789  
FXUS62 KGSP 170540  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
140 AM EDT WED SEP 17 2025  
   
SYNOPSIS  
 
DRIER CONDITIONS EXPECTED AS A COASTAL LOW LIFTS NORTHWARD OVER THE  
MID-ATLANTIC TODAY BEFORE PULLING AWAY FROM THE EAST COAST THURSDAY.  
WEAK HIGH PRESSURE BUILDS OVER THE SOUTHEAST THROUGH SATURDAY BEFORE  
STRONGER HIGH PRESSURE BUILDS OVER THE REGION LATE THIS WEEKEND INTO  
EARLY NEXT WEEK, ALLOWING MOSTLY DRY CONDITIONS TO CONTINUE. A  
WARMING TREND STARTS TODAY AND PEAKS ON FRIDAY BEFORE A COOLING  
TREND RETURNS BRIEFLY THIS WEEKEND.  
 
 
   
NEAR TERM /THROUGH TONIGHT/  
 
AS OF 130 AM WED: THE COASTAL SURFACE LOW, AND THE ASSOCIATED UPPER  
LOW, MOVE NORTHEAST AWAY FROM THE AREA TODAY. THERE WILL BE ANOTHER  
WEAK SHORT WAVE ROTATING AROUND THE LOW AND NEAR THE AREA AS IT IS  
DEPARTING. WHILE SOME MOISTURE LINGERS, THERE WILL BE LITTLE IN THE  
WAY OF INSTABILITY DEVELOPING. THE CAM GUIDANCE HINTS AS SOME  
ISOLATED SHOWERS DURING THE DAY, BUT THEY DON'T AGREE ON COVERAGE OR  
LOCATION. THE MODEL BLEND SHOWS A DRY FORECAST, SO HAVE FOLLOWED  
THAT TREND BUT DON'T BE SURPRISED IF AN AFTERNOON SHOWER OR TWO  
DEVELOPS. COPIOUS MORNING STRATOCU SHOULD SCATTER OUT BY AFTERNOON.  
HIGHS WILL BE AROUND NORMAL.  
 
DRY CONDITIONS CONTINUE TONIGHT WITH CLEARING SKIES. EXPECT ANOTHER  
ROUND OF MOUNTAIN VALLEY FOG OVERNIGHT. LOWS WILL BE AROUND NORMAL.  
 
 
   
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/  
 
AS OF 100 AM EDT WEDNESDAY...  
 
KEY MESSAGES:  
 
1) MOSTLY DRY WITH ABOVE NORMAL TEMPERATURES  
 
2) WARMING TREND CONTINUES WITH FRIDAY EXPECTED TO BE THE WARMEST  
DAY OF THE WEEK  
 
3) MOSTLY SUNNY EACH DAY AND MOSTLY CLEAR EACH NIGHT  
 
UPPER TROUGHING REMAINS IN PLACE OVER THE SOUTHEAST THROUGH DAYBREAK  
FRIDAY BEFORE BRIEF AND WEAK UPPER RIDGING DEVELOPS THE REST OF THE  
PERIOD. AT THE SFC, WEAK HIGH PRESSURE SITS OVER THE REGION THROUGH  
THE PERIOD KEEPING MOSTLY DRY AND MOSTLY SUNNY/MOSTLY CLEAR  
CONDITIONS AROUND. CANNOT ENTIRELY RULE OUT SOME ISOLATED CONVECTION  
EACH DAY BUT CONFIDENCE IS VERY LOW AS MOST OF THE HIGH-RES AND  
GLOBAL MODEL GUIDANCE SOURCES ARE DRY. THE WARMING TREND CONTINUES,  
PEAKING ON FRIDAY WITH HIGHS EAST OF THE MOUNTAINS CLIMBING INTO THE  
MID TO UPPER 80S. HIGHS THURSDAY WILL RUN ~5 DEGREES ABOVE NORMAL,  
RUNNING ~7-9 DEGREES ABOVE NORMAL FRIDAY. LOWS EACH NIGHT WILL RUN  
~2-5 DEGREES ABOVE NORMAL, WITH THE 50S EXPECTED ACROSS THE  
MOUNTAINS AND THE THE UPPER 50S TO MID 60S ELSEWHERE.  
 
 
   
LONG TERM /SATURDAY THROUGH TUESDAY/  
 
AS OF 130 AM EDT WEDNESDAY...  
 
KEY MESSAGES:  
 
1) TRENDING DRIER THROUGH THE PERIOD BUT WITH SLIGHTLY MORE CLOUDS  
 
2) BREEZY WINDS DEVELOP ON SUNDAY, MAINLY EAST OF THE MOUNTAINS  
 
3) ABOVE NORMAL TEMPERATURES CONTINUE DESPITE SLIGHTLY COOLER  
CONDITIONS RETURNING SUNDAY INTO TUESDAY  
 
WEAK UPPER RIDGING REMAINS IN PLACE THROUGH AT LEAST MONDAY BEFORE  
UPPER TROUGHING DEVELOPS TOWARDS THE END OF THE PERIOD. AT THE SFC,  
A STRONGER AREA OF HIGH PRESSURE NOSES DOWN THE EASTERN US THIS  
WEEKEND, LINGERING OVER THE REGION THROUGH MONDAY BEFORE GRADUALLY  
WEAKENING TUESDAY. MEANWHILE, A BACKDOOR COLD FRONT APPROACHES OUT  
OF THE NORTH SATURDAY BEFORE STALLING ACROSS THE FORECAST AREA  
SUNDAY INTO MONDAY. THE FRONT SHOULD PUSH SOUTH OF THE AREA LATE  
MONDAY INTO EARLY TUESDAY. THE LATEST NBM IS TRENDING DRIER THROUGH  
THE PERIOD BUT GLOBAL MODELS REMAIN INCONSISTENT RUN TO RUN,  
FLIPPING BACK AND FORTH BETWEEN WHETHER MOSTLY DRY CONDITIONS WILL  
CONTINUE OR WHETHER RAIN CHANCES WILL RETURN. THUS, WENT WITH NBM  
POPS FOR NOW AS CONFIDENCE ON CONVECTION RETURNING WITH THE SFC  
RIDGE IN PLACE REMAINS LOW. HOPEFULLY GUIDANCE WILL COME INTO BETTER  
AGREEMENT AS WE GET CLOSER TO THE WEEKEND. BREEZY WINDS WILL DEVELOP  
SUNDAY AFTERNOON, MAINLY EAST OF THE MOUNTAIN, IN ASSOCIATION WITH  
THE BACKDOOR COLD FRONT. THE FRONT WILL ALSO KEEP SOME PERIODIC  
CLOUD COVER AROUND. WARM CONDITIONS RETURN SATURDAY BUT HIGHS WILL  
NOT BE AS WARM AS FRIDAY. REGARDLESS, AFTERNOON TEMPS ON SATURDAY  
SHOULD RUN ~6-8 DEGREES ABOVE NORMAL. COOLER HIGHS RETURN SUNDAY  
INTO TUESDAY BUT AFTERNOON TEMPS SHOULD STILL END UP A FEW DEGREES  
ABOVE NORMAL SUNDAY AND MONDAY, WITH TUESDAY'S HIGHS ENDING UP ~5  
DEGREES ABOVE NORMAL. LOWS EACH NIGHT WILL REMAIN ~4-7 DEGREES ABOVE  
NORMAL.  
 
 
   
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/  
 
AT KCLT AND ELSEWHERE: A FEW SHOWERS OVER THE MOUNTAINS EARLY THIS  
MORNING MAY MOVE OVER KAVL. MOUNTAIN VALLEY FOG AND STRATUS HAVE  
ALREADY DEVELOPED AND WILL AFFECT KAVL AS WELL. HAVE IFR TEMPO LIFR  
THERE. ELSEWHERE MAINLY VFR STRATOCU EXPECTED WITH LIGHT WINDS. ANY  
RESTRICTIONS SHOULD BE GONE BY MID MORNING WITH VFR STRATOCU AND  
CIRRUS EXPECTED THROUGH THE DAY. ISOLATED SHOWERS ARE POSSIBLE BUT  
CHANCE TOO LOW FOR THE TAFS. LIGHT W TO NW WIND DEVELOPS, LIGHT NNW  
AT KAVL. SKIES CLEAR DURING THE EVENING WITH WINDS BECOMING CALM TO  
LIGHT AND VARIABLE. MOUNTAIN VALLEY FOG EXPECTED ONCE AGAIN.  
 
OUTLOOK: DRY CONDITIONS EXPECTED THROUGH SUNDAY. SOME MOUNTAIN  
VALLEY FOG WILL REMAIN POSSIBLE EACH MORNING WHEREVER CLOUDS DO NOT  
INHIBIT NOCTURNAL RADIATION.  
 
 
   
GSP WATCHES/WARNINGS/ADVISORIES  
 
GA...NONE.  
NC...NONE.  
SC...NONE.  
 
 
 
 
 
SYNOPSIS...AR  
NEAR TERM...RWH  
SHORT TERM...AR  
LONG TERM...AR  
AVIATION...RWH  
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