348  
FXUS62 KGSP 142351  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
751 PM EDT FRI AUG 14 2020  
   
SYNOPSIS
 
 
NUMEROUS TO WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED  
THROUGH SATURDAY WITH HIGHS SLIGHTLY BELOW NORMAL. THUNDERSTORM  
CHANCES DIMINISH SUNDAY THEN SLOWLY INCREASE THROUGH THE WEEK. HIGHS  
WILL BE AROUND NORMAL THROUGH THE FIRST PART OF THE WEEK THEN FALL  
BELOW NORMAL.  
 

 
   
NEAR TERM /THROUGH SATURDAY/
 
 
AS OF 740 PM EDT FRIDAY: WATER VAPOR IMAGERY SHOWS THE BASE OF A  
DIGGING TROUGH STEADILY ADVANCING EASTWARD ACROSS WESTERN TENNESSEE  
THIS EVENING, WITH BETTER FORCED CONVECTIVE COVERAGE DEVELOPING  
UPSTREAM ACROSS ALABAMA AND GEORGIA. COVERAGE HAS BEEN SPARSER AND  
WEAKER ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THUS FAR,  
AND WHAT OUTFLOWS EXIST AT PRESENT DO NOT LOOK TERRIBLY ROBUST. POPS  
HAVE THUS BEEN SHAVED A BIT IN PIEDMONT SECTIONS, BUT WITH CONTINUED  
LIKELY COVERAGE ACROSS THE HIGHER TERRAIN AND THE NC FOOTHILLS FOR  
ONGOING SHOWERS AND EMBEDDED THUNDERSTORMS. IT'S QUITE POSSIBLE THAT  
THE REGION WILL STILL EXPERIENCE AN UPTICK TONIGHT AS THE UPSTREAM  
COVERAGE ARRIVES FROM THE SOUTHWEST LATER THIS EVENING, BUT SBCAPE  
VALUES WILL START TRENDING DOWN SOON AND THERE MAY NOT BE GOOD  
INSTABILITY TO GET COVERAGE BACK UP ABOVE THE HIGH SCATTERED RANGE.  
WILL KEEP THE BEST OVERNIGHT POPS IN SOUTHWEST MOUNTAIN SECTIONS,  
CLOSER TO THE DEEPER MOISTURE AND FORCING AND WHERE UPSLOPE FLOW  
WILL BE BEST. WILL LIKELY ALLOW THE FLASH FLOOD WATCH TO EXPIRE ON  
SCHEDULE AT MIDNIGHT, WITH JUST ABOUT ANY LOCATION POSSIBLY SEEING  
LOCALIZED FLOODING WITH ANY TRAINING SHOWERS OVERNIGHT.  
 
POPS WILL RAMP UP A BIT SOONER THAN TYPICAL DIURNAL TRENDS INDICATE  
ON SATURDAY, AS UPPER DPVA AND JET ENERGY BEGINS TO PUSH EAST INTO  
THE AREA. THE BEST 2+ INCH PRECIPITABLE WATER VALUES OF THE EVENT  
WILL OCCUR ON SATURDAY, AND THE DEEP FORCING, ABUNDANT MOISTURE AND  
SLIGHTLY IMPROVED LAPSE RATES SHOULD YIELD MORE COVERAGE, STRONGER  
STORMS, AND A SLIGHT UPTICK IN THE HYDRO THREAT WITH ANY TRAINING  
CELLS. A NEW FLASH FLOOD WATCH COULD BE NEEDED AT SOME POINT  
SATURDAY WHERE ANTECEDENT RAINFALL CONDITIONS ARE THE WETTEST  
(MAINLY WESTERN NC). EXPECT MILD AND MUGGY CONDITIONS OVERNIGHT, AND  
THEN BELOW CLIMO MAXES SATURDAY AFTERNOON GIVEN ALL THE CLOUD COVER.  
 

 
   
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/
 
 
AS OF 200 PM EDT FRIDAY: THE MID LEVEL TROF WILL BE PULLING EAST OF  
THE AREA BY SATURDAY NIGHT. WE SHOULD HAVE SOME SHOWERS AND STORMS  
IN THE EVENING, BUT THEY WILL MOVE EAST OF THE AREA LEAVING A DRY  
OVERNIGHT PERIOD. AS THE TROF MOVES EAST, A DRIER AIR MASS WILL  
MOVE INTO THE AREA FOR SUNDAY AND MONDAY AS NORTHWEST MID LEVEL FLOW  
DEVELOPS. THERE WILL BE A SMALL CHANCE OF A SHOWER OR STORM EACH DAY  
BUT CONDITIONS SHOULD BE QUIET OVERALL.  
 
HIGHS BOTH DAYS WILL BE NEAR CLIMO. SLIGHTLY LOWER DEWPOINTS WILL  
MAKE CONDITIONS RELATIVELY COMFORTABLE FOR MID AUGUST.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 200 PM EDT FRIDAY: ANOTHER MID LEVEL TROF IS EXPECTED TO  
DEVELOP TO OUR WEST FOR THE MIDDLE TO LATTER PART OF NEXT WEEK. THIS  
SHOULD ACT TO PULL DEEPER MOISTURE BACK INTO THE AREA LEADING TO A  
MORE ACTIVE, MAINLY DIURNAL, CONVECTIVE PATTERN. THE INCREASED CLOUD  
COVER AND RAINFALL SHOULD KEEP HIGH TEMPERATURES IN CHECK AND A FEW  
DEGREES BELOW CLIMO THROUGH THE PERIOD.  
 

 
   
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
 
 
AT KCLT AND ELSEWHERE: CONVECTION CHANCES WILL BE BEST THIS  
EVENING FROM KAVL TO KHKY, BUT WITH A SHARP GRADIENT TO LOWER  
CHANCES ACROSS THE UPSTATE TAF SITES AND KCLT, WHERE MAINLY VCSH OR  
VCTS IS WARRANTED THROUGH EARLY OVERNIGHT. ABUNDANT MOISTURE SHOULD  
YIELD ANOTHER ROUND OF LOW CLOUDS AND FOG, WITH IFR TO LIFR  
CONDITIONS MAINLY FROM KAVL TO KHKY, BUT WITH MVFR LIKELY AT THE  
OTHER SITES, INCLUDING KCLT, AND A WINDOW OF IFR POSSIBLE AS WELL.  
RESTRICTIONS WILL BE SLOW TO LIFT THROUGH NOON, AND INSOLATION WILL  
BE LIMITED BY ABUNDANT CLOUDS THROUGH THE AFTERNOON HOURS. EXPECT  
MAINLY AFTERNOON VFR CONDITIONS BUT WITH MVFR TO IFR POSSIBLE IN ANY  
HEAVY DOWNPOURS. THE BEST CONVECTIVE CHANCES WILL BE DURING THE  
AFTERNOON AND EVENING HOURS AS THE UPPER TROUGH MAKES A PUSH INTO  
THE REGION. EXPECT VERY SLOW DRYING TO BEGIN FROM THE WEST RIGHT  
AROUND THE END OF THE TAF PERIOD, BUT WITH LOW-LEVEL MOISTURE  
PERSISTING. LIGHT AND VARIABLE WINDS WILL BE MAINLY S TO SW WITH ANY  
MIXING TONIGHT THROUGH SATURDAY, EXCEPT NW AT TIMES IN THE FRENCH  
BROAD VALLEY TONIGHT. WINDS WILL BE BRIEFLY GUSTY NEAR ANY  
THUNDERSTORMS.  
 
OUTLOOK: SLIGHTLY LESS THUNDERSTORM COVERAGE IS EXPECTED SUNDAY AND  
MONDAY COMPARED TO RECENT DAYS, BUT PERHAPS STILL SLIGHTLY ABOVE  
NORMAL AS LOW-LEVEL MOISTURE CONTINUES. AN UPTICK IN THUNDERSTORM  
COVERAGE IS THEN LIKELY TUESDAY THROUGH WEDNESDAY. FOG AND LOW  
STRATUS RESTRICTIONS WILL BE POSSIBLE EACH MORNING, ESPECIALLY OVER  
THE USUAL MOUNTAIN VALLEYS.  
 
CONFIDENCE TABLE...  
 
00-06Z 06-12Z 12-18Z 18-00Z  
KCLT HIGH 97% MED 78% MED 69% HIGH 96%  
KGSP HIGH 98% MED 71% MED 73% HIGH 88%  
KAVL MED 74% LOW 58% MED 78% MED 75%  
KHKY HIGH 90% MED 62% MED 65% MED 78%  
KGMU HIGH 98% MED 70% MED 68% HIGH 90%  
KAND HIGH 98% MED 78% MED 79% HIGH 94%  
 
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING  
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY  
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES ARE AVAILABLE AT  
THE FOLLOWING LINK:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

 
   
GSP WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
NC...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NCZ033-  
035>037-056-057-501>506.  
SC...NONE.  
 

 
 

 
SYNOPSIS...DEO  
NEAR TERM...HG  
SHORT TERM...SCW  
LONG TERM...SCW  
AVIATION...HG  
 
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