074
FXUS62 KGSP 220552
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
152 AM EDT TUE SEP 22 2026
WHAT HAS CHANGED
SLIGHT INCREASE IN RAIN CHANCES WEDNESDAY AND THURSDAY.
KEY MESSAGES
1. ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE
AHEAD OF A COLD FRONT THIS AFTERNOON INTO EARLY EVENING. THE
PRIMARY CONCERNS FROM ANY STRONGER STORMS ARE DAMAGING WIND GUSTS
AND EXCESSIVE RAINFALL.
2. MUCH COOLER TEMPERATURES FILTER INTO THE REGION WEDNESDAY
AND FALL BELOW NORMAL INTO THURSDAY. A FEW POCKETS OF RAINFALL
POSSIBLE BEFORE DRIER CONDITIONS DEVELOP BY FRIDAY.
DISCUSSION
KEY MESSAGE 1: ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS ARE
POSSIBLE AHEAD OF A COLD FRONT THIS AFTERNOON INTO EARLY EVENING.
THE PRIMARY CONCERNS FROM ANY STRONGER STORMS ARE DAMAGING WIND
GUSTS AND EXCESSIVE RAINFALL.
WITH THE FIRST DAY OF FALL UPON US, MOTHER NATURE ON QUEUE SHIFTS A
FRONTAL BOUNDARY TOWARD THE AREA. AHEAD OF THE COLD FRONT, ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND INTO THE
EVENING HOURS. THE BROAD OPEN WARM SECTOR PROVIDES SOME MOISTURE AND
DAYTIME HEATING, INSTABILITY AS FUEL FOR THESE STORMS. AS THE FRONT
ADVANCES, THIS SHOULD PROVIDE ENOUGH OF A TRIGGER TO POP OFF STORMS
THROUGHOUT THE ENTIRE AREA. A FEW OF THESE STORMS COULD BECOME
SEVERE WITH THE MAIN HAZARD BEING DAMAGING WINDS AND LOCALLY HEAVY
RAINFALL. FOR THIS, THE STORM PREDICTION CENTER HAS CONTINUED WITH A
MARGINAL (RISK 1 OF 5) FOR THE ENTIRE CWA. GUIDANCE SHOWS TIMING
STARTING OVER THE MOUNTAINS AS EARLY AS 1 PM AND QUICKLY MOVING
EASTWARD THROUGH THE 10 PM TO MIDNIGHT TIMEFRAME. IF THE FRONT
ADVANCES QUICKER, IT CUTS OFF THE FUEL FOR STORMS, HENCE ENDING
THUNDERSTORM CHANCES. EITHER WAY, ONE MORE DAY OF PESKY SHOWERS AND
THUNDERSTORMS BEFORE RELIEF FROM MONTHS OF DAILY STORMS AND HEAT
ARRIVES.
KEY MESSAGE 2: MUCH COOLER TEMPERATURES FILTER INTO THE REGION
WEDNESDAY AND FALL BELOW NORMAL INTO THURSDAY. A FEW POCKETS OF
RAINFALL POSSIBLE BEFORE DRIER CONDITIONS DEVELOP BY FRIDAY.
THE AREA BECOMES STUCK IN BETWEEN A RELATIVELY STRONG REX BLOCK,
WITH A RIDGE TO THE WEST AND UPPER TROUGH TO THE NORTH/NORTHEAST.
THIS STARTS TO BREAKDOWN BY THE WEEKEND AS AN AMPLIFYING UPPER LOW
PARKS OVER THE NORTHEAST AND REINFORCES COOLER AND DRIER AIR INTO
THE CWA THROUGH THE END OF DAY 7. WEDNESDAY AND THURSDAY LOOK TO BE
THE MORE SOMEWHAT WETTER DAYS, AS COLD AIR DAMMING DEVELOPS TUESDAY
NIGHT AND REMAINS IN PLACE THROUGH AT LEAST SATURDAY. REMAINING
MOISTURE AND NORTHEAST SURFACE WINDS, HELP TO REINFORCE CLOUD COVER
AND POCKETS OF RAINFALL IN SHOWERS. WITH THE CAD IN PLACE,
CONFIDENCE IS HIGHER THAT CONVECTION SHOULD NOT BE AN ISSUE AND ANY
RAINFALL WOULD JUST BE FROM LINGERING MOISTURE BEING FORCED UPWARDS
ON THE TERRAIN. BY FRIDAY, THE AREA OF LOW PRESSURE LIFTS FURTHER
OFF THE NORTHEAST COASTLINE, FILTERING IN EVEN DRIER AIR WITH A
BACKDOOR COLD FRONT, SNUFFING OUT RAIN CHANCES THROUGH THE
FORESEEABLE FUTURE. TEMPS LOOK TO BE WELL BELOW NORMAL FOR WED/THURS
WITH HIGHS IN THE 60S FOR THE MAJORITY OF THE AREA, BEFORE TICKING
UPWARD INTO THE NORMAL RANGE FOR THE REMAINDER OF THE FORECAST.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: A FEW SCATTERED -TSRA OVER KAVL SHOULD
DISSIPATE BY 07Z. FG LIKELY AT KHKY/KAVL 08Z-13Z. OTHERWISE, MVFR
CIGS WITH INTERMITTENT IFR THROUGH EARLY MORNING AT ALL SITES. A
COLD FRONT FROM THE WEST BRINGS ANOTHER ROUND OF TSRA TO ALL
TERMINALS BETWEEN 19-20Z AND LASTS THROUGH 00Z-02Z. THERE COULD BE
LINGERING SHRA AFTER AT MOST SITES. WINDS PREVAIL NE, BUT LIGHT AT
ALL SITES. IFR CIGS PREVAIL AT KCLT THROUGH 12Z TUESDAY.
OUTLOOK: RESTRICTIONS LIKELY THROUGH THURSDAY, WITH BREEZY WINDS.
DRIER CONDITIONS RETURN FRIDAY INTO THE WEEKEND, THOUGH
MOUNTAIN/RIVER VALLEY FOG/STRATUS COULD STILL DEVELOP NEAR DAYBREAK
EACH DAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
CP
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