971
FXUS62 KGSP 302320
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
720 PM EDT WED SEP 30 2026
WHAT HAS CHANGED
NO MAJOR CHANGES TO THE FORECAST.
UPDATED THE AVIATION DISCUSSION FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
1. WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS STICK AROUND
FOR MOST LOCATIONS THROUGH FRIDAY, OUTSIDE OF THE POTENTIAL
FOR A FEW SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS FRIDAY
AFTERNOON/EVENING.
2. A COLD FRONT COMBINED WITH COLD AIR DAMMING WILL BRING COOLER
TEMPERATURES AND WIDESPREAD RAIN CHANCES OVER THE WEEKEND,
ESPECIALLY SATURDAY NIGHT INTO SUNDAY. LOCALLY HEAVY RAINFALL IS
POSSIBLE BUT CONFIDENCE IS LOW.
3. DRIER EARLY NEXT WEEK WITH A BRIEF WARM UP EXPECTED MONDAY
BEFORE BELOW NORMAL TEMPERATURES RETURN BY TUESDAY.
DISCUSSION
KEY MESSAGE 1: WELL ABOVE NORMAL TEMPERATURES AND DRY CONDITIONS STICK
AROUND FOR MOST LOCATIONS THROUGH FRIDAY, OUTSIDE OF THE POTENTIAL
FOR A FEW SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS FRIDAY
AFTERNOON/EVENING.
UPPER RIDGING REMAINS OVER THE SOUTHEAST THROUGH FRIDAY WHILE THE
WESTERN PERIPHERY OF SURFACE HIGH PRESSURE REMAINS EXTENDED OVER THE
REGION THROUGH THURSDAY. THIS PATTERN WILL KEEP DRY CONDITIONS
AROUND FOR MOST LOCATIONS THROUGH FRIDAY, WITH THE EXCEPTION OF THE
MOUNTAINS AS SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP
DURING PEAK HEATING FRIDAY AS THE WESTERN PERIPHERY OF THE SURFACE
HIGH NUDGES EASTWARD AHEAD OF AN APPROACHING COLD FRONT. A WARMING
TREND IS EXPECTED THROUGH FRIDAY AHEAD OF THE FRONT, WITH HIGHS
PEAKING IN THE UPPER 80S TO LOWER 90S FRIDAY AFTERNOON. WELL ABOVE
NORMAL TEMPERATURES ARE EXPECTED THROUGH FRIDAY NIGHT.
KEY MESSAGE 2: A COLD FRONT COMBINED WITH COLD AIR DAMMING WILL BRING
COOLER TEMPERATURES AND WIDESPREAD RAIN CHANCES OVER THE WEEKEND,
ESPECIALLY SATURDAY NIGHT INTO SUNDAY. LOCALLY HEAVY RAINFALL IS
POSSIBLE BUT CONFIDENCE IS LOW.
A COLD FRONT WILL TRACK ACROSS THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA THIS WEEKEND WITH HYBRID COLD AIR DAMMING DEVELOPING BEHIND
THE FRONT. THIS WILL ALLOW WIDESPREAD RAIN AND MUCH COOLER
TEMPERATURES TO DEVELOP. CANNOT ENTIRELY RULE OUT SOME EMBEDDED
THUNDER DURING PEAK HEATING EACH DAY BUT CONFIDENCE IS LOW. WENT
SLIGHTLY BELOW NBM FOR POPS ON SATURDAY AS RAIN CHANCES SHOULD PEAK
SATURDAY NIGHT INTO SUNDAY. RAINFALL TOTALS OVER THE WEEKEND HAVE
TRENDED DOWN SLIGHTLY COMPARED TO THE PREVIOUS FORECAST. ALTHOUGH
1.5" TO 2.0" PWATS ARE EXPECTED TO BE IN PLACE OVER THE WEEKEND,
CONFIDENCE ON THE HEAVY RAINFALL THREAT REMAINS LOW DUE TO DRY
ANTECEDENT CONDITIONS AS WELL AS MODELS BEING INCONSISTENT RUN TO
RUN REGARDING WHERE THE AXIS OF HEAVY RAINFALL WILL OCCUR. BLENDED
IN SOME OF THE NBM 10TH PERCENTILE FOR HIGHS ON SATURDAY TO ACCOUNT
FOR THE ONSET OF COLD AIR DAMMING. HIGHS ON SATURDAY MAY NEED TO BE
LOWERED FURTHER DEPENDING ON HOW FAR SOUTH THE WEDGE CAN DEVELOP SO
CONFIDENCE ON THE CURRENT FORECAST HIGHS FOR SATURDAY IS LOW. MUCH
COOLER AND BELOW NORMAL HIGHS ARE EXPECTED ON SUNDAY. LOWS SATURDAY
NIGHT AND SUNDAY NIGHT WILL REMAIN ABOVE NORMAL THANKS TO WIDESPREAD
RAIN AND THICK CLOUD COVER.
KEY MESSAGE 3: DRIER EARLY NEXT WEEK WITH A BRIEF WARM UP EXPECTED
MONDAY BEFORE BELOW NORMAL TEMPERATURES RETURN BY TUESDAY.
DRY HIGH PRESSURE BUILDS IN FROM THE NORTHWEST ON MONDAY AND LINGERS
THROUGH AT LEAST MID-WEEK. THE LATEST GFS KEEPS RAIN CHANCES AROUND
ON MONDAY WHILE THE EURO AND CANADIAN HAVE DRY CONDITIONS RETURNING
MONDAY. THE LATEST NBM APPEARS TO BE MORE IN LINE WITH THE GFS
SHOWING CHANCE POPS ACROSS NEARLY THE ENTIRE GSP FORECAST AREA ON
MONDAY. THUS, CONFIDENCE ON MONDAY POPS IS LOW. CONFIDENCE IS HIGHER
REGARDING DRY CONDITIONS TUESDAY INTO WEDNESDAY. HIGHS ON MONDAY
SHOULD REBOUND TO NEAR NORMAL BEFORE DROPPING BACK BELOW NORMAL
TUESDAY AND WEDNESDAY. LOWS SHOULD DROP INTO THE UPPER 40S ACROSS
THE NORTH CAROLINA MOUNTAINS MONDAY NIGHT AND TUESDAY NIGHT, WITH
LOCATIONS ABOVE 3500 FT POSSIBLY SEEING LOWS DROP INTO THE UPPER 30S
TUESDAY NIGHT.
AVIATION /00Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: MOSTLY VFR CONDITIONS WILL PREVAIL THROUGH
THE FORECAST PERIOD OUTSIDE OF MOUNTAIN VALLEY FOG/LOW STRATUS
EARLY THURSDAY MORNING. KEPT THE TEMPO MENTION FOR LIFR VSBYS AND
CIGS FROM 09Z THROUGH 13Z FOR KAVL. CONFIDENCE IS ON THE LOWER END
ON THE EXTENT OF MOUNTAIN VALLEY FOG/LOW STRATUS, ESPECIALLY WITH
MORE CIRRUS AROUND, BUT THAT SHOULDN'T FULLY ALTER MOUNTAIN VALLEY
FOG/LOW STRATUS DEVELOPMENT. LIGHT AND VARIABLE WINDS OVERNIGHT
WILL PICK UP OUT OF THE SOUTH TO SOUTHWEST BY THURSDAY AFTERNOON
AT ~3-6 KTS. CIRRUS AND DIURNAL CUMULUS WILL ROAM THE SKIES DURING
THE DAYTIME PERIOD.
OUTLOOK: DRY AND VFR THROUGH THURSDAY NIGHT OUTSIDE OF THE POTENTIAL
FOR MOUNTAIN VALLEY FOG/LOW STRATUS FRIDAY MORNING. MOISTURE WILL
BEGIN TO INCREASE ACROSS THE AREA FRIDAY AFTERNOON/EARLY EVENING,
MAINLY ACROSS THE MOUNTAINS. MORE WIDESPREAD SHOWERS AND ASSOCIATED
RESTRICTIONS DEVELOP AHEAD OF A COLD FRONT THIS WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
AR/CAC
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