136  
FXUS62 KGSP 090612  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
212 AM EDT WED JUL 9 2025  
   
SYNOPSIS  
 
HOT AND HUMID CONDITIONS WILL COOL CLOSER TO NORMAL LATE THIS  
WEEK WITH NUMEROUS AFTERNOON AND EVENING SHOWERS AND THUNDER-  
STORMS EXPECTED EACH DAY. TEMPERATURES INCREASE AGAIN OVER THE  
WEEKEND AND EARLY NEXT WEEK AS AN UPPER RIDGE AMPLIFIES. DIURNAL  
SHOWERS AND THUNDERSTORMS WILL CONTINUE EACH DAY.  
 
 
   
NEAR TERM /THROUGH TONIGHT/  
 
AS OF 210 AM WEDNESDAY: MAINLY CIRRUS WITH SOME PATCHY STRATOCU  
EARLY THIS MORNING SHOULDN'T BE ENOUGH TO LIMIT ANOTHER ROUND OF  
MOUNTAIN VALLEY FOG. PATCHY FOG POSSIBLE ELSEWHERE. FOG SHOULD  
DISSIPATE RELATIVELY SHORTLY AFTER DAYBREAK.  
 
OVERALL A MUCH BETTER CHANCE OF CONVECTION TODAY WITH A MOIST,  
UNSTABLE AIR MASS OVER THE AREA. DEWPOINTS WILL MIX OUT SOMEWHAT  
THIS AFTERNOON, BUT NOT NEARLY TO THE EXTENT OF YESTERDAY. THIS WILL  
LEAD TO SBCAPE IN THE 2000 J/KG RANGE. WEAK HEIGHT FALLS ARE  
EXPECTED AS A SHORT WAVE APPROACHES THE AREA. SURFACE FORCING WILL  
BE IMPROVED BY AN OLD OUTFLOW BOUNDARY MOVING IN FROM THE WEST. WITH  
LESS MIXING, LFC'S WILL BE LOWER LEADING TO THICKER CAPE PROFILES  
THAN THE LAST FEW DAYS DESPITE MEAGER LAPSE RATES. BULK SHEAR  
ROMAINES 20 KTS OR LESS, WITH HIGHER VALUES NORTH OF OUR AREA. DCAPE  
AND SFC DELTA THET-E VALUES ARE ALSO LOWER THAN THE PAST FEW DAYS  
DUE TO DEEPER MOISTURE, BUT THEY WON'T BE ELIMINATED. CAMS ARE IN  
GENERAL AGREEMENT OF CONVECTION INITIATING OVER THE MOUNTAINS AND  
MOVING SOUTH AND EAST ACROSS THE AREA. A CONSOLIDATING COLD POOL  
COULD HELP STORMS BECOME SEMI-ORGANIZED AS THEY CROSS THE AREA. ALL  
OF THIS TO SAY SEVERE THUNDERSTORMS ARE POSSIBLE WITH DAMAGING WINDS  
IN WET MICROBURSTS THE MAIN THREAT. THAT SAID, THERE IS SOME LARGE  
HAIL POTENTIAL AS WELL GIVEN THE THICKER CAPE PROFILES. GUIDANCE IS  
ALSO CONSISTENT ON BETTER HEAVY RAIN POTENTIAL TO OUR EAST; HOWEVER,  
WITH THE HIGH PW VALUES AND SOMEWHAT ORGANIZED CONVECTION, THERE WILL  
BE AN ISOLATED FLASH FLOOD THREAT. SOME OF THE CAMS SHOW MERGING  
CONVECTION FROM THE MOUNTAINS AND CONVECTION MOVING NE ALONG THE SEA  
BREEZE WHICH MOVES WELL INLAND FROM THE COAST. THIS COULD SLOW  
CONVECTION DOWN AND POTENTIALLY LEAD TO SOME TRAINING CELLS. GIVEN  
THE UNCERTAINTY OF TIMING AND LOCATION OF THIS POTENTIAL, WILL HOLD  
OFF ON ANY WATCHES AT THIS TIME. HIGHS WILL BE FEW DEGREES ABOVE  
NORMAL TODAY, SO EVEN WITH LESS DEWPOINT MIXING, HEAT INDEX VALUES  
REMAIN BELOW 105.  
 
CONVECTION LINGERS INTO THE EVENING THEN DISSIPATES OR MOVES EAST OF  
THE AREA AROUND MIDNIGHT. MOUNTAIN VALLEY FOG IS EXPECTED ONCE  
AGAIN, AND AREAS OF LOW CLOUDS AND FOG WILL BE MORE LIKELY  
ELSEWHERE. LOWS WILL BE NEAR TO SLIGHTLY ABOVE NORMAL.  
 
 
   
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/  
 
AS OF 1:25 AM EDT WEDNESDAY: THE SHORT-TERM FCST PICKS UP AT 12Z ON  
THURSDAY WITH BROAD UPPER RIDGING TO OUR EAST AND WEST. THE LARGE-  
SCALE UPPER PATTERN WON'T CHANGE MUCH THRU THE PERIOD, WITH NUMEROUS  
WEAK UPPER IMPULSES TRANSLATING OVER OUR AREA ON THURSDAY AND FRIDAY.  
AT THE SFC, WE WILL REMAIN UNDER THE WESTERN PERIPHERY OF THE BERMUDA  
HIGH. THIS WILL KEEP MOIST, SWLY, LOW-LVL FLOW OVER OUR AREA THRU THE  
PERIOD. WE CAN EXPECT ACTIVE WEATHER EACH DAY WITH SCT TO NUMEROUS  
SHOWERS AND THUNDERSTORMS EACH AFTERNOON AND EVENING. THE PERSISTENT  
SWLY LOW-LEVEL FLOW AND FAVORABLE STORM-MOTION VECTORS SUGGEST A CON-  
TINUED RISK FOR ISOLATED AREAS OF EXCESSIVE RAINFALL AND LOCALIZED  
FLOODING EACH DAY. MODEL PROFILES CONTINUE TO SUPPORT SOME STRONG TO  
SEVERE STORMS EACH DAY AS WELL. HIGH TEMPERATURES ON THURSDAY SHOULD  
REMAIN NEAR-NORMAL WITH HIGHS TOPPING OUT A FEW DEGREES ABOVE-NORMAL  
ON FRIDAY. HEAT INDICES SHOULD REMAIN BELOW ADVISORY CRITERIA THRU THE  
PERIOD.  
 
 
   
LONG TERM /SATURDAY THROUGH TUESDAY/  
 
AS OF 1:15 AM EDT WEDNESDAY: THE EXTENDED PERIOD PICKS UP AT 12Z ON  
SATURDAY AND IS EXPECTED TO REMAIN ACTIVE THRU THE PERIOD. OUR AREA  
WILL REMAIN ON THE WESTERN PERIPHERY OF THE BROAD, SUBTROPICAL BERMUDA  
HIGH AND BROAD, WEAK HIGH PRESSURE TO OUR WEST AND NORTH. A COUPLE OF  
LOW PRESSURE SYSTEMS WILL LIFT UP AND OVER THE GREAT LAKES REGION THRU  
THE PERIOD, BUT ANY FRONTAL BOUNDARIES ASSOCIATED WITH THESE SYSTEMS  
ARE EXPECTED TO WASH OUT/DISSIPATE AS THEY APPROACH OUR AREA. OUR AREA  
WILL REMAIN UNDER MOIST, SWLY LOW-LEVEL FLOW THRU THE WEEKEND. EARLY  
NEXT WEEK, LOW-LEVEL WINDS COULD TAKE ON A WEAK NLY COMPONENT, BUT THEY  
WILL LIKELY BE LIGHT AND VRB FOR MUCH OF THE TIME. ALOFT, NUMEROUS WEAK  
SHORTWAVES WILL MOVE ACROSS THE OH AND TN VALLEYS AND OVER THE CENTRAL  
AND SOUTHERN APPALACHIANS OVER THE WEEKEND AND EARLY NEXT WEEK. THIS  
ENERGY ALOFT WILL HELP SUPPORT ABOVE-CLIMO POPS OVER THE MTNS AND NEAR-  
CLIMO POPS OUTSIDE THE MTNS EACH AFTERNOON/EVENING. TOWARDS THE END OF  
THE PERIOD, DIURNAL POPS INCREASE TO LIKELY ACROSS MOST OF OUR CWA. AT  
THIS TIME, THERE DOESN'T APPEAR TO BE A SIGNIFICANT SEVERE WX THREAT ANY  
PARTICULAR DAY, WITH ISOLATED STRONG TO SEVERE THUNDERSTORMS POSSIBLE  
EACH DAY. WITH THE PERSISTENT MOIST AIRMASS IN PLACE, THE BIGGER THREAT  
WILL LIKELY BE EXCESSIVE RAINFALL FROM THUNDERSTORMS THAT COULD PRODUCE  
LOCALIZED FLOODING. OTHERWISE, HIGH TEMPERATURES ARE EXPECTED TO REMAIN  
ABOUT A CATEGORY ABOVE NORMAL THRU MOST OF THE PERIOD. DEWPTS ARE FCST  
TO REMAIN LOW ENOUGH TO KEEP HEAT INDICES BELOW HEAT ADVISORY CRITERIA,  
ALTHOUGH SOME VALUES BETWEEN 100 AND 105 DEGREES ARE POSSIBLE OVER OUR  
SOUTHERN UPSTATE AND PIEDMONT ZONES EACH DAY.  
 
 
   
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/  
 
AT KCLT AND ELSEWHERE: MAINLY CIRRUS WITH SOME STRATOCU TO START  
EARLY THIS MORNING. EXPECT ANOTHER ROUND OF MOUNTAIN VALLEY FOG  
DISSIPATING AFTER DAYBREAK. PATCHY FOG POSSIBLE ELSEWHERE WITH KHKY  
HAVING THE BETTER CHANCE, BUT NOT HIGH ENOUGH FOR THE TAF AT THIS  
TIME. A BETTER CHANCE OF CONVECTION TODAY WITH A MOIST, UNSTABLE AIR  
MASS AND BOUNDARY INTERACTION. HAVE GONE WITH A MIX OF VCTS, TEMPO,  
AND PROB30 TO INDICATED THE BEST TIMES FOR CONVECTIVE COVERAGE. SOME  
OF THE CONVECTION COULD LINGER LATER INTO THE EVENING OR EARLY  
OVERNIGHT, BUT LEFT OUT FOR NOW DUE TO TAF RULES. LOW CLOUDS AND FOG  
MAY BE MORE LIKELY ACROSS THE AREA LATE TONIGHT. LIGHT S TO SW WIND  
THIS MORNING, PICKS UP SPEED DURING THE DAY, THEN TURNS NW BEHIND  
THE CONVECTION. THERE WILL BE SOME POTENTIAL FOR STRONG THUNDERSTORM  
OUTFLOWS, SO EXPECT VARIABLE FLIGHT CONDITIONS AND STRONG GUSTS NEAR  
STORMS.  
 
OUTLOOK: TYPICAL SUMMERTIME WEATHER IS EXPECTED INTO THE  
WEEKEND, WITH SCATTERED TO NUMEROUS THUNDERSTORMS MAINLY IN THE  
AFTERNOON/EVENING AND FOG AND/OR LOW STRATUS POSSIBLE EACH MORNING.  
 
 
   
GSP WATCHES/WARNINGS/ADVISORIES  
 
GA...NONE.  
NC...NONE.  
SC...NONE.  
 
 
 
 
 
SYNOPSIS...JPT  
NEAR TERM...RWH  
SHORT TERM...JPT  
LONG TERM...JPT  
AVIATION...RWH  
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