-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 151449
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1049 AM EDT SAT JUN 15 2013

.SYNOPSIS...
DRY HIGH PRESSURE WILL SETTLE ACROSS THE REGION THROUGH THE WEEKEND.
A COLD FRONT WILL APPROACH THE AREA FROM THE NORTHWEST EARLY IN THE
WEEK AND THEN STALL ACROSS THE REGION THROUGH THE REMAINDER OF THE
WEEK...KEEPING CONDITIONS UNSETTLED.

&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 945 AM EDT SATURDAY...THE FORECAST GRIDS ARE IN GOOD SHAPE
THIS MORNING. THERE HAS BEEN AN INCREASE IN CLOUD COVER ALONG THE
IMMEDIATE TENNESSEE LINE SINCE SUNRISE. THERE APPEARS TO BE SOME
KIND OF WEAK BNDRY OR GRAVITY WAVE MOVING INTO THE MTNS...PROBABLY
THE REMNANT OF AN OLD OUTFLOW BNDRY. THIS WILL HELP TO ENHANCE CU
AND SOME MOUNTAIN WAVE CLOUDS OVER THE NEXT COUPLE HOURS. IT MAY
GENERATE SOME LLVL TURBULENCE AS WELL...SOMETHING FOR PILOTS TO NOTE.

AS OF 700 AM EDT...DEEP LAYER NW FLOW CONTINUES ALOFT OVER THE
REGION BETWEEN THE OFFSHORE TROUGH AXIS AND A RIDGE OVER THE CENTRAL
CONUS. A WEAK MCS IS DECAYING OVER MO THIS MORNING...AND A
FLATTENING UPPER LEVEL HEIGHT FIELD TODAY WILL PRODUCE MORE EASTWARD
MOVEMENT OF ANY SUBSEQUENT MCS WITH TIME. THE MAIN IMPACT OF THE
CONVECTION WILL BE THIN CIRRUS PUSHING INTO THE FORECAST AREA ON NW
FLOW ALOFT. THE ONLY OTHER CLOUDS WILL BE OCCASIONAL STRATOCUMULUS
UNDER A MID LEVEL INVERSION. THE AIRMASS WILL CONTINUE TO MODIFY
THROUGH TONIGHT AS 850 MB FLOW GRADUALLY BECOMES MORE SOUTHWESTERLY
OVER TIME. ANTICIPATE NEAR NORMAL MAX TEMPS THIS AFTN WITH HIGHS IN
THE 80S EXCEPT FOR HIGHER MTN 70S. MIN TEMPS WILL CREEP BACK ABOVE
NORMAL TONIGHT...WITH UPPER 50S MTNS TO MID 60S PIEDMONT.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM EDT SATURDAY...FLATTENING UPPER RIDGE AND EASTWARD
MIGRATING SURFACE HIGH WILL PROVIDE INCREASED CHANCES FOR
PRECIPITATION ON SUNDAY.  SOUTHERLY FLOW AT THE SURFACE CONTINUES TO
ADVECT AMPLE MOISTURE AS DEWPOINTS WILL BE IN THE MID TO UPPER 60S.
FORECAST SOUNDINGS CONTINUE TO INDICATE A FAIRLY SUBSTANTIAL CAPPING
INVERSION ACROSS  NORTHEAST GEORGIA...THE UPSTATE OF SOUTH
CAROLINA...AND THE MAJORITY OF WESTERN NORTH CAROLINA.  THE HIGHER
TERRAIN LOOKS TO HAVE THE GREATEST POTENTIAL FOR ANY SHOWER OR
THUNDERSTORM DEVELOPMENT AS MECHANICAL FORCING WILL AID IN EROSION
OF CAP.  NOT EXPECTING ANY OF THE DEVELOPMENT TO BE SEVERE IN NATURE
AS BOTH SBCAPE AND BULK SHEAR VALUES LOOK TOO LOW FOR ANY ORGANIZED
UPDRAFTS.  THUS...EXPECTING PULSE TYPE CONVECTION DURING THE PEAK
HEATING HOURS LEADING TO CHANCE POPS ACROSS THE HIGHER TERRAIN AND
SLIGHT CHANCE POPS ALONG AND NORTH OF THE I85 CORRIDOR FOR SUNDAY
AFTERNOON. TEMPERATURES ON SUNDAY WILL BE AT OR ABOVE NORMAL FOR
MOST AREAS.

BEYOND THAT...THE GFS GUIDANCE LOOKS TO HAVE SOME CONVECTIVE
FEEDBACK AS IT DEVELOPS A FAIRLY UNREALISTIC SUBSTANTIAL SURFACE LOW
ACROSS THE MID MISSISSIPPI RIVER VALLEY ON MONDAY.  THEREFORE LEANED
HEAVILY ON BOTH ECMWF AND HPC GUIDANCE THROUGH THE REMAINDER OF THE
FORECAST.  DUE TO INCREASING MOISTURE IN THE ATMOSPHERE...KEPT POPS
ELEVATED THROUGH MONDAY AND INTO TUESDAY AS A COLD FRONT
APPROACHES.  AS THE FRONT NEARS ON TUESDAY...IT LOOKS AS IF IT
REALLY LOSES ITS PUNCH...THUS STALLING ACROSS THE OHIO AND TENNESSEE
RIVER VALLEYS.  CONSIDERING CONVERGENCE ALONG THE STALLED BOUNDARY
AND DAYTIME HEATING ON TUESDAY AFTERNOON...INCREASED POPS TO LIKELY
LEVELS.  HOWEVER...SKY COVER ACROSS THE HIGHER TERRAIN AND INTO THE
FOOTHILLS COULD SUPPRESS BUILDING DIURNAL INSTABILITY SOMEWHAT
LEADING TO AREAS FURTHER EAST SEEING THE GREATEST POTENTIAL FOR
THUNDERSTORM DEVELOPMENT.  THE MAIN THREATS WITH ANY OF THESE
THUNDERSTORMS WILL BE GUSTY WINDS...SMALL HAIL...AND BRIEF HEAVY
RAINFALL.

TEMPERATURES ON MONDAY AND TUESDAY WILL BE SLIGHTLY COOLER AS THE
RIDGE BREAKS DOWN LEADING TO INCREASED SKY COVER.  THIS SKY COVER
COMBINED WITH ANY AFTERNOON CONVECTION WILL PLAY A VITAL ROLE ON
DAYTIME HIGH TEMPERATURES.  WENT WITH BELOW NORMAL HIGHS AND
SLIGHTLY ABOVE NORMAL LOWS.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 250 AM SATURDAY...THE EXTENDED PERIOD STARTS OF WITH A COLD
FRONT SLOWLY MIGRATING SOUTHWARD INTO THE MIDLANDS/LOW COUNTRY
WEDNESDAY MORNING.  POST FRONTAL STRATIFORM PRECIPITATION WILL KEEP
CHANCE POPS NECESSARY ACROSS THE REGION WITH THE NORTH AND SOUTH
CAROLINA PIEDMONTS SEEING THE GREATEST PRECIPITATION CHANCES DUE TO
BOUNDARY PROXIMITY.  BY THAT TIME THE FRONT WILL MOSTLY BE A
CONVERGENCE BOUNDARY IN NATURE AS TEMPERATURES/DEWPOINTS BEHIND THE
FRONT WILL NOT SUFFER MUCH.  HIGHS ON WEDNESDAY AND THURSDAY WILL
LIKELY BE JUST SLIGHTLY BELOW NORMAL.  FOR THE REMAINDER OF THE
EXTENDED PERIOD...LOOK FOR A GRADUAL WARMING TREND AND OCCASIONAL
PRECIPITATION CHANCES THAT WILL BE MOSTLY ASSOCIATED WITH DAYTIME
HEATING INDUCED CONVECTION.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
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AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL CONTINUE THROUGH THE
PERIOD WITH SFC HIGH PRESSURE IN PLACE OVER THE SE. A DECAYING MCS
OVER MO WILL CONTINUE TO SEND FEW TO SCT CIRRUS INTO THE TERMINAL
FORECAST AREA ON NW FLOW ALOFT. OTHERWISE...EXPECT FEW TO SCT HIGH
BASED STRATOCUMULUS UNDER A MID LEVEL INVERSION. ANY FOG CHANCES
THIS MORNING APPEAR BEST IN THE SW NC MTN VALLEYS...AWAY FROM THE
TAF LOCATIONS...BUT TEMPO MVFR FOG MAY BE NEEDED AT KAVL. LIGHT AND
VARIABLE WINDS THIS MORNING WILL BECOME MORE SW THROUGH THE
DAY...BUT LIGHT WINDS THROUGH THE MIXED LAYER SHOULD PRODUCE NOTHING
HIGHER THAN 6 KT OF SFC WIND. MVFR TO IFR FOG WILL BE POSSIBLE IN
THE MTN VALLEYS LATE TONIGHT.

OUTLOOK...MOISTURE WILL SLOWLY RETURN THROUGH SUNDAY UNDER LIGHT S
TO SW FLOW AROUND BERMUDA HIGH PRESSURE...BUT WITH MAINLY VFR
CONDITIONS PERSISTING. THE CHANCES FOR SHRA/TSTMS AND ASSOCIATED
FLIGHT RESTRICTIONS WILL INCREASE MON THROUGH TUE WITH THE ARRIVAL
OF A FRONT AND LINGER THROUGH AT LEAST MID WEEK.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-14Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  88%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  93%

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
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&&

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

&&

$$
SYNOPSIS...HG
NEAR TERM...MCAVOY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG