Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 211557 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1057 AM EST FRI NOV 21 2014 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE AREA THROUGH SATURDAY. ABUNDANT MOISTURE WILL RETURN ON SUNDAY AHEAD OF A LOW PRESSURE SYSTEM LIFTING FROM TEXAS TO THE GREAT LAKES. THE WEATHER MAY REMAIN UNSETTLED EARLY NEXT WEEK AS ANOTHER COLD FRONT APPROACHES FROM THE WEST. && .NEAR TERM /THROUGH TONIGHT/... 1050 AM EST UPDATE...HAVE INCREASED AFTERNOON MAX TEMPS BY AROUND 2-5 DEGREES EAST OF THE MTNS GIVEN THE LATEST WARMING TREND. OTHERWISE...THE CURRENT FORECAST IN ON TRACK. AS OF 630 AM EST...A POLAR AIRMASS WILL CONTINUE TO SPREAD INTO THE AREA THIS MORNING BEHIND A WEAK COLD FRONT. A TIGHT UPPER GRADIENT IS SEEN OVER THE SRN APPALACHIANS ON THE BACK SIDE OF A BROAD TROUGH. A SMALL POCKET OF MOISTURE PROGGED BY BOTH GFS AND NAM IS CROSSING THE MTNS NOW AND A WELL DEVELOPED BAND OF WAVE CIRRUS HAS FORMED. THIS BAND SHOULD DIMINISH THRU THE MORNING WITH THE MOISTURE BEING DEPLETED. SKIES OTHERWISE WILL BE NEARLY CLEAR TODAY. LONGWAVE TROUGH WILL CONTINUE TO MOVE OFFSHORE THRU TONIGHT ALLOWING THE SFC HIGH TO SPREAD TO THE MID-ATLANTIC COAST BENEATH A RATHER FLAT UPPER RIDGE. LOW LEVEL FLOW WILL CONTINUE TO VEER THIS AFTN AND TONIGHT...PERHAPS BRINGING BACK ENOUGH MOISTURE FOR PARTIAL MIDLEVEL CLOUDINESS LATE TONIGHT. SOME FAIRLY GUSTY WINDS ARE POSSIBLE THIS MORNING AND EARLY AFTN ON MTN RIDGES AS COLD ADVECTION CONTINUES AND GIVEN THE EFFECTS OF THE TIGHTER GRADIENT FLOW ALOFT. THICKNESSES CONTINUE FALLING INTO TONIGHT UNDER STILL NORTHERLY FLOW. MAX/MIN TEMPS THUS END UP 8-10 DEG BELOW CLIMO...WITH MINS TONIGHT BEING A FEW DEGREES COLDER THAN THOSE THIS AM. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 240 AM FRIDAY...THE ULVL PATTERN REMAINS FAIRLY ZONAL OR FLAT RIDGED SAT WITH A CONFLUENT ZONE PERSISTING OFF THE ATL. THIS WILL ALLOW A SFC HIGH CENTER TO MIGRATE OFF THE COAST AND A DEVELOP A HYBRID CAD OVER THE CWFA. LOW LEVEL THICKNESSES WILL MODIFY SLOWLY WHILE CLOUD COVER INCREASES FROM THE SW IN THE AFTERNOON...WHICH WILL HOLD MAX TEMPS ABOUT 10 DEGREES BELOW NORMAL. NRN GOM MOISTURE FLUX WILL INCREASE SAT NIGHT AHEAD OF A STRONG H5 S/W PUSHING OUT OF TX INTO THE LOWER MS RIVER VALLEY. A COMBINATION OF MECH AND ISEN LIFT WILL BEGIN ACROSS THE WRN ZONES AND -SHRA WILL DEVELOP AFT MIDNIGHT...PERSISTING THROUGH THE OVERNIGHT WHILE BECOMING MORE WIDESPREAD THROUGH DAYBREAK. A PERIOD OF -SNSH IS POSSIBLE ACROSS THE NRN NC MTNS OVERNIGHT WHERE MINS DROP BELOW FREEZING ACROSS THE HIGH VALLEYS. THE WEDGE HOLDS FIRM MOST OF THE DAY SUN WHICH WILL KEEP THE BEST INSTABILITY SOUTH OF THE FCST AREA. HOWEVER...THE TMB LOOKS TO PUSH NORTH AFT 18Z...SO THE SRN ZONES COULD SEE SOME THUNDER WITH ROTATION ALONG THE BNDRY. THERE WILL BE PLENTY OF SHEAR...SO STRONG TO MAYBE SEVERE STORMS ARE POSSIBLE IN THE AFTERNOON ACROSS THE SRN ZONES. HOWEVER...THERE IS NOT ENOUGH CONFIDENCE IN THE INSTABILITY SETUP AT THIS TIME TO INCLUDE MENTION IN THE HWO. THERE WILL BE A GOOD AMOUNT OF RAIN WITH THIS SYSTEM SUN THROUGH SUN NIGHT...BUT THERE SHOULDN/T BE SIGFNT HYDRO ISSUES AS THE OVERALL SYSTEM REMAINS PROGRESSIVE. MANY PLACES WILL LIKELY SEE ARND AN INCH OF RAIN DURING THIS TIME PERIOD. MAX TEMPS ON SUN WILL BE TRICKY AS THE WEDGE BREAKS DOWN...BUT FOR NOW HAVE RIGHT AROUND OR A BIT ABOVE NORMAL FAR SOUTH TO ABOUT 5 DEGREES BELOW NORMAL NORTH. THE LOWER MTN VALLEYS WILL BE AROUND NORMAL...WITH THE NRN MTN VALLEYS A FEW DEGREES COOLER. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 300 AM FRIDAY...MOISTURE LEVELS BEGIN TO WANE EARLY MON WITH A DRY SLOT MIXING IN FROM THE SW. THE BEST DEEP LAYERED FORCING REMAINS NW OF THE AREA AND POPS WERE ADJ DOWN A BIT...HOWEVER THE NC MTNS COULD STILL SEE CHANCE POPS ESP ACROSS THE HIGHER TERRAIN WITH JUST ENOUGH MOISTURE AND A ROBUST H85 SW FLOW CONTINUING. THE SFC P/GRAD INCREASES MON WITH A COLD FRONT PUSHING EAST. THERE WILL BE THE A POTENTIAL FOR BETTER MIXING WITH THE DRIER AIR...THUS WINDS COULD BECOME FAIRLY GUSTY IN THE AFTERNOON. SFC WINDS DON/T SHIFT WNW/LY UNTIL LATE IN THE DAY...SO MAX TEMPS WILL LIKELY REACH A COUPLE CATS ABOVE NORMAL. VERY STRONG DYNAMICS REMAIN ALOFT TUE THROUGH WED...HOWEVER A RELATIVELY DRY PACIFIC SFC HIGH WILL MEANDER OVER THE DEEP SOUTH AND ACROSS THE CWFA. THIS WILL KEEP PRECIP CHANCES LOW WITH SOME -RA/SN ACTIVITY ACROSS THE NC MTNS EARLY TUE AND OVER THE HIGHER NC MTN TERRAIN WED ASSOCIATED WITH AN APPROACHING MOISTURE LIMITED CLIPPER LOW. MAX TEMPS TUE WILL BE RIGHT AROUND NORMAL...THEN A COOL DOWN TO ARND 5 DEGREES BELOW NORMAL WED AND THU AS ANOTHER LLVL THETA/E TROF FILTERS INTO THE REGION. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... AT KCLT AND ELSEWHERE...VFR WITH DEEP DRY AIR IN PLACE BENEATH HIGH PRESSURE MOVING FROM THE OHIO VALLEY TO THE MID-ATLANTIC COAST TODAY. A COUPLE UPPER DISTURBANCES WILL BRING ONLY CIRRUS. WITH FAST WESTERLY UPPER FLOW THIS MORNING...WIND DIRECTION WILL BE INFLUENCED BY A PRONOUNCED LEE TROUGH OVER NWRN NC...POSSIBLY PLACING SOME VARIABILITY INTO THE OTHERWISE NNW WINDS. WINDS CONTINUE TO VEER THRU NE THIS AFTN AND THEN TO NEARLY DUE E THIS EVENING...IF NOT GOING CALM. KAVL WILL LIKELY SEE WINDS CHANNELED TO SE AT THAT TIME. OUTLOOK...DRY HIGH PRESSURE LINGERS INTO SATURDAY. CLOUDS AND PRECIPITATION RETURN TO THE AREA ON SUNDAY WITH ANOTHER FRONT...AND ASSOCIATED RESTRICTIONS ARE POSSIBLE. BRIEF DRYING FOLLOWS THE FRONT ON MONDAY. CONFIDENCE TABLE... 16-22Z 22-04Z 04-10Z 10-12Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% 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 && .FIRE WEATHER... GIVEN THE DRY AIRMASS AND ABUNDANT INSOLATION TODAY...DEWPOINTS MAY LOCALLY MIX OUT APPRECIABLY. GIVEN FORECAST TEMPS THIS COULD RESULT IN ISOLATED AREAS SEEING RH DIP BELOW 20 PERCENT. WINDS WILL BE PRETTY LIGHT SO MAJOR FIRE WX CONCERNS ARE NOT ANTICIPATED. THIS ALSO IN LIGHT OF FUEL MOISTURES REMAINING A COUPLE PERCENT ABOVE CRITICAL LEVELS. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...CSH/SBK NEAR TERM...JOH/WIMBERLEY SHORT TERM...SBK LONG TERM...SBK AVIATION...WIMBERLEY FIRE WEATHER...

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