016  
FXUS62 KGSP 251042  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
642 AM EDT FRI JUL 25 2014  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL BUILD IN BEHIND A DEPARTING COLD FRONT ON FRIDAY  
LASTING THROUGH THE MAJORITY OF THE WEEKEND. ANOTHER COLD FRONT IS  
EXPECTED TO REACH THE AREA FROM THE NORTHWEST ON MONDAY MORNING AND  
INTO MONDAY AFTERNOON POTENTIALLY LEADING TO SCATTERED  
THUNDERSTORMS. HIGH PRESSURE WILL ONCE AGAIN REGAIN CONTROL ON  
TUESDAY LASTING THROUGH THE REMAINDER OF THE WORK WEEK WITH ONLY  
MINIMAL PRECIPITATION THREATS BY WEEKS END.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 640 AM...LOW CLOUDS SPREADING IN FROM THE EAST OR ALREADY IN  
PLACE ACROSS THE MTNS SHUD LIFT OR SCATTER OUT BY NOON. OTHERWISE...  
GOING FCST STILL LOOKS ON TRACK. UPDATES MAINLY FOR CURRENT  
CONDITIONS.  
 
AS OF 305 AM...SLOW MOVING COLD FRONT KEEPING ENUF LOW LEVEL  
CONVERGENCE ACROSS THE SRN UPSTATE TO BREAK THE CAP AND PRODUCE  
ISOLATED SHRA. THESE SHUD END OR MOVE SOUTH OF THE AREA BY DAYBREAK  
AS THE FRONT MOVES OUT OF THE AREA.  
 
ALTHOUGH THE FRONT MOVES SOUTH OF THE AREA...GUIDANCE IS NEARLY  
UNANIMOUS KEEPING LOW LEVEL MOISTURE ACROSS THE AREA. IN ADDITION...  
LOW LEVEL FLOW BECOMES SELY LEADING TO WEAK UPSLOPE FLOW. THIS IS  
FORECAST TO PROVIDE ENUF LIFT TO TAP THE ELEVATED INSTABILITY AND  
PRODUCE ISOLATED TO SCT CONVECTION ALONG THE BLUE RIDGE AND WEST  
ACROSS THE MTNS. GIVEN THE MDL SUPPORT...HAVE CHANGED THE FORECAST  
TO INCLUDE POP IN THIS AREA. THERE MAY ALSO BE SOME CONVECTION  
ACROSS THE FAR SRN CWFA AS THAT AREA WILL BE CLOSE TO THE FRONT.  
HOWEVER...BEST CHC WILL BE SOUTH OF THE CWFA. CLOUDS WILL LINGER  
THRU THE MORNING ACROSS MUCH OF THE NRN AND ERN CWFA...BEFORE MIXING  
OUT BY AFTERNOON. THIS AND THE COOLER AIR MASS BEHIND THE FRONT WILL  
LEAD TO HIGHS A LITTLE BELOW NORMAL.  
 
CONVECTION SHUD DISSIPATE DURING THE EVENING WITH LOSS OF HEATING.  
HOWEVER...CANNOT RULE OUT SOME LINGERING SHRA OVER THE BLUE RIDGE  
LATE INTO THE EVENING OR EARLY OVERNIGHT BEFORE THE LOW LEVEL FLOW  
BECOMES SWLY. LOWS SHUD BE NEAR NORMAL.  
 

 
   
SHORT TERM /SATURDAY 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. ELSEHWERE 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 THURSDAY/
 
 
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 PREFRONTAL 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 PRECIPIATION 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 /12Z FRIDAY THROUGH TUESDAY/
 
 
AT KCLT...IFR STRATUS HAS SPREAD ACROSS THE AIRFIELD AND WILL  
CONTINUE THRU MID-MORNING WHEN A SLOW RISE TO LOW VFR BY 18Z  
DEVELOPS. THAT SAID...MOISTURE IS SHALLOW AND CIGS COULD SCATTER OUT  
BEFORE LIFTING. FEW TO SCT LOW VFR CLOUDS EXPECTED THRU THE EVENING  
AND OVERNIGHT. NELY WIND BECOMES ENE THIS AFTERNOON AND EVENING THEN  
CALM OVERNIGHT. RIGHT NOW...DO NOT EXPECT ANY RESTRICTIONS  
OVERNIGHT.  
 
ELSEWHERE...LOW STRATUS IS MAKING A RUN FROM THE EAST AT THE NON MTN  
SITES. LOW VFR CIGS HAVE DEVELOPED AND MVFR OR EVEN THE IFR DECK  
COULD DEVELOP. IF SO...SHUD BE A RELATIVELY QUICK RETURN TO VFR...  
GENERALLY BEFORE NOON. THEN VFR EXPECTED THRU THE REST OF THE  
PERIOD. NELY WIND BECOMES ELY OR SELY BY LATE AFTERNOON WITH  
GENERALLY CALM WIND OVERNIGHT. KAVL WILL SEE MVFR OR IFR THIS  
MORNING WITH LOW VFR DEVELOPING BY NOON. NLY WIND BECOMES SLY FOR  
THE AFTERNOON...THEN CALM OVERNIGHT. ISOLATED CONVECTION WILL  
DEVELOP ACROSS THE MTNS...BUT CHC TOO LOW FOR TAF INCLUSION. KAVL  
COULD SEE RESTRICTIONS FROM FOG TOWARD DAYBREAK SAT.  
 
OUTLOOK...SAT THROUGH SUNDAY MORNING SHOULD BE QUIET AND VFR...  
EXCEPT FOR THE MTN VALLEYS WHERE EARLY MORNING FOG MAY OCCUR. SCT  
THUNDERSTORMS MAY RETURN TO THE FORECAST AREA FOR SUNDAY  
AFTERNOON...THOUGH MORE LIKELY MON...AS ANOTHER COLD FRONT  
APPROACHES AND THEN MOVES THROUGH THE AREA BY MON NIGHT.  
 
CONFIDENCE TABLE...  
 
10-16Z 16-22Z 22-04Z 04-10Z  
KCLT HIGH 83% HIGH 88% HIGH 100% HIGH 100%  
KGSP MED 66% HIGH 95% HIGH 100% HIGH 98%  
KAVL MED 67% HIGH 88% HIGH 93% HIGH 94%  
KHKY MED 66% HIGH 88% HIGH 99% HIGH 100%  
KGMU MED 74% HIGH 100% HIGH 100% HIGH 100%  
KAND MED 72% HIGH 93% 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...CDG  
NEAR TERM...RWH  
SHORT TERM...CDG  
LONG TERM...CDG  
AVIATION...RWH  
 
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