138
FXUS62 KGSP 121038
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
638 AM EDT SAT SEP 12 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 12Z TAFS.
KEY MESSAGES
1. NOT AS HOT TODAY WITH MORE SHOWERS AND THUNDERSTORMS. HEAT
RETURNS SUNDAY WITH ISOLATED MOUNTAIN CONVECTION.
2. A BACKDOOR COLD FRONT PUSHES THROUGH THE AREA LATE MONDAY
KEEPING DRY BUT STILL WARM WEATHER OVER THE AREA THROUGH MUCH OF
NEXT WEEK, EXCLUDING DAILY MOUNTAIN SHOWERS/STORMS.
DISCUSSION
KEY MESSAGE 1: NOT AS HOT TODAY WITH MORE SHOWERS AND THUNDERSTORMS.
HEAT RETURNS SUNDAY WITH ISOLATED MOUNTAIN CONVECTION.
A SHORTWAVE MOVES OVER THE AREA LATE TODAY WHILE A LOW PRESSURE WAVE
DEVELOPS ALONG THE STALLED FRONTAL BOUNDARY OVER THE THE AREA. DEEP
MOISTURE INCREASES AHEAD OF THESE FEATURES. THE ATMOSPHERE WILL BE
WEAKLY UNSTABLE AS WELL. THE COMBINATION OF THESE FEATURES WILL
CREATE NUMEROUS SHOWERS AND THUNDERSTORMS. GIVEN THE WEAK
INSTABILITY, THE SEVERE STORM THREAT WILL BE LOW BUT NOT ZERO.
ISOLATED HEAVY RAINFALL WILL BE POSSIBLE GIVEN THE INCREASE IN PW
VALUES AND STORM COVERAGE. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL.
DRYING TAKES PLACE IN THE WAKE OF THE SHORTWAVE. HIGHS RISE BACK TO
ABOVE NORMAL WITH HIGHS AROUND 90 ACROSS MUCH OF THE AREA OUTSIDE OF
THE MOUNTAINS. THERE WILL BE ENOUGH LINGERING MOISTURE AND
INSTABILITY FOR ISOLATED DIURNAL CONVECTION ACROSS THE MOUNTAINS.
KEY MESSAGE 2: A BACKDOOR COLD FRONT PUSHES THROUGH THE AREA LATE
MONDAY KEEPING DRY BUT STILL WARM WEATHER OVER THE AREA THROUGH MUCH
OF NEXT WEEK, EXCLUDING DAILY MOUNTAIN SHOWERS/STORMS.
AN UPPER TROUGH SWINGS ACROSS THE GREAT LAKES AND INTO NEW ENGLAND
MONDAY. A BACK DOOR COLD FRONT CROSSES THE AREA LATE MONDAY. THE
FRONT LOOKS TO BE DRY. HIGHS ACTUALLY RISE A FEW DEGREES AHEAD OF
THE FRONT MONDAY THEN DROP TO NEAR OR SLIGHTLY ABOVE NORMAL BEHIND
THE FRONT TUESDAY. A STOUT UPPER RIDGE BUILDS INTO THE AREA FROM THE
WEST THROUGH WEDNESDAY THEN RETROGRADES SOMEWHAT THROUGH THE END OF
THE WEEK. THIS BRINGS TEMPS BACK ABOVE NORMAL INTO THE UPPER 80S TO
LOWER 90S FOR MOST LOCATIONS OUTSIDE OF THE MOUNTAINS. MOISTURE
LINGERS OVER THE MOUNTAINS WHERE DIURNAL CONVECTION CONTINUES.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: VFR MID AND HIGH CLOUDS WILL STICK AROUND
THROUGH THIS MORNING. GUIDANCE HAS CONTINUED TO SUPPORT LOWER
STRATUS DEVELOPING AT ALL TAF SITES BY DAYBREAK. DECIDED TO GO
PREVAILING SCT IFR AND BKN MVFR WITH A TEMPO FOR BKN IFR CIGS AT ALL
TAF SITES. CAN'T RULE OUT A FEW INSTANCES OF FOG, ESPECIALLY IN THE
MOUNTAIN VALLEYS AND LOCATIONS THAT RECEIVED HEAVY RAINFALL FROM
EARLIER AROUND DAYBREAK. THE LOW STRATUS MAY STICK AROUND THROUGH
THE MORNING HOURS BEFORE SLOWLY LIFTING AND SCATTERING BY THE
AFTERNOON. AN EARLIER ONSET TIME FOR SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE TERMINALS SO KEPT EITHER A TEMPO OR PROB30
MENTION FOR TSRA AND ASSOCIATED RESTRICTIONS. WITH THE SCATTERED
COVERAGE OF SHOWERS AND THUNDERSTORMS, WENT WITH PREVAILING VCSH
RATHER THAN SHRA. GUIDANCE HINTS AT ANOTHER ROUND OF LOW STRATUS
RESTRICTIONS OVERNIGHT TONIGHT AND HINTED AT THIS POTENTIAL IN THE
LAST LINE OF THE TAFS FOR ALL SITES. WINDS WILL BE LIGHT AND
VARIABLE OVERNIGHT AND PICK UP OUT OF THE SOUTH TO SOUTHWEST AT 5-10
KTS DURING THE DAYTIME PERIOD.
OUTLOOK: SCATTERED AFTERNOON AND EVENING STORMS WILL ONCE AGAIN BE
POSSIBLE SUNDAY. STORM CHANCES SHIFT TO THE MOUNTAINS MONDAY THROUGH
MUCH OF NEXT WEEK. MOUNTAIN VALLEY FOG/STRATUS WILL BE POSSIBLE
ANY GIVEN MORNING, ESPECIALLY IN PRONE/TRADITIONAL LOCATIONS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
CAC/RWH
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