Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 201041
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
641 AM EDT WED MAY 20 2015

.SYNOPSIS...
DRY HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY. BRIEFLY
UNSETTLED WEATHER WILL RETURN FROM THE WEST LATE TONIGHT INTO
THURSDAY WITH A PASSING COLD FRONT. DRIER CANADIAN HIGH PRESSURE
WILL BUILD OVER THE CAROLINAS AND NORTHEAST GEORGIA FRIDAY AND
REMAIN THROUGH THE WEEKEND. SOUTHERLY FLOW MOISTURE AROUND BERMUDA
HIGH PRESSURE WILL GRADUALLY RETURN EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 635 AM...FCST APPEARS TO BE ON TRACK...SO NO SIGNIFICANT
CHANGES AT THIS TIME.

A COLD FRONT HAS NOW SAGGED INTO THE UPSTATE AND MAY MAKE SLIGHTLY
FURTHER PROGRESS BEFORE STALLING OUT ACRS MIDDLE GA AND SRN SC LATER
TODAY. NEARLY ZONAL UPPER FLOW WILL BE PRESENT ALOFT. THE
ATMOSPHERIC COLUMN WILL BE QUITE A BIT DRIER OVER OUR AREA THAN IT
HAS BEEN OF LATE...AND THOUGH LAPSE RATES REMAIN AT LEAST MARGINALLY
SUPPORTIVE OF CONVECTION...THIS IS EXPECTED TO REMAIN ISOLATED AND
GENERALLY ALONG OR SOUTH OF THE NC BORDER WHERE DEWPTS WILL BE
HIGHEST. THAT SAID ANY STORMS THAT DO FORM MIGHT BE CAPABLE OF
STRONG WIND GUSTS GIVEN DRIER PROFILES. MOSTLY SUNNY SKIES ARE
ANTICIPATED...AND WITH THICKNESSES HAVING TAKEN ONLY A SLIGHT HIT
DUE TO THE FRONT...TEMPS AGAIN SHOULD PEAK SEVERAL DEGREES ABOVE
CLIMO. HUMIDITY WILL BE A BIT MORE COMFORTABLE HOWEVER.

MEANWHILE...A SHORTWAVE WILL MOVE OUT OF THE PLAINS AND INTO THE
OH/TN VALLEYS BY 00Z. AHEAD OF THIS FEATURE A WEAK SFC WAVE WILL
DEVELOP ALONG WHAT AMOUNTS TO A SECONDARY COLD FRONT SAGGING SWD. AS
THE SFC WAVE MOVES INTO OUR AREA THIS EVENING IT WILL GENERATE SOME
ISENTROPIC LIFT AND BRING SOME MOISTURE BACK OVER THE OLD FRONT.
ALSO...SOME ELEVATED CONVECTION COULD BE KICKED OFF. POPS WILL
INCREASE ACRS THE AREA FROM WEST TO EAST OVERNIGHT...WITH THE BEST
CHANCES IN THE MTNS...AND NRN FOOTHILLS/PIEDMONT. MIN TEMPS WILL
REMAIN SEVERAL DEGREES ABOVE NORMAL UNDER CLOUD COVER.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM EDT WED...BROAD HEIGHT FALLS WILL OCCUR ACROSS THE EAST
THU INTO THU NIGHT AS A TROUGH EXTENDING SOUTHWARD FROM QUEBEC
BOTTOMS OUT ACROSS THE CAROLINAS. PROFILES WILL BE FAIRLY DRY UNDER
THIS TROUGH...BUT SOME DEGREE OF SFC TO 850 MB MOISTURE WILL
ACCOMPANY A PASSING FRONTAL ZONE EARLY THU. THE BEST FORCING AND
MOISTURE FOR SCATTERED SHOWERS WILL OCCUR THU MORNING ACROSS THE NRN
TIER...WITH THE BETTER INSTABILITY FOR ANY AFTN AND EVENING SHOWERS
AND THUNDERSTORMS SHUNTED WELL TO THE EAST ACROSS THE COASTAL PLAIN.
MAXES WILL HOVER NEAR CLIMO IN THE MTNS THU AFTN...AND ABOUT A
CATEGORY OR SO ABOVE TO THE EAST. EXPECT ANY RESIDUAL UPSLOPE
SHOWERS TO QUICKLY DISSIPATE IN THE WRN MTNS THU NIGHT...WITH COOLER
TEMPERATURES SETTLING IN TO PRODUCE PLENTY OF 40S MTNS TO 50S
PIEDMONT.

HEIGHTS WILL BEGIN RISING AGAIN FROM THE WEST ON FRIDAY. DRY
PROFILES WILL BE IN PLACE...WITH MAX TEMPS FALLING ABOUT 5 DEGREES
BELOW CLIMO DURING A COMFORTABLE FRIDAY AFTERNOON.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 245 AM EDT WED...A DOMINANT RIDGE WILL SET UP OVER THE
SOUTHEAST THROUGH THE WEEKEND. IN ADDITION...SFC HIGH PRESSURE
BUILDING SWD FROM CANADA ON SAT WILL SEND A WEAK BACKDOOR COLD FRONT
INTO THE REGION WITH LITTLE OR NO ATTENDANT MOISTURE. ANY DEEPER
MOISTURE WILL GENERALLY STAY W OF THE SRN APPALACHIANS THROUGH THE
WEEKEND...BUT WITH A LOW LEVEL ATLANTIC FETCH GRADUALLY MODERATING
THE CP AIRMASS IN PLACE. ISOLD DIURNAL SHOWERS WILL BE POSSIBLE IN
THE SRN MOUNTAINS LATE SUNDAY...WITH TEMPERATURES WARMING BACK ABOVE
CLIMO.

THE RIDGE AXIS WILL MIGRATE OFFSHORE EARLY NEXT WEEK...BUT WITH ANY
PHASING TROUGHS TO THE WEST LIFTING MAINLY N OF THE OH VALLEY
THROUGH TUE. MOISTURE WILL CONTINUE TO GRADUALLY CREEP
EASTWARD...CAUSING DIURNAL CONVECTIVE CHANCES TO INCREASE MON AND
TUE AFTN...ESPECIALLY ACROSS THE MTNS. MAX TEMPS WILL WARM BACK
THROUGH THE 80S...WITH TEMPERATURES POSSIBLY APPROACHING 90 IN THE
PIEDMONT BY TUE AFTN.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR THROUGH AT LEAST THIS EVENING. LOOKS LIKE DRIER AIR
ARRIVING IN THE WAKE OF A COLD FRONT WILL BE UNSUPPORTIVE OF DEEP
CONVECTION TODAY...SO JUST EXPECTING A FEW HIGH BASED CU TO BREAK
OUT. WINDS WILL SHIFT FROM NE TO SE IN THE AFTN. TONIGHT...A WEAK
AREA OF LOW PRESSURE PASSING ALONG A SECONDARY COLD FRONT WILL BRING
AN INITIALLY VFR/MIDLEVEL CIG. LOW LEVEL MOIST UPGLIDE AHEAD OF THE
LOW STANDS A GOOD CHANCE OF CREATING MVFR OR EVEN IFR STRATUS CIGS
NEAR DAWN. THERE IS ALSO AN OUTSIDE CHANCE OF A SHOWER WHICH WILL
NOT BE MENTIONED AT THIS ISSUANCE...BUT SOME VSBY RESTRICTIONS COULD
RESULT IF SUCH SHOWERS PASSED OVERHEAD.

ELSEWHERE...COLD FRONT NOW OVER UPSTATE SC IS EXPECTED TO PUSH A BIT
FURTHER SOUTH THIS MORNING BEFORE STALLING ACRS THE MIDLANDS.
CONVECTION IS EXPECTED TO REMAIN ISOLATED TODAY IN THE DRIER AIRMASS
NORTH OF THIS FRONT. CHANCES AT THE SITES ARE LOW ENOUGH TO OMIT BUT
KGSP/KGMU APPEAR TO HAVE THE BEST SHOT. WINDS WILL VEER TO SE THIS
AFTN...EXCEPT AT KAVL WHICH IS MORE LIKELY TO REMAIN NW. INCREASING
CLOUDS CAN BE EXPECTED THIS EVENING AS AN INCOMING SFC LOW BRINGS
MOIST SOUTHERLY FLOW ALOFT. MVFR CIGS EXPECTED TO DEVELOP NEAR
DAYBREAK THU ALONG/NORTH OF I-40...INCLUDING AT KHKY. PRECIP CHANCES
INCREASE THROUGHOUT THE AREA BUT STILL REMAIN TOO LOW TO MENTION
THIS FAR OUT.

OUTLOOK...WAVE OF LOW PRESSURE WILL CROSS THE AREA THU...AND PRECIP
CHANCES DIMINISH BY THU NIGHT. HIGH PRESSURE BUILDS OVER THE
SOUTHEAST AND DRY WX RETURNS FOR THE UPCOMING WEEKEND...LIKELY
LASTING INTO EARLY NEXT WEEK.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  91%     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  91%     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...HG
NEAR TERM...WIMBERLEY
SHORT TERM...HG
LONG TERM...HG
AVIATION...WIMBERLEY



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