELY ALONG WITH THE SUPPORTIVE WEAK UPPER DIVERGENCE... ALTHOUGH EVEN SUGGESTING A 15-20% COVERAGE MAY BE TOO HIGH. AFTER A PERIOD OF DRY WEATHER THROUGH THE REST OF THE MORNING AS LOWER SURFACE DEWPOINTS SLOWLY FILTER IN FROM THE NW... WE SHOULD SEE REDEVELOPMENT THIS AFTERNOON OF SCATTERED SHOWERS/STORMS OVER THE SOUTHEAST CWA WHERE SURFACE DEWPOINTS WILL BE LAST TO FALL... LIKELY HOLDING IN THE LOWER TO PERHAPS MIDDLE 70S... YIELDING 1000-1500 J/KG OF MUCAPE. A LIKELY INLAND-MOVING SEA BREEZE SHOULD HELP FOCUS THIS CONVECTION... WITH THE BEST COVERAGE SE OF A LAURINBURG-TO-GOLDSBORO LINE. STORM STRENGTH WILL BE GREATLY LIMITED BY THE LACK OF DYNAMICS AND VERY WEAK DEEP LAYER SHEAR. THIS CONVECTION SHOULD DISSIPATE TOWARD SUNSET AS THE SURFACE-925 MB FRONTAL ZONE SHIFTS FURTHER SOUTH... PUSHED BY THE DEEPENING MID LEVEL TROUGH AXIS OVER THE EASTERN STATES. A NEARLY DRY ADIABATIC LOW LEVEL THERMAL PROFILE ALONG WITH STATISTICAL GUIDANCE SUPPORTS HIGHS OF 90-94... A SLIGHTLY UPWARD BUMP FROM THE PREVIOUS FORECAST. LOWS TONIGHT WILL BE TRICKY... WITH A GOOD CHANCE OF COOLER AIR SPILLING INTO THE NW CWA WHILE HIGHER DEWPOINTS AND TEMPS LINGER OVER THE FAR SE. EXPECT LOWS FROM THE LOW- MID 60S NW RANGING TO AROUND 70/LOWER 70S SE. SAT/SAT NIGHT: A QUIET DAY AS THE MEAN TROUGH AXIS HOLDS OVERHEAD... WITH THE SURFACE FRONTAL ZONE STRETCHING THROUGH ERN AND SE NC AS HIGH PRESSURE BUILDS IN FROM THE WNW. EXPECT A ROUND OF ISOLATED MID- LATE AFTERNOON SHOWERS AND STORMS OVER THE FAR SE WITHIN MARGINAL INSTABILITY AND WEAK LOW LEVEL MASS CONVERGENCE... WITH DRY WEATHER ELSEWHERE GIVEN THE DRY AND SUBSIDING MID LEVELS AND FALLING PW VALUES. AGAIN LEANING TOWARD A DRY ADIABATIC LOW LEVEL LAPSE RATE... EXPECT HIGHS OF 90-95... WITH LOWS SAT NIGHT 63-70. -GIH && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 200 AM FRIDAY... A STAGNANT UPPER LEVEL PATTERN WILL REMAIN IN PLACE ON SUNDAY AND MONDAY WITH A SLIGHTLY DEEPENING UPPER LEVEL TROUGH OVER THE EASTERN CONUS AND NEAR STATIONARY RIDGE OVER THE SOUTHWESTERN UNITED STATES. DURING THIS PERIOD A WEAK SURFACE HIGH OVER THE OHIO VALLEY WILL KEEP CONDITIONS RELATIVELY DRY. TO THE NORTH...A LOW PRESSURE SYSTEM NORTH OF THE GREAT LAKES WITH AN ASSOCIATED FRONTAL SYSTEM STRETCHING SOUTHWARD...WILL IMPINGE UPON THE SURFACE HIGH BY THE END OF THE SHORT TERM... HELPING TO WEAKEN THE HIGH BUT SHOULD STILL REMAIN DRY IN THE NORTHWEST PIEDMONT. THE ONLY CHANCE FOR PRECIPITATION WILL COME IN THE FORM OF POTENTIAL DIURNAL CONVECTION...PARTICULARLY IN THE FAR SOUTHEAST WHERE RETURN FLOW AROUND THE BERMUDA HIGH WILL BRING INCREASED MOISTURE INTO THE AREA WHICH COULD USE THE SEA BREEZE FRONT AS A CATALYST FOR CONVECTION DURING THE AFTERNOON/EARLY EVENING HOURS. REGARDLESS...THE AIRMASS AS A WHOLE WILL BE VERY DRY FOR THIS TIME OF YEAR WHICH WILL KEEP PRECIP CHANCES VERY LOW. HIGH TEMPERATURES WILL BE IN THE LOWER 90S WITH LOWS IN THE UPPER 60S NW TO LOW 70S SE. DEWPOINTS WILL MODERATE FROM THE LOWER 60S ON SUNDAY TO MID TO UPPER 60S BY MONDAY...RESULTING IN AND OVERALL INCREASE IN HUMIDITY. && .LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 200 AM FRIDAY... TUESDAY AND WEDNESDAY THE UPPER LEVEL PATTERN FLATTENS OUT AND BECOMES MORE ZONAL AS THE LOW PRESSURE SYSTEM OVER THE GREAT LAKES MOVES GRADUALLY NORTH AND EASTWARD. THERE WILL BE VERY LITTLE FORCING ALOFT TO HELP ANY DIURNAL CONVECTION THAT MAY FORM...PARTICULARLY ALONG THE PIEDMONT TROUGH...WHICH SHOULD SET UP AS THE SURFACE LOW SLIDES EASTWARD. THE AIRMASS WILL STILL BE VERY DRY WITH WEAK INSTABILITY AND SHEAR AND IN WITH THE ABSENCE OF ANY NOTABLE SHORTWAVE ACTIVITY...EXPECT MOSTLY DRY CONDITIONS TUESDAY AND WEDNESDAY. HIGHS BOTH DAYS IN THE LOWER TO MID 90S WITH LOWS IN THE UPPER 60S TO LOWER 70S. FORECAST CONFIDENCE BEGINS TO DECREASE GOING INTO THURSDAY AS A POTENT WAVE COMING OUT OF THE MIDWEST MOVES EASTWARD AND HELPS TO REINVIGORATE THE OLD FRONTAL BOUNDARY ASSOCIATED WITH THE LARGER SURFACE LOW IN EASTERN CANADA. MODELS DIFFER IN TIMING AT THIS STAGE WITH THE EUROPEAN COMING IN SLOWER THAN THE GFS BUT THE MESSAGE IS THE SAME. EXPECT AN INCREASE IN PRECIPITATION CHANCES AT SOME POINT ON THURSDAY AS MOISTURE INCREASES THROUGHOUT THE COLUMN. SHEAR AND INSTABILITY ARE FAIRLY WEAK AT THIS POINT BUT WITH THE EXTRA FORCING FROM THE WAVE...IT WOULD NOT BE OUT OF THE REALM OF POSSIBILITY TO SEE A WET MICROBURST OR TWO...ESPECIALLY IF TIMING SPLITS THE DIFFERENCE BETWEEN THE TWO MODELS AND COMES IN AT PEAK HEATING...WHEN THE SPREAD BETWEEN TEMPERATURE AND DEWPOINT IS MAXIMIZED. WITH INCREASED CLOUD COVER LIKELY...EXPECT HIGH TEMPS TO DROP BACK TO THE LOW 90S WITH LOWS THURSDAY NIGHT IN THE LOW 70S. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 645 AM FRIDAY... ABOVE-NORMAL CONFIDENCE IN VFR CONDITIONS DOMINATING AT CENTRAL NC TERMINALS FOR THE NEXT 24 HOURS. A COOL FRONT CURRENTLY PUSHING TOWARD THE SOUTHEAST THROUGH CENTRAL NC HAS MOVED JUST SE OF RDU... AND WITH THE DRIER POST-FRONT AIR PUSHING IN... INT/GSO/RDU ARE LIKELY TO SEE LITTLE MORE THAN SCT VFR CLOUDS (POSSIBLY BECOMING BKN BRIEFLY FRI AFTERNOON) AND UNRESTRICTED VSBYS TODAY. AT RWI/FAY... GREATER LOW LEVEL MOISTURE MAY RESULT IN THESE TWO LOCATIONS BEING ON THE EDGE OF ISOLATED TO SCATTERED SHOWERS AND STORMS THAT ARE EXPECTED TO DEVELOP WITH THE HEATING OF THE DAY COMBINED WITH AN INLAND-MOVING SEA BREEZE. THESE SHOWERS/STORMS COULD PRODUCE A PERIOD OF SUB-VFR CONDITIONS IF THEY DEVELOP NEAR FAY/RWI THIS AFTERNOON. LOOKING BEYOND 12Z FRIDAY: HIGH CONFIDENCE IN VFR CONDITIONS DOMINATING AT ALL CENTRAL NC TERMINALS THROUGH TUE. THE ONLY EXCEPTION IS THE STALLED FRONT COULD BRING A PERIOD OF MVFR FOG SAT MORNING... AND POSSIBLY BRIEF SUB-VFR CONDITIONS IN SHOWERS/STORMS TO FAY SAT AFTERNOON. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...ELLIS LONG TERM...ELLIS AVIATION...HARTFIELD

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