Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 251803
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
203 PM EDT FRI JUL 25 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ACROSS THE AREA THROUGH THE WEEKEND.
ANOTHER COLD FRONT IS EXPECTED TO REACH THE AREA FROM THE NORTHWEST
BY EARLY MONDAY. HIGH PRESSURE WILL REGAIN CONTROL ON TUESDAY...
LASTING THROUGH AT LEAST MID-WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
THE AFTERNOON CU FIELD IS LOOKING A LITTLE LESS AGITATED THAN IT DID
EVEN A COUPLE OF HOURS AGO. NEVERTHELESS...IT IS QUITE EXTENSIVE
ACROSS THE AREA...AND THE CURRENT VERTICAL DEVELOPMENT ALONG THE
BLUE RIDGE STILL HOLDS OUT SOME POTENTIAL FOR ISOLATED/WIDELY
SCATTERED DEEP CONVECTION TO DEVELOP THIS AFTERNOON...AND SLIGHT/LOW
CHANCE POPS WILL BE MAINTAINED THERE. MEANWHILE...DEEP CONVECTION IS
FIRING JUST SOUTH OF THE AREA IN THE VICINITY OF THE FRONTAL
BOUNDARY. OUTFLOW EMANATING FROM THIS ACTIVITY COULD STILL CAUSE A
FEW CELLS TO DEVELOP ACROSS OUR LOWER PIEDMONT AREAS THIS
AFTERNOON... SO A STRIPE OF SLIGHT CHANCE WILL BE MAINTAINED ACROSS
OUR SOUTHERN BORDER AS WELL.

OTHERWISE...CONVECTION SHOULD DIMINISH FAIRLY QUICKLY THIS EVENING.
LOW LEVEL MOISTURE REMAINS SUFFICIENT FOR DEVELOPMENT OF VALLEY FOG
AND LOW STRATUS LATE TONIGHT/EARLY SATURDAY. THERE COULD BE ANOTHER
ROUND OF LOW STRATUS OUTSIDE THE MTNS...ALTHOUGH VEERING LOW LEVEL
FLOW MAKES THAT LESS OF POSSIBILITY SAT MORNING. MIN TEMPS SHOULD
SETTLE VERY CLOSE TO CLIMO.

SATURDAY...FORECAST SOUNDINGS ARE CAPPED UNDER THE INFLUENCE OF
RISING HEIGHTS ALOFT...AS RIDGE AXIS ASSOCIATED WITH THE
SUB-TROPICAL HIGH OVER THE GREAT PLAINS NOSES ITS WAY TOWARD THE
SOUTHEAST COAST. AS A RESULT...THERE IS LITTLE TO NO MODEL QPF
RESPONSE ACROSS THE AREA SATURDAY AFTERNOON...AND A DRY FORECAST
WILL BE MAINTAINED AS INHERITED. OTHERWISE...TEMPS WILL WARM
NOTICEABLY FROM TODAY/S READINGS...WITH MAXES EXPECTED TO REACH THE
LOWER 90S IS MOST LOCATIONS EAST OF THE MTNS...AND MID/UPPER 80S
EXPECTED IN THE MTN VALLEYS.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 AM EDT FRIDAY...THE SHORT TERM PERIOD INITIALIZES SATURDAY
MORNING WITH REMNANT FRONT WELL TO THE SOUTHEAST ALONG THE
CAROLINA/GEORGIA COASTLINE.  SURFACE HIGH PRESSURE WILL QUICKLY
BUILD UNDER RISING HEIGHTS ALOFT.  DESPITE WEAK LEE TROF DEVELOPING
JUST EAST OF THE FORECAST AREA POTENTIALLY PROVIDING A FOCUS FOR
AFTERNOON CONVECTION...SOUNDINGS INDICATE A SUBSTANTIAL LOW/MID
LEVEL CAP IN PLACE.  NOT EXPECTING ANY POTENTIAL UPDRAFTS TO BREAK
THROUGH THE DEEP INHIBITION THEREFORE KEPT THE FORECAST DRY FOR
SATURDAY.

ALSO KEPT FORECAST DRY THROUGH SUNDAY MORNING AS UPPER HEIGHTS ARE
SLOW TO FALL DUE TO APPROACHING UPPER TROF AND ASSOCIATED SURFACE
COLD FRONT.  STILL THINK AREA OF GREATEST LIFT AND LOWEST INHIBITION
WILL REMAIN TIED TO LEE TROF REDEVELOPMENT EAST OF THE I77 CORRIDOR
THEREFORE CONTINUE WITH DRY FORECAST FOR THE PIEDMONT REGION THROUGH
THE AFTERNOON.  FURTHER WEST...HEIGHTS WILL BEGIN TO FALL RAPIDLY AS
UPPER SHORT WAVE AND ASSOCIATED MOISTURE ADVECT INTO THE
CENTRAL/SOUTHERN APPS.  MODELS TEND TO AGREE ON AT LEAST SOME
PRECIPITATION PUSHING INTO THE NORTHERN MOUNTAINS BY MID/LATE
AFTERNOON ON SUNDAY...WITH CHANCES INCREASING AHEAD OF THE
APPROACHING FRONT THROUGH THE OVERNIGHT.  THEREFORE...SOLID CHANCE
POPS ARE FEATURED SUNDAY EVENING ALONG THE HIGHER TERRAIN OF NC
INCREASING TO NEAR LIKELY POPS BY MONDAY MORNING NEAR THE TN
BORDER.  ELSEWHERE POPS TAPER DOWN SHARPLY TO SLIGHT CHANCE LEVELS
OVER THE NC/SC FOOTHILLS AND WESTERN MOST AREAS OF THE PIEDMONT.
TEMPERATURES THROUGH THE SHORT TERM PERIOD WILL GRADUALLY WARM AS
SOUTHERLY FLOW RAMPS UP AHEAD OF APPROACHING SURFACE TROF.
EXPECTING HIGHS ON BOTH SATURDAY AND SUNDAY TO SURGE TO ABOVE NORMAL
LEVELS WITH MID 90S POSSIBLE FOR SOUTHERN PORTIONS OF THE FORECAST
AREA ON SUNDAY.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 AM EDT FRIDAY...THE EXTENDED RANGE PERIOD WILL BEGIN WITH
A RATHER ACTIVE PATTERN ON MONDAY MORNING.  STRONG HEIGHT FALLS WILL
BE ADVECTING IN FROM THE WEST AS A COLD FRONT STRETCHES ALONG THE
APPALACHIAN CHAIN FROM A PARENT SURFACE CYCLONE ACROSS THE EASTERN
GREAT LAKES.  POPS WILL INITIALIZE AT HIGH END CHANCE LEVELS ACROSS
THE HIGHER TERRAIN AS THE PRE-FRONTAL ACTIVITY PUSHES INTO THE REGION
AROUND OR JUST BEFORE DAYBREAK MONDAY.  THE ENTIRE COMPLEX WILL
CONTINUE ADVECTING EAST THROUGH THE MORNING AND EARLY AFTERNOON
HOURS ALLOWING FOR SOME DIURNAL DESTABILIZATION AHEAD ACROSS THE
NC/SC PIEDMONT REGIONS.  THERE IS STILL SOME UNCERTAINTY REGARDING
OVERALL MAGNITUDE OF INSTABILITY THAT WILL BUILD AHEAD OF THE FRONT
AS ABUNDANT SKY COVER WILL WORK TO LIMIT HEATING.  THAT
SAID...MODEST WARM SECTOR ALREADY IN PLACE WILL NOT NEED MUCH
HEATING FOR LAPSE RATES TO SUPPORT SUBSTANTIAL LOW LEVEL LIFT.
ALOFT DRIER AIR WILL BE ADVECTING IN AS STRONG WNW FLOW ASSOCIATED
WITH TROF AXIS PUSHES INTO THE REGION.  THIS WILL ALLOW MID LEVEL
LAPSE RATES TO STEEPEN...POTENTIALLY LEADING TO A FAIRLY UNSTABLE
PROFILE.  SPEAKING OF...LATEST GFS FORECAST SOUNDINGS INDICATE
NEARLY 1500J/KG SBCAPE AND LONG STRAIGHT HODOGRAPHS PRODUCING DEEP
LAYER SHEAR IN EXCESS OF 35KTS SUGGESTING MULTICELL STRONG/SEVERE
THUNDERSTORMS. ALL THAT SAID...THERE IS STILL PLENTY OF TIME FOR THE
PATTERN TO CHANGE SLIGHTLY WHICH COULD SUBSTANTIALLY ALTER THE
OUTCOME.  THUS...DUE TO RANGE IN THE FORECAST...KEPT POPS CAPPED AT
CHANCE LEVELS FOR THE ENTIRE REGION ON MONDAY AFTERNOON.

SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION BEHIND THE FRONT
FOR TUESDAY AND WEDNESDAY LEADING TO LOWER PRECIPITATION CHANCES
DESPITE PERSISTENT UPPER TROF REMAINING NEARLY STATIONARY.  FORECAST
WILL FEATURE SLIGHT CHANCE POPS ACROSS THE HIGH TERRAIN THROUGH
WEDNESDAY MORNING AMIDST STRONG NW FLOW.  THE SURFACE RIDGE REMAINS
DOMINATE THROUGH THE REMAINDER OF THE PERIOD AS IT REPOSITIONS
ITSELF TO THE NORTHEAST AND EXTENDS IN A WEDGE LIKE PATTERN ALONG
THE LEE SIDE OF THE APPALACHIANS BY THURSDAY.  SURFACE FLOW WILL
SHIFT TO MORE OF AN EAST TO SOUTHEAST COMPONENT LEADING TO POTENTIAL
UPSLOPE/UPGLIDE PRECIPITATION INTO FRIDAY.  THUS CHANCE LEVEL POPS
ARE ONCE AGAIN FEATURED THROUGH THE REMAINDER OF THE FORECAST ALONG
THE HIGH TERRAIN WITH SLIGHT CHANCE POPS HIGHLIGHTED ELSEWHERE.
TEMPERATURES WILL GRADUALLY COOL BEHIND THE FROPA ON MONDAY WITH
HIGHS TOPPING OUT NEARLY A CATEGORY BELOW NORMAL BY THURSDAY FOR
SOME LOCATIONS.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE (EXCEPT KAVL)...A RATHER EXTENSIVE MVFR/LOW
VFR CU FIELD HAS DEVELOPED ACROSS THE AREA THIS AFTERNOON...AND MANY
LOCATIONS WILL SEE PERIODS OF BKN CLOUDS IN THE 025-035 RANGE...ESP
THROUGH 20 OR 21Z. A FEW SHOWERS/STORMS MAY DEVELOP ACROSS THE
MTNS...AND FARTHER SOUTH NEARER THE SOUTH CAROLINA MIDLANDS...BUT
CONVECTION SHOULD STAY AWAY FROM THE TERMINALS. WINDS THIS AFTERNOON
WILL LIKELY VARY FROM E/NE TO E/SE...BUT SPEEDS SHOULD REMAIN LESS
THAN 5 KTS. WITH LOW LEVEL MOISTURE REMAINING IN ABUNDANCE...THERE
IS A CHANCE FOR BR AND POSSIBLY A RETURN OF LOW STRATUS TOWARD
DAYBREAK SATURDAY. HOWEVER...WITH LOW LEVEL FLOW EXPECTED TO VEER
TOWARD THE SW...THE PROBABILITY OF LOW CLOUDS DEVELOPING APPEARS
QUITE A BIT LOWER THAN WHAT WAS SEEN THIS MORNING...SO VFR SKY
CONDITIONS WILL BE MAINTAINED.

AT KAVL...CANNOT RULE OUT A SHOWER OR THUNDERSTORM PASSING NEAR THE
TERMINAL THIS AFTERNOON...BUT COVERAGE SHOULD BE TOO LIMITED TO
WARRANT A VCTS/VCSH MENTION. OTHERWISE...PERIODS OF LOW VFR CIGS CAN
BE EXPECTED THROUGH THE AFTERNOON. PLENTIFUL LOW LEVEL MOISTURE
MEANS FOG AND PERHAPS LOW STRATUS ARE A GOOD BET TONIGHT...AND HAVE
STARTED THINGS OFF WITH A 3SM/SCT004 MENTION AFTER 06Z.

OUTLOOK...GENERALLY VFR THROUGH SUNDAY MORNING...EXCEPT FOR POSSIBLY
MORNING MTN VALLEY FOG. SCT THUNDERSTORMS MAY RETURN TO THE FORECAST
AREA FOR SUNDAY AFTERNOON THROUGH MON...AS ANOTHER COLD FRONT
APPROACHES AND THEN MOVES THROUGH THE AREA BY MON NIGHT. VFR
CONDITIONS WILL THEN LINGER THROUGH MID-WEEK.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       MED   72%     HIGH  86%     HIGH  86%     HIGH  84%
KGSP       MED   65%     HIGH  84%     HIGH  90%     HIGH  91%
KAVL       MED   68%     MED   66%     MED   66%     HIGH  81%
KHKY       MED   67%     HIGH  87%     MED   79%     MED   72%
KGMU       HIGH  85%     HIGH  94%     HIGH  93%     HIGH  98%
KAND       HIGH 100%     HIGH 100%     HIGH  96%     HIGH  98%

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...JDL
NEAR TERM...JDL
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...JDL





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