Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 010852 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 452 AM EDT FRI AUG 1 2014 .SYNOPSIS... A RIDGE OF HIGH PRESSURE WILL REMAIN WEDGED OVER THE CAROLINAS THROUGH SATURDAY AS AN UPPER TROUGH REMAINS CENTERED TO OUR WEST. TO THE EAST...A FRONT WILL REMAIN NEARLY STATIONARY ALONG THE COAST ALLOWING DEEP ATLANTIC MOISTURE TO CONTINUE TO SPREAD OVER THE AREA. CONDITIONS ARE EXPECTED TO RETURN TO MORE TYPICAL LATE SUMMER CONDITIONS BY THE MIDDLE OF NEXT WEEK AS THE BERMUDA STRENGTHENS TO OUR EAST. && .NEAR TERM /THROUGH TONIGHT/... 430 AM EDT UPDATE...RAIN CONTINUES TO REFORM ACROSS THE NRN UPSTATE PRODUCING A GOOD AMOUNT OF PRECIP WITHIN THE PAST 3 HRS. DUAL POL FFMP HAS 3-HR RATIOS APPROACHING 85 PERCENT. THE ADVISORY IS COVERING THIS AREA WELL...BUT THIS MAY NEED TO BE UPGRADED TO A WARNING BY DAYBREAK IF THE RAINFALL DOESN/T SHIFT. GOOD CLEARING IS SEEN TO THE WEST WHICH WAS EXPECTED AND POPS HAVE ADJ A LITTLE MORE DOWN IN THAT AREA. THE ESCARPMENT AND NC PIEDMONT AREAS ARE NOW SEEING STEADY MODERATE RAINFALL...AREAS WHICH HAVE RELATIVELY HIGH FFG COMPARED TO THE UPSTATE. AS OF 230 AM EDT...A LIGHT TO MODERATE PRECIP SHIELD HAS BEGUN TO DEVELOP MORE INTO THE NRN MTNS AND FOOTHILLS AS WELL THE LOWER NC PIEDMONT. INSTANTANEOUS RATES ARE VARYING BTW ONE AND TWO IN/HR...WITH THE HIGHEST AMOUNTS OCCURRING ALONG THE I-85 CORRIDOR FROM BLACKSBURG TO THE CLT METRO. EXPECT THIS NORTHWARD TREND TO SLOWLY CONTINUE THROUGH THE PERIOD. THE GOOD THING IS THE HEAVIEST DOWNPOURS ARE CONTINUING TO MOVE AND ARE NOT OCCURRING WHERE THE GREATEST RAINFALL FELL PREVIOUSLY. THERE COULD BE AN ISOL HYDRO THREAT THROUGH THE MORNING...BUT THE LACK OF DEEP CONVECTION HAS LIMITED THIS POTENTIAL....YET SEE NO NEED TO EXPIRE OF THE FFA WITH AN ONGOING PRECIP EVENT. THINGS SHOULD BEGIN TO IMPROVE PRECIP/WISE THROUGH THE DAY WITH ULVL ENERGY TRANSITING NE WHILE A NEW TROF AXIS DEVELOPS TO THE WEST OF THE FA. THERE WILL BE WANING ATL MOISTURE AND SOME CONTINUED ISEN LIFT OVER A WEAKENING SFC RIDGE...BUT DEEP CONVECTIVE ENHANCEMENT AND ANCHORING CELLS ARE NOT FAVORED THIS AFTERNOON. THE LLVL FLOW WILL BECOME WEAK THROUGH H7 AND AS THE WEDGE BNDRY LOOSENS OVERALL MOISTURE FLUX WILL BE REDUCED THROUGH THE AFTERNOON...BUT THERE WILL STILL BE A THREAT FOR PULSE TSTMS WITH HEAVY RAINFALL IN AREAS OF GREATER INSTABILITY. A STATIONARY FRONT WILL REMAIN TO SE OF THE FA OVERNIGHT...ROBING MOISTURE INTO THE AREA AS DEEP CONVECTION FIRES ALONG THE COAST. PLENTY OF CLOUD COVER AND LINGERING PRECIP WILL HOLD MAX TEMPS ARND 10-12 DEGREES BELOW NORMAL...BUT AREAS OF DIFF HEATING COULD CREATE A BUST POTENTIAL. MINS WILL REMAIN A FEW DEGREES BELOW NORMAL...MID TO UPPER 60S NON/MTNS AND L60S MTN VALLEYS. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 220 AM EDT FRIDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON SATURDAY WITH THE WET PATTERN EXPECTED TO CONTINUE THROUGH EARLY NEXT WEEK. THE UPPER TROUGH AXIS WILL REMAIN WEST OF THE APPALACHIANS THRU THE WEEKEND AND GRADUALLY DRIFT EASTWARD EARLY NEXT WEEK...DEAMPLIFY A BIT...AND TAKE ON A MORE POSITIVE TILT. ON SATURDAY...AS THE WEDGE PATTERN PERSISTS DEEP LYR MOISTURE WILL REMAIN OVER THE CWFA WITH THE HIGHEST PWAT VALUES EXPECTED OVER THE SOUTHERN AND EASTERN ZONES. THE LATEST RUNS OF THE MESOSCALE MODELS INDICATE THAT THE GREATEST QPF IS MORE LIKELY SAT AFTERNOON/EVENING AS NUMEROUS LOBES OF PVA ROTATE AROUND THE UPPER TROF AND OVER THE FCST AREA. THIS COUPLED WITH THE PERSISTENT ISENTROPIC UPGLIDE SHOULD PRODUCE AT LEAST ANOTHER QUARTER TO ONE INCH OF RAINFALL OVER THE CWFA BY EARLY SUN. ON SUNDAY...A WEAK COLD FRONT WILL TRY AND PUSH ITS WAY INTO THE WESTERN CAROLINAS FROM THE NW BUT WILL LIKELY STALL SOMEWHERE OVER THE NC PIEDMONT WITH DRIER AIR BEHIND IT. OVERALL QPF POTENTIAL DOES NOT LOOK AS FAVORABLE OVER MOST OF THE CWFA WITH THE GREATEST AMOUNTS LIKELY JUST TO OUR SOUTH AND EAST ALONG THE STALLED BNDY. THE AXIS OF HEAVIER PRECIP COULD OF COURSE SHIFT DEPENDING ON HOW FAR SOUTH THE BNDY ACTUALLY MAKES IT. AT ANY RATE...I KEPT POPS AT HIGH END CHANCE TO LIKELY THRU EARLY MONDAY WITH VALUES TAPERING OFF FROM THE NW TO SE BY THE END OF MY PERIOD 12Z MONDAY. TEMPS WILL VARY LITTLE FROM DAY TO DAY WITH HIGHS WELL BELOW NORMAL AND LOWS NEAR NORMAL. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 1220 AM FRIDAY...THIS MEDIUM RANGE PERIOD BEGINNING AT 12Z MONDAY WITH THE UPPER AIR PATTERN WITH A TROUGH AXIS WEST OF THE APPALACHIANS. THIS TROUGH WILL GRADUALLY TRANSITION INTO MORE ZONAL WEST TO EAST FLOW IN MID WEEK. AS THE TROUGH BREAKS DOWN...A WEAK UPPER LOW WILL BE LEFT OVER THE LOWER MISSISSIPPI VALLEY. AS THE GENERAL WESTERLY FLOW INCREASES IN MID WEEK...OUR AIRMASS WILL BECOME DRIER AND TEMPS WILL RETURN TO NEAR NORMAL. ON MONDAY...THE STALLED OUT SURFACE FRONT FROM NRN FL TO ALONG THE CAROLINA COAST WILL HAVE WEAK LOWS RIDING NE ALONG THE FRONT. IT APPEARS THE TROPICAL LOW BERTHA IS FORECAST TO BE EAST OF THE CAROLINAS OUT TOWARD BERMUDA ON TUESDAY AS IT TURNS FROM NW TO N THEN NE AVOIDING THE EAST COAST. BY WED AND THUR WE CAN EXPECT A TYPICAL SUMMERTIME PATTERN OF PM TSTORMS FAVORING THE MTNS WITH LESS OUT OVER THE PIEDMONT. SOME UPPER ENERGY WILL BE APPROACHING FROM THE NW LATE THURS...BUT MOST EFFECTS SHOULD HOLD OFF UNTIL AFTER THE END OF THE CURRENT FORECAST. MONDAY HIGH TEMPS WILL BE AROUND 7 DEGREES BELOW NORMAL THEN REBOUND TO NEAR NORMAL WED AND THURS. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... AT KCLT...LIGHT TO MODERATE RAIN SHIELD WILL CONTINUE TO COME AND GO AT CLT THIS MORNING AND A GRADUAL LOWERING OF CIGS TO IFR ARND 10Z. NOT MUCH IMPROVEMENT TIL 15Z OR SO AS SFC HEATING WILL BE SLOW. THE TAF REMAINS PESSIMISTIC WITH MVFR CIGS EXPECTED MOST OF THE DAY THEN A DROP BACK IFR LATE ARND 03Z. THUNDER CHANCES REMAIN HIGH ENOUGH FOR PROB30 MENTION AFT 18Z. ELSEWHERE...A MIXED BAG OF CIGS/VSBY THIS MORNING DEPENDING ON THE INTENSITY AND LOCATION OF RAINFALL. ALL SITES SHOULD DROP TO LOW MVFR IF NOT IFR THIS MORNING MAINLY FOR CIGS. KAND WILL SEE THE QUICKEST IMPROVEMENT BY 15Z TO POSSIBLY VFR CONDS AS PRECIP SHIELD PUSHES NORTH. OTHER SITES WILL LIKELY TEMPO MVFR/VFR THROUGH THE DAY...WITH LOWERING CIGS TO IFR LATE IN THE TAF PERIOD. THUNDER CHANCES REMAIN HIGH ENOUGH FOR PROB30S AND VCTS THIS AFTERNOON. OUTLOOK...UNSETTLED WEATHER WITH ENHANCED PRECIPITATION CHANCES ALONG WITH MORNING FOG/STRATUS ARE EXPECTED THROUGH THE WEEKEND. CONFIDENCE TABLE... 09-15Z 15-21Z 21-03Z 03-09Z KCLT HIGH 80% HIGH 93% HIGH 90% MED 76% KGSP MED 78% HIGH 91% HIGH 80% MED 60% KAVL HIGH 84% MED 77% MED 74% HIGH 93% KHKY MED 72% HIGH 95% HIGH 100% MED 60% KGMU MED 74% HIGH 89% HIGH 80% LOW 58% KAND MED 73% MED 72% MED 69% LOW 56% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR GAZ010-017-018-026- 028-029. NC...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR NCZ033-048>053-058- 059-062>065-501>510. SC...FLASH FLOOD WATCH UNTIL NOON EDT TODAY FOR SCZ001>007-010>012- 019. && $$ SYNOPSIS...JPT NEAR TERM...SBK SHORT TERM...JPT LONG TERM...DEO AVIATION...SBK

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