Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 210822
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
322 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/...
AS OF 300 AM EST...A POLAR AIRMASS WILL CONTINUE TO SPREAD INTO THE
AREA THIS MORNING BEHIND A WEAK COLD FRONT. DESPITE COLD ADVECTION
AND NW FLOW ALOFT...LIGHT SFC WINDS STILL FAVOR MORE WESTERLY OVER
THE SERN HALF OF THE CWFA. A TIGHT UPPER GRADIENT IS SEEN OVER THE
SRN APPALACHIANS ON THE BACK SIDE OF A BROAD TROUGH AND AS A RESULT
THERE IS A PRETTY PRONOUNCED LEE SFC TROUGH OVER NW NC. THE
ASSOCIATED WIND FIELD SEEMS TO BE INTERFERING WITH THE SFC COLD
ADVECTION THRU THE AREA. THE COLDER/DRIER AIRMASS MAY NOT REALLY
MAKE IT INTO THE UPSTATE UNTIL AFTER DAYBREAK...WHEN MIXING BEGINS.

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. VERY LITTLE MOISTURE IS SEEN ALOFT BUT A COUPLE OF
WEAK EMBEDDED DISTURBANCES MIGHT PRODUCE SOME CIRRUS. LOW LEVEL FLOW
WILL CONTINUE TO VEER THIS AFTN AND TONIGHT...PERHAPS BRINGING BACK
ENOUGH MOISTURE FOR PARTIAL MIDLEVEL CLOUDINESS LATE TONIGHT.
OVERALL THE WEATHER IN THE NEAR TERM WILL BE SETTLED EXCEPT FOR SOME
FAIRLY GUSTY WINDS THIS MORNING AND EARLY AFTN ON MTN RIDGES AS COLD
ADVECTION CONTINUES. 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 SEVERE STORMS ARE POSSIBLE IN THE AFTERNOON MAINLY SOUTH. 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 /09Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...VFR WITH DEEP DRY AIR IN PLACE. UPPER
DISTURBANCES WILL ONLY BRING A LITTLE CIRRUS THIS PERIOD. COLD
ADVECTION IS ALREADY OCCURRING ON NW WINDS ABOVE THE BDY LAYER...AND
A SFC COLD FRONT SHOULD PUSH THRU ALL SITES BY DAWN. WITH FAST
WESTERLY UPPER FLOW WIND DIRECTION WILL ALSO BE INFLUENCED BY A
PRONOUNCED LEE TROUGH OVER NWRN NC. FOR THIS REASON WINDS MAY NOT
REALLY FAVOR NW UNTIL AFTER MIXING DEEPENS WITH DIURNAL HEATING.
REFLECTED THIS AT KCLT AND KHKY OMITTING THE MORE NORTHERLY WINDS
UNTIL 12Z. SFC HIGH WILL SHIFT FROM THE OH VALLEY TO THE MID-
ATLANTIC TODAY WITH WINDS CONTINUING TO VEER THIS AFTN THEN GOING
NEARLY CALM THIS EVENING.

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...

            08-14Z        14-20Z        20-02Z        02-06Z
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

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...CSH/SBK
NEAR TERM...WIMBERLEY
SHORT TERM...SBK
LONG TERM...SBK
AVIATION...WIMBERLEY



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