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Local forecast by
"City, St"
  
000
FXUS62 KGSP 021050
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
650 AM EDT TUE SEP 2 2014

.SYNOPSIS...
CONTINUED SOUTHERLY FLOW AROUND A BERMUDA HIGH WILL PROVIDE MOISTURE 
FOR DIURNAL SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING 
AHEAD OF A WEAK COLD FRONT THAT WILL PUSH THROUGH THE REGION 
OVERNIGHT.  THIS FRONT WILL HAVE LITTLE TO NO EFFECT IN REDUCING 
PRECIPITATION CHANCES ACROSS THE REGION FOR WEDNESDAY AND THROUGH 
THE REST OF THE WORK WEEK AS ABOVE MENTIONED BERMUDA HIGH REGAINS 
CONTROL LEADING TO CONTINUED AFTERNOON CONVECTION CHANCES.  ANOTHER 
COLD FRONT WILL SWEEP THROUGH THE REGION OVER THE WEEKEND PROVIDING 
AN ADDITIONAL FOCUS FOR THUNDERSTORMS ON SATURDAY AND SUNDAY.  
BUILDING HIGH PRESSURE WILL HIGHLIGHT THE WEATHER PATTERN FOR THE 
START OF THE NEXT WORK WEEK LEADING TO COOLER TEMPERATURES AND MORE 
STABLE WEATHER.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 650 AM...FOG AND LOW CLOUDS HAVE BEEN MORE PATCHY THAN 
EXPECTED ACROSS THE MTN VALLEYS AND MORE ISOLATED ELSEWHERE. 
OTHERWISE...FCST REMAINS ON TRACK WITH MOSTLY CLEAR SKIES AND LIGHT 
WINDS THIS MORNING THEN STRONGER WINDS WITH INCREASING CLOUDS FOR 
THE AFTERNOON AND INCREASING CHC OF CONVECTION.

AS OF 320 AM...AREAS OF DENSE MTN VALLEY FOG...AND PATCHY DENSE FOG 
ELSEWHERE...SHUD DISSIPATE QUICKLY THIS MORNING WITH MOSTLY CLEAR 
SKIES IN PLACE. UPPER RIDGE ACROSS THE SERN CONUS IS SUPPRESSED 
TODAY AND TONIGHT AS SHORT WAVES MOVE ACROSS THE AREA IN THE 
DEVELOPING WLY FLOW. AT THE SFC...A WEAK COLD FRONT MOVES INTO THE 
AREA LATE THIS AFTERNOON OR THIS EVENING AND STALLS. MODERATE 
INSTABILITY DEVELOPS OVER THE AREA WITH GOOD HEATING AND COPIOUS LOW 
LEVEL MOISTURE. WITH THE INCREASED FORCING AND STRONGER 
INSTABILITY...THE GUIDANCE IS SUGGESTING BETTER CONVECTIVE COVERAGE 
TODAY ACROSS THE BOARD. ALTHOUGH...COVERAGE IS STILL EXPECTED TO BE 
HIGHER ACROSS THE MTNS WHERE THE FORCING IS BETTER. IN FACT... 
ISOLATED SEVERE STORMS WILL BE MORE LIKELY TODAY AS SHEAR...THOUGH 
NOT STRONG...DOES INCREASE. DCAPE AND SFC DELTA THETA-E VALUES WILL 
BE ON THE INCREASE AS WELL. CONVECTION MAY LINGER LONGER THRU THE 
EVENING...AND POSSIBLY INTO THE EARLY OVERNIGHT HOURS GIVEN THE 
STALLED BOUNDARY. HIGHS WILL BE WELL ABOVE NORMAL ONCE AGAIN WITH 
HEAT INDEX VALUES NEAR 100 ACROSS THE SERN CWFA. LOWS TONIGHT ALSO 
CONTINUE WELL ABOVE NORMAL...WITH ANOTHER NIGHT OF DENSE MTN VALLEY 
FOG LIKELY.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT TUESDAY...THE SHORT TERM PERIOD INITIALIZES 
WEDNESDAY MORNING WITH ELONGATED UPPER RIDGE CENTERED OVER THE DEEP 
SOUTH AND PERSISTENT BERMUDA HIGH DOMINATING LOW LEVEL FLOW.  CLOSER 
TO HOME...REMNANT COLD FRONTAL BOUNDARY WILL BE PUSHING INTO THE 
SOUTHERN TIER OF THE FORECAST AREA AS HIGH PRESSURE BUILDS TO THE 
NORTH.  CONVECTION WILL LIKELY BE LIMITED EARLY ON WEDNESDAY AS THE 
FRONT SLOWS WITH LITTLE FORCING IN THE REGION.  MODELS INDICATE 
BUILDING INSTABILITY DURING THE AFTERNOON WITH THE FRONTAL MOISTURE 
AXIS DISSECTING THE FORECAST AREA LEADING TO ENHANCED INSTABILITY 
ACROSS THE UPSTATE AND PORTIONS OF NORTHEAST GA AND THE SOUTHWEST NC 
MOUNTAINS...DECREASING TO THE NORTH.  FORECAST WILL FEATURE 
INCREASING DIURNAL POPS WITH SCATTERED/NUMEROUS SHOWERS AND 
THUNDERSTORMS ACROSS THE SOUTHWEST MOUNTAINS WHILE 
ISOLATED/SCATTERED CONVECTION IS FORECAST ELSEWHERE.  AS STATED 
ABOVE...PROFILES WILL FEATURE STEEP LAPSE RATES LEADING TO MODERATE 
INSTABILITY POSSIBLY SUPPORTIVE OF STRONG/SEVERE CONVECTION WITH 
DOWNBURST WINDS AND HAIL BEING PRIMARY THREATS.  

AS HIGH PRESSURE SLIDES BY TO THE NORTH...BERMUDA HIGH WILL LIKELY 
REGAIN CONTROL LEADING TO PREDOMINATE SOUTHERLY FLOW.  AS A 
CONSEQUENCE...LINGERING SEMI STALLED MOISTURE AXIS WILL SLOWLY 
MIGRATE NORTHWARD AS A WARM FRONT ACROSS THE FORECAST AREA ON 
THURSDAY.  POPS ON THURSDAY WILL ONCE AGAIN INCREASE DIURNALLY AS 
PROFILES DESTABILIZE LEADING TO SCATTERED/NUMEROUS SHOWERS AND 
THUNDERSTORMS REGIONWIDE WITH THE BEST CHANCES ONCE AGAIN RESIDING 
ALONG THE HIGH TERRAIN.  THAT SAID...CONVECTION WILL LIKELY BE MOST 
ENHANCED ALONG AND NEAR WARM FRONTAL AXIS AS IT SWEEPS NORTHWARD 
THROUGH THE REGION.  PROFILES WILL RESEMBLE THAT OF WEDNESDAY WITH 
LOW LEVEL HEATING LEADING TO STEEPENING LAPSE RATES AND NEARLY 
1500J/KG SBCAPE WITH MINIMAL SHEAR.  TEMPERATURES THROUGH THE SHORT 
TERM PERIOD WILL REMAIN AT OR JUST ABOVE NORMAL LEVELS DESPITE WEAK 
COLD FROPA AT FORECAST INITIATION.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...LONG RANGE MODELS REMAIN IN AGREEMENT 
WITH THE OVERALL PATTERN THROUGH THE EXTENDED RANGE PERIOD WHICH 
INITIALIZES ON FRIDAY MORNING WITH DEEP LAYER RIDING IN CONTROL 
ACROSS THE SOUTHEAST.  UPPER TROF PUSHING THROUGH CENTRAL ONTARIO 
WILL HAVE SPREAD A COLD FRONT SOUTHWARD THROUGH THE GREAT LAKES 
REGION...WESTWARD THROUGH THE MID MISSISSIPPI RIVER VALLEY.  
CONTINUED SOUTHERLY FLOW INTO THE WEEKEND WILL LEAD TO DIURNAL 
CONVECTIVE CHANCES WITH SOLID CHANCE POPS FORECAST ON FRIDAY AND 
SATURDAY AHEAD OF APPROACHING FRONT.  ABOVE MENTIONED COLD FRONT IS 
PROGGED TO ENTER THE MOUNTAINS SATURDAY EVENING WITH GRADUAL SLOWING 
LIKELY DURING THE OVERNIGHT.  THUS THE FORECAST WILL FEATURE LIKELY 
LEVEL POPS OVER THE HIGH TERRAIN ON SATURDAY EVENING WITH SOLID 
CHANCE POPS ACROSS NORTHEAST GA AND THE NC/SC PIEDMONT.  FRONTAL 
BOUNDARY WILL CONTINUE SLOWED FORWARD PROPAGATION THROUGH THE REST 
OF THE FORECAST AREA ON SUNDAY LEADING TO PERSISTENT CHANCE LEVEL 
POPS WITH POSSIBLE SHORTWAVE ENHANCEMENT ACROSS THE NORTH.  HIGH 
PRESSURE WILL SPILL INTO THE REGION TAKING ON A WEAK EARLY 
METEOROLOGICAL FALL WEDGE CONFIGURATION ON MONDAY...LASTING INTO 
WEDNESDAY.  EXPECTING LOWERED PRECIPITATION CHANCES COINCIDING WITH 
COOLER BELOW NORMAL TEMPERATURES THROUGH MIDWEEK BEFORE DEEP LAYER 
SOUTHEAST RIDGING RESUMES LEADING TO MODERATING TEMPERATURES.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AT KCLT...THIN HIGH CLOUDS AND LIGHT SLY WIND THIS MORNING WILL GIVE 
WAY TO DEVELOPING HIGH BASED CU AND SWLY WINDS FOR THE EARLY 
AFTERNOON. THE CU BECOMES BKN BY LATE AFTERNOON WITH CONTINUED SWLY 
WINDS. SHORTWAVES MOVING INTO WESTERN NC FROM THE NW LATE DAY COULD 
ALLOW TSRA TO MAKE A RUN TOWARD THE PIEDMONT AGAIN...AND PROB30 FOR 
TSRA AFTER 21Z AND INTO THE EVENING APPEARS WARRANTED. BKN HIGH 
BASED CU LINGERS INTO THE OVERNIGHT WITH LIGHT SLY WINDS. FOR NOW... 
DO NOT EXPECT ANY VSBY RESTRICTIONS OVERNIGHT...BUT THAT COULD 
CHANGE IF RAIN DOES FALL AT THE AIRFIELD AND SKIES CLEAR.

ELSEWHERE...CIGS AND VSBY RESTRICTIONS HAVE BEEN TEMPO AND VARIABLE 
AT KAVL THIS MORNING. STILL A CHANCE FOR A RESTRICTION UNTIL SHORTLY 
AFTER DAYBREAK. OTHERWISE...THIN HIGH CLOUDS AND LIGHT SWLY WIND 
THIS MORNING WILL GIVE WAY TO DEVELOPING HIGH BASED CU AND STRONGER 
SWLY WINDS FOR THE EARLY AFTERNOON. KAVL WILL SEE CONTINUED NWLY 
WINDS. PROB30 FOR TSRA APPEARS WARRANTED AT ALL LOCATIONS FOR LATE 
AFTERNOON INTO THE EVENING. VCTS INCLUDED FOR EARLY AFTERNOON AT 
KAVL. SHOULD BE ANOTHER ROUND OF VSBY AND CIG RESTRICTIONS AT KAVL 
OVERNIGHT. HOWEVER...HAVE LIMITED TO MVFR VSBY AND IFR CIGS FOR 
NOW...BUT THE COULD BE WORSE. ELSEWHERE...DO NOT EXPECT ANY VSBY 
RESTRICTIONS OVERNIGHT...BUT THAT COULD CHANGE IF RAIN DOES FALL AT 
THE AIRFIELDS AND SKIES CLEAR.

OUTLOOK...GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF 
THE WEEK...BUT RESTRICTIONS ARE LIKELY EARLY EACH MORNING IN THE 
MOUNTAIN VALLEYS DUE TO LOW CLOUDS AND FOG. DIURNALLY DRIVEN 
SHRA/TSRA ARE EXPECTED EACH AFTERNOON AND EARLY EVENING...WITH THE 
MOST COVERAGE OVER THE MOUNTAINS.

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-11Z 
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%     
KAVL       MED   78%     HIGH  99%     HIGH 100%     HIGH  80%     
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%     
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%     

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...CDG
NEAR TERM...RWH
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...RWH





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Page last modified: January 20, 2010

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