799  
FXUS62 KGSP 142323  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
723 PM EDT SUN SEP 14 2025  
   
SYNOPSIS
 
 
DRY HIGH PRESSURE REMAINS OVER THE REGION THROUGH MONDAY. A  
DEVELOPING LOW PRESSURE SYSTEM ALONG THE CAROLINA COAST MAY BRING  
RAIN TO OUR AREA FOR THE MIDDLE OF THE WEEK. DRY HIGH PRESSURE  
RETURNS FOR THE LAST HALF OF THE WEEK.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
AS OF 100 PM SUNDAY, KEY MESSAGES:  
 
1. MOST LIKELY, ALL AREAS WILL REMAIN DRY THROUGH TONIGHT, WITH  
TEMPERATURES SLIGHTLY ABOVE NORMAL.  
 
2. INCREASING CLOUD COVER OVERNIGHT INTO MORNING, WITH ISOLATED  
SHOWERS OVER THE MOUNTAINS MONDAY AFTERNOON.  
 
3. SLIGHTLY COOLER IN MOST AREAS NORTHEAST OF I-26 MONDAY OWING  
TO CLOUD COVER.  
 
AN UPPER LOW NOW NEAR JACKSONVILLE IS IN THE PROCESS OF  
SHEARING OFF OF THE UPPER TROUGH DRIFTING OFF THE EAST COAST.  
THE SFC LOW WILL DRIFT NORTH, PROMOTING LOW TO MIDLEVEL MOISTURE  
ADVECTION ACROSS MUCH OF NC BY LATE MONDAY MORNING. THE UPPER  
LOW WILL DRIFT SLIGHTLY NORTHWARD, AND A VORT LOBE IS PROGGED TO  
ROUND IT AND LEAD TO DPVA SHIFTING EAST TO WEST ACROSS THE  
CAROLINAS LATE TONIGHT THRU MONDAY. TOGETHER, THESE DEVELOPMENTS  
SHOULD BRING INCREASED HIGH ALTITUDE CLOUD COVER BEGINNING IN  
THE PREDAWN HOURS, LIKELY JOINED BY LOWER CLOUD DECKS AFTER  
DAYBREAK. THE SUBSIDENCE INVERSION WEAKENS SUCH THAT DIURNAL  
MOUNTAIN CONVECTION APPEARS POSSIBLE MONDAY, WITH ENSUING  
EASTERLY UPSLOPE FLOW AND THE DPVA ENHANCING LIFT. A SLIGHT-  
CHANCE OR ISOLATED PRECIP MENTION RETURNS ALONG THE BLUE RIDGE  
ESCARPMENT, WITH MEAN FLOW VECTORS SUGGESTING ANY PROPAGATION  
WOULD BE TOWARD THE WEST OR SOUTHWEST FROM THERE.  
 
INCREASING CLOUDS TONIGHT REDUCE CONFIDENCE IN MOUNTAIN VALLEY FOG  
POTENTIAL, ALTHOUGH OVERALL SOME AREAS OF FOG ARE STILL LIKELY;  
THINKING IS FOG MAY JUST NOT BE AS LONG-LIVED AS IT WAS THE  
LAST COUPLE OF MORNINGS. CLOUD COVER AND/OR WEAK CAA ON NE FLOW  
IS EXPECTED TO BRING MAX TEMPS BACK A LITTLE BELOW NORMAL OVER  
THE NC PIEDMONT AND ADJACENT AREAS, BUT IN THE SUNNIER WESTERN  
MOUNTAINS AND SOUTHERN GA/SC ZONES, TEMPS SHOULD BE ABOUT THE SAME  
AS SUNDAY'S.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
 
 
AS OF 1:25 PM EDT SUNDAY: THE SHORT-TERM FCST PICKS UP AT 00Z ON  
TUESDAY WITH A REX BLOCK IN PLACE OVER MOST OF THE EASTERN CONUS.  
THIS BLOCKING PATTERN IS EXPECTED TO LINGER OVER OUR REGION THRU  
THE SHORT-TERM PERIOD, ALTHOUGH IT DOES GRADUALLY BREAK DOWN/ISSI-  
PATE AS THE PERIOD WEARS ON. AT THE SURFACE, BROAD CANADIAN HIGH  
PRESSURE WILL BE CENTERED NORTH OF NEW ENGLAND AS THE PERIOD BEGINS  
LATE MONDAY. AT THE SAME TIME, ANOTHER WEAK SFC LOW WILL HAVE DEDE-  
LOPED JUST OFF THE CAROLINA COAST AND BE SPREADING SOME AMOUNT OF  
ATLANTIC MOISTURE OVER THE CAROLINAS. OVER THE NEXT COUPLE OF DAYS  
MOST OF THE LATEST MODEL GUIDANCE HAS THE LOW GRADUALLY MOVING OVER  
THE NC COAST AND REMAINING THERE THRU THE END OF THE PERIOD LATE WED.  
OVERALL, NO MAJOR CHANGES WERE MADE TO THE FCST WITH A SLIGHT CHANCE  
FOR PRECIP ACROSS MOST OF OUR FCST AREA ON TUESDAY AND A SOLID CHANCE  
OVER PORTIONS OF THE NC MTNS AND INTO THE FOOTHILLS AND PIEDMONT. ON  
WEDNESDAY, PRECIP CHANCES HAVE TRENDED LOWER WITH ONLY A SLIGHT CHANCE  
NOW FCST FOR PORTIONS OF THE NC MTNS. NO EXCESSIVE QPF IS ANTICIPATED.  
HIGH TEMPERATURES HAVE TRENDED A BIT COOLER ON TUESDAY, ESPECIALLY  
OVER OUR NE ZONES WHERE MORE CLOUD COVER AND STRONGER NLY FLOW IS  
EXPECTED. TEMPS ARE WARMER ON WEDNESDAY BUT STILL EXPECTED TO BE A  
FEW DEGREES BELOW NORMAL FOR MID-SEPTEMBER.  
 

 
   
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
 
 
AS OF 1:15 PM EDT SUNDAY: THE EXTENDED FORECAST PICKS UP AT 00Z ON  
THURSDAY WITH WHAT'S LEFT OF A REX-TYPE BLOCKING PATTERN LINGERING  
OVER THE EASTERN CONUS. BY LATE THURSDAY, MOST OF THE LATEST GUIDANCE  
HAS THE REX BLOCK DISSIPATED. ON FRIDAY, BROAD UPPER TROFING WILL  
AMPLIFY OVER SOUTHERN QUEBEC AS ANOTHER CLOSED UPPER LOW DEVELOPS  
WEST OF THE GREAT LAKES. OVER THE WEEKEND, THIS UPPER LOW IS EXPEC-  
TED TO DRIFT EASTWARD, YET IT WILL LIKELY REMAIN WELL TO OUR NORTH  
AS FLAT UPPER RIDGING PERSISTS OVER THE SOUTHEAST AND MID-ATLANTIC.  
AT THE SFC, WEAK LOW PRESSURE WILL BE CENTERED SOMEWHERE OVER THE  
MID-ATLANTIC COAST AS THE PERIOD BEGINS LATE WEDNESDAY. ON THURSDAY,  
THIS SYSTEM WILL LIFT FURTHER NE AND DISSIPATE. OVER THE NEXT COUPLE  
OF DAYS, ANOTHER SFC LOW IS EXPECTED TO DEVELOP SOMEWHERE OVER THE  
NORTHERN PLAINS AND EVENTUALLY MOVE A WEAK COLD FRONT TOWARDS OUR  
AREA. IT REMAINS UNCLEAR WHEN THIS FRONT WILL ACTUALLY REACH OUR  
FCST AREA AND HOW MUCH IMPACT IT WILL HAVE ON OUR SENSIBLE WX. THIS  
IS PARTLY BECAUSE MOST OF THE LONG-RANGE GUIDANCE HAS ANOTHER ROBUST  
CANADIAN HIGH MIGRATING SE OVER THE WEEKEND. IT'S NOT CLEAR HOW FAR  
SOUTH THIS HIGH WILL SPREAD AND HOW MUCH IT WILL IMPACT THE APPROACH  
OF THE ABOVE-MENTIONED COLD FRONT. REGARDLESS, THE FIRST HALF OF THE  
PERIOD HAS TRENDED DRIER WITH DIURNALLY-DRIVEN SLIGHT CHANCE POPS OVER  
THE NC MTNS ON THURSDAY AND FRIDAY AND SOLID CHANCES FOR PRECIP ACROSS  
MOST OF OUR FCST AREA OVER THE WEEKEND. TEMPERATURES START OUT A FEW  
DEGREES ABOVE NORMAL ON THURSDAY AND REMAIN ABOVE NORMAL THRU SATURDAY.  
 

 
   
AVIATION /00Z MONDAY THROUGH FRIDAY/
 
 
AT KCLT AND ELSEWHERE: VFR CONDITIONS EXPECTED TO PREVAIL FOR THE  
MOST PART AT ALL SITES. TONIGHT, WINDS BECOME VRB AND CALM ACROSS  
THE MAJORITY OF TERMINALS. KAVL IS THE ONLY SITE THAT COULD HAVE A  
BRIEF IFR RESTRICTION FOR VSBY AS MORNING BR DEVELOPS. WITH THE  
INCREASED CLOUD COVER THROUGHOUT THE NIGHT, CONFIDENCE IS RATHER LOW  
BUT GIVEN THE PAST FEW NIGHTS, NOT OUT OF THE QUESTION. WILL KEEP A  
TEMPO FROM 11Z-13Z FOR 2SM VSBY. WINDS AFTER SUNRISE ARE SLOW AND  
SHOULD REMAIN LIGHT THROUGHOUT THE TAF PERIOD. A MOSTLY NE  
DIRECTIONS IS ANTICIPATED FOR THE PREVAILING WIND DIRECTION WITH A  
FEW LOW-END GUST POSSIBLE MONDAY AFTERNOON AT KCLT. AN ISOLATED  
SHOWER IS POSSIBLE ACROSS THE MOUNTAIN TERMINALS DURING THE  
AFTERNOON, BUT CONFIDENCE IS TOO LOW FOR A MENTION IN THE TAFS.  
 
OUTLOOK: MOSTLY VFR OUTSIDE OF MORNING MOUNTAIN VALLEY FOG AND LOW  
STRATUS THROUGH AT LEAST TUESDAY. RAIN CHANCES INCREASE ACROSS THE  
TERMINALS MONDAY NIGHT, POSSIBLY LINGERING INTO MID TO LATE WEEK.  
 

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

 
 

 
 
SYNOPSIS...DEO  
NEAR TERM...WIMBERLEY  
SHORT TERM...JPT  
LONG TERM...JPT  
AVIATION...CP  
 
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