856  
FXUS62 KGSP 151510  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
1110 AM EDT WED AUG 15 2018  
   
SYNOPSIS
 
 
AN UPPER-LEVEL RIDGE WILL CROSS FORECAST AREA TODAY AND HELP KEEP  
CONDITIONS MOSTLY DRY. MOISTURE LEVELS WILL BEGIN TO INCREASE  
THURSDAY AND CONTINUE THROUGH THE WEEKEND AS AN UPPER-LEVEL TROUGH  
IMPACTS THE REGION.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1040 AM: MID AND HIGH CLOUDS CONTINUE TO SPILL OVER THE  
SHALLOW RIDGE ATOP THE REGION, AND SKY COVER WILL BE BOOSTED  
SLIGHTLY FOR THE REST OF THE DAY. THE CLOUDS ARE PARTLY THIN AND  
SHOULD NOT HAVE MUCH IMPACT ON MAX TEMPERATURES THIS AFTERNOON, SO  
NO DOWNWARD ADJUSTMENTS WILL BE MADE FOR NOW. IN ADDITION TO THE  
EXPECTED ISOLATED TO SCATTERED SHOWER/THUNDERSTORM COVERAGE OVER THE  
MOUNTAINS THIS AFTERNOON IN WEAKER CAPPING, THE CONVECTION-ALLOWING  
MODELS HAVE BEEN RATHER PERSISTENT ABOUT A SECONDARY PATCH OF  
SHOWERS FORMING OVER THE PIEDMONT AROUND UNION COUNTY NC. THERE IS A  
SLIGHTLY BETTER POOL OF SBCAPE IN THAT REGION SO WILL JUST ADVERTISE  
ISOLATED SHOWERS THERE WITH THE UPDATE.  
 
THE CONVECTION SHOULD DISSIPATE QUICKLY WITH THE LOSS OF HEATING  
THIS EVENING. MOUNTAIN VALLEY FOG WILL BE POSSIBLE AGAIN OVERNIGHT,  
HOWEVER, COPIOUS CIRRUS MAY HELP KEEP COVERAGE LIMITED TO THE  
USUALLY MORE FAVORABLE LITTLE TN VALLEY. HIGHS WILL BE A COUPLE OF  
DEGREES ABOVE NORMAL WITH LOWS NEAR TO SLIGHTLY ABOVE NORMAL.  
 

 
   
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
 
 
AS OF 145 AM EDT WEDNESDAY: A RETURN TO A MOISTER AND UNSETTLED  
PATTERN WILL BEGIN THE SHORT RANGE PERIOD. UPPER LEVEL FLOW WILL  
BACK AS HEIGHTS LOWER THU AHEAD OF AN H5 TROF SWINGING THRU THE  
MIDWEST. CROSS SECTIONS SHOW THE SFC-H85 MEAN FLOW BECOMING ALIGNED  
MORE SW/LY DURING THE PERIOD WHICH WILL INCREASE BL MOISTURE AND IN  
TURN WILL LIMIT AFTERNOON SFC TD MIXING. THERE WILL BE AN UPTICK IN  
SBCAPE THU DUE TO THIS HIGHER LLVL MOISTURE...SO A FEW PULSE TSTMS  
COULD BECOME RATHER STRONG. HAVE KEPT THE BEST CHANCE POPS OVER THE  
HIGHER TERRAIN WHICH WILL BE ENHANCED BY MECH LIFT WHILE ISOL TSTM  
ACTIVITY IS ANTICIPATED ACROSS THE NON/MTNS.  
 
ON FRI...THE STRONGEST UPPER ENERGY WILL REMAIN WELL WEST OF THE  
FA...HOWEVER AN INCREASE IN CYCLONIC FLOW WITH EMBEDDED S/W ENERGY  
WILL IMPINGE UPON THE WRN ZONES. SO...WILL CONTINUE TO FAVOR THE  
HIGHER TERRAIN AS FAR AS SHRA/TSTM COVERAGE...BUT OVERALL ALL AREAS  
SHUD EXPERIENCE INCREASED ACTIVITY COMPARED TO THU AS A PRE-FRONTAL  
TROF DEVELOPS AND SLOWLY PROPAGATES EAST. THIS TROF COULD BECOME A  
FOCUSING ZONE FOR STG/SVR ACTIVITY DURING AFTERNOON WHILE 0-6 KM  
BULK SHEAR INCREASES YET REMAINS LOW-END. THERE WILL BE AN INCREASE  
IN STEERING FLOW AS WELL...SO EVEN WITH GOOD PRECIP RATES EXPECTED A  
HYDRO THREAT IS NOT ELEVATED ATTM. MAX AND MIN TEMPS WILL REMAIN  
ARND NORMAL LEVELS THRU THE PERIOD.  
 

 
   
LONG TERM /SATURDAY THROUGH TUESDAY/
 
 
AS OF 215 AM EDT WEDNESDAY: LITTLE CHANGE WAS MADE TO THE FCST GRIDS  
THRU THE EXT RANGE THANKS TO GOOD RUN-TO-RUN CONTINUITY BTW THE OP  
MODELS WRT THE OVERALL PATTERN AND RELATIVELY MINOR ENS SPREAD.  
STILL EXPECT AN UNSETTLED PERIOD WITH AFTERNOON AND NON/DIURNAL  
-SHRA/TSTMS EACH DAY AS A BROAD ULVL TROF PROVIDES GENERAL LIFT THRU  
SUN BEFORE A S/W H5 RIDGE CROSSES THE REGION MON INTO TUE. POPS HAVE  
BEEN MAINTAINED ABV CLIMO AND WILL FAVOR THE NC/GA/SC MTNS IN SW/LY  
TO W/LY LLVL FLOW AIDED BY AN INCREASE IN PWATS TO NEARLY 2.0  
INCHES. THE BEST ACCUM QPF RESPONSE CONTINUES WEST OF THE FA  
AREA...BUT WITH A STAGNANT LLVL BNDRY ALIGNED WITHIN THE UPPER FLOW  
OVER THE UPSTATE INTO NE GA...SOME ISSUES COULD BE HAD WITH HYDRO AS  
TRAINING AND BACK-BUILDING CELLS WILL BE POSSIBLE. THE SEVERE  
POTENTIAL LOOKS TO BE LOWER-END BUT NOT ZERO AS THE MID-LEVELS  
REMAIN RATHER WARM AND DEEP SBCIN WILL NEED TO BE OVERCOME THRU  
MOIST LOW LEVELS. TEMPS WILL REACH OR A REMAIN LITTLE BELOW NORMAL  
EACH DAY.  
 

 
   
AVIATION /15Z WEDNESDAY THROUGH SUNDAY/
 
 
AT KCLT AND ELSEWHERE: HIGH CLOUDS WILL BE THE MAIN SKY COVER FOR  
THE BULK OF THE PERIOD, WITH SCATTERED CUMULUS GRADUALLY DEVELOPING  
WITH HEATING THIS AFTERNOON. ANTICIPATE WINDS REMAINING QUITE LIGHT  
ACROSS THE TERMINAL FORECAST AREA, BUT BRIEFLY TURNING SOUTHWEST  
WILL LEE TROUGHING AT KCLT DURING THE MID TO LATE AFTERNOON, WITH  
MORE WNW TO NW ELSEWHERE. RIDGETOP CONVECTION SHOULD GENERALLY MISS  
KAVL THIS AFTERNOON/EVENING. CUMULUS WILL SLOWLY DISSIPATE THROUGH  
THE EVENING WITH CIRRUS REMAINING. MOUNTAIN VALLEY FOG, WITH PATCHY  
FOG ELSEWHERE, IS EXPECTED ONCE AGAIN BY MORNING. WINDS WILL REMAIN  
LIGHT AND VARIABLE INTO THURSDAY.  
 
OUTLOOK: INCREASING COVERAGE OF DIURNAL THUNDERSTORMS WILL DEVELOP  
FROM THURSDAY AFTERNOON THROUGH THE UPCOMING WEEKEND. RESTRICTIONS  
WILL BE LIMITED MAINLY TO AREAS IN HEAVY SHOWERS AND LOWER  
RESTRICTIONS ACROSS THE MOUNTAIN VALLEYS EACH MORNING.  
 
CONFIDENCE TABLE...  
 
15-21Z 21-03Z 03-09Z 09-12Z  
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAVL HIGH 100% 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 100% 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:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

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

 
 

 
SYNOPSIS...HG/SBK  
NEAR TERM...RWH  
SHORT TERM...SBK  
LONG TERM...SBK  
AVIATION...HG/RWH  
 
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