231
FXUS62 KGSP 270006
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
806 PM EDT TUE MAY 26 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 00Z TAFS.
KEY MESSAGES
1. NUMEROUS SHOWERS AND THUNDERSTORMS THIS EVENING INTO THE EARLY
OVERNIGHT HOURS WILL POSE A LOCALIZED THREAT OF FLASH FLOODING,
ESPECIALLY WHERE SOILS ARE SATURATED FROM RAINFALL OVER THE
HOLIDAY WEEKEND.
2. DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE THURSDAY
INTO THE WEEKEND AS A FRONT SETTLES THROUGH THE AREA. DRIER
CONDITIONS MAY BRIEFLY RETURN ON FRIDAY, BUT THERE IS NOT A SIGNAL
FOR MORE ROBUST DRYING UNTIL AT LEAST SUNDAY.
DISCUSSION
KEY MESSAGE 1: NUMEROUS SHOWERS AND THUNDERSTORMS THIS EVENING INTO
THE EARLY OVERNIGHT HOURS WILL POSE A LOCALIZED THREAT OF FLASH
FLOODING, ESPECIALLY WHERE SOILS ARE SATURATED FROM RAINFALL OVER
THE HOLIDAY WEEKEND.
OUR CWA REMAINS UNDER A DEEP SOUTHERLY FLOW REGIME BETWEEN THE
BERMUDA HIGH AND AN UPPER LOW OVER THE ARKLATEX REGION. MOISTURE IS
ROBUST, EXEMPLIFIED BY PWATS AT/ABOVE 1.8" ON MORNING RAOBS. THIS
MOISTURE PLUME FEEDS INTO AN ALMOST STATIONARY FRONT TO OUR NORTH,
OVER THE LOWER OH VALLEY AND MID-ATLANTIC. SHOWER AND THUNDERSTORM
ACTIVITY CONTINUE PRODUCING IMPRESSIVE RAINFALL RATES THIS EVENING.
SOUTHERLY, NEARLY UNIDIRECTIONAL SHEAR PROFILES ARE ROUGHLY PARALLEL
TO THE FLOW OVER THE REGION AND SO CONVECTION HAS GROWN UPSCALE INTO
NARROW BANDS, WITH TRAINING ALONG SAID BANDS. THUS, THE POTENTIAL
FOR ISOLATED FLASH FLOODING WILL CONTINUE THROUGH THE EARLY
OVERNIGHT HOURS.
BY TONIGHT THE UPPER LOW TO OUR WEST IS PROGGED TO LIFT NORTH AND
FILL. FLOW ALOFT VEERS TO A MORE WESTERLY DIRECTION IN RESPONSE, AND
LOW-LEVEL CONVERGENCE APPEARS TO BE WEAKER WEDNESDAY COMPARED TO
TUESDAY. PWATS ALSO DECLINE SLIGHTLY IN MODEL OUTPUT, REFLECTING THE
REDUCED MOISTURE FLUX; PROG SOUNDINGS APPEAR SLIGHTLY DRIER IN THE
MID TO UPPER LEVELS. IN GENERAL MODEL QPF RESPONSE IS LOWER AND CAMS
FAVOR MORE TYPICAL DIURNAL CONVECTIVE DEVELOPMENT OVER THE NC
MOUNTAINS WHICH MOVES EASTWARD INTO THE FOOTHILLS. CERTAINLY CANNOT
RULE OUT DEVELOPMENT ELSEWHERE, THOUGH LACKING A CLEAR LIFTING OR
FOCUSING MECHANISM, ISOLATED OR WIDELY SCATTERED POPS (20-30%)
APPEAR REASONABLE FOR THE AREAS NOT IN THE PATH OF THE TERRAIN-
INDUCED STORMS. MODEST 0-6KM SHEAR OF AROUND 30 KT IS SEEN ON PROG
SOUNDINGS IN OUR NORTHERN CWA WHERE COVERAGE LOOKS GREATEST, AND
WITH SLIGHTLY BETTER SFC-MIDLEVEL DELTA-THETA-E VALUES THAN TODAY.
IT IS FOR THIS REASON SPC EXTENDED A MARGINAL RISK INTO OUR NORTHERN
CWA, WHICH IS JUSTIFIABLE.
KEY MESSAGE 2: DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE
THURSDAY INTO THE WEEKEND AS A FRONT SETTLES THROUGH THE AREA. DRIER
CONDITIONS MAY BRIEFLY RETURN ON FRIDAY, BUT THERE IS NOT A SIGNAL
FOR MORE ROBUST DRYING UNTIL AT LEAST SUNDAY.
A SHORTWAVE DIGGING ACROSS THE MIDWEST LOOKS TO IMPINGE ON THE
STATIONARY FRONT WEDNESDAY NIGHT, PUSHING IT SOUTHWARD AS A COLD
FRONT. LOW-LEVEL FLOW TURNS MORE NORTHWESTERLY ALONG THE TN/NC
BORDER AND LIGHT PRECIP MAY CONTINUE THERE INTO EARLY THURSDAY. THE
FRONT ITSELF PUSHES EAST OF THE MOUNTAINS DURING THE DAY THURSDAY.
POST-FRONTAL DRYING MAY ACTUALLY INHIBIT CONVECTION IN THE NORTHERN
MOUNTAINS AND NORTHWEST NC PIEDMONT, BUT TO THE SOUTH OF THOSE
AREAS, APPEARS TO BE TIMED TO ENHANCE CI. SHEAR MAY BE SLIGHTLY
BETTER THAN WEDNESDAY, BUT LREF PROBABILITIES OF CAPE > 1000 ARE
LOWER, SO SEVERE THREAT IS NO HIGHER, POSSIBLY LOWER, COMPARED
TO WEDNESDAY. TEMPS SHOULD TREND A LITTLE WARMER THU AFTERNOON,
BACK INTO THE MID 80S FOR MOST OF THE PIEDMONT, OWING TO DOWNSLOPE
AND POSSIBLY COMPRESSIONAL WARMING.
GUIDANCE LARGELY CONTINUES TO DEPICT THE FRONT STALLING OVER THE
FAR SOUTHERN AND/OR SOUTHWESTERN PORTIONS OF THE CWA BY EARLY FRIDAY
MORNING, LEADING TO COOLER TEMPS AND MARGINALLY LOWER DEWPOINTS ON
FRIDAY. SOUTHERLY FLOW POTENTIALLY WILL BE REESTABLISHED ON FRIDAY
WITH A ANOTHER BAGGY UPPER TROUGH BEING PRESENT OVER THE SOUTHERN
PLAINS OR MID-SOUTH AND PRODUCING UPGLIDE OVER THE BOUNDARY,
SIMILAR TO THE PATTERN EARLIER IN THE WEEK. POPS PERSIST OVER THE
SW HALF OF THE AREA, INCREASING AND EXPANDING FRIDAY NIGHT INTO
SATURDAY WITH THAT TROUGH OPENING UP AND SHIFTING EAST OVER THE
AREA, ALONG WITH A REINFORCING WEDGELIKE SFC HIGH COMING IN FROM
THE NORTH. TEMPS REMAIN BELOW NORMAL THROUGH MONDAY, PARTICULARLY
THE DAILY MAX TEMPS. CONFIDENCE REMAINS LOW WHETHER THE WEDGELIKE
HIGH IS ABLE TO INDUCE APPRECIABLE DRYING; SMALL POPS PERSIST IN
MOST LOCATIONS UNTIL THE END OF THE PERIOD.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: SHOWERS AND THUNDERSTORMS CONTINUE STREAMING
ACROSS THE WESTERN CAROLINAS AS OF 00Z. WITH ACTIVITY EXPECTED TO
LINGER THROUGH AT LEAST THE EARLY OVERNIGHT HOURS, MAINTAINED TEMPOS
AND PROB30S FOR SHRA THROUGH 07Z-08Z FOR MOST TERMINALS, ALTHOUGH
HAVE ACTIVITY ENDING AROUND 04Z FOR KAND. DRIER CONDITIONS SHOULD
RETURN AFTER THIS TIME, OUTSIDE OF SOME SCATTERED SHRA/TSRA
WEDNESDAY AFTERNOON/EVENING. SHOULD SEE CIGS AND VSBYS TANK AGAIN
OVERNIGHT, RANGING MOST FROM IFR TO LIFR. CIGS AND VSBYS SHOULD
GRADUALLY LIFT TO VFR BY MID-MORNING WEDNESDAY. CONFIDENCE IS
HIGHEST AT KAVL, KAND, AND KHKY FOR DIURNAL THUNDERSTORM ACTIVITY ON
WEDNESDAY SO ONLY THESE TERMINALS HAVE PROB30S TOWARDS THE END OF
THE TAF PERIOD. WINDS WILL GENERALLY BE S/SW THROUGH THE PERIOD BUT
MAY GO LIGHT AND VRB AT TIMES THROUGH DAYBREAK WEDNESDAY. LOW-END
GUSTS MAY DEVELOP EAST OF THE MOUNTAINS WEDNESDAY AFTERNOON, WITH
CONFIDENCE HIGHEST AT KCLT.
OUTLOOK: THE PATTERN REMAINS UNSETTLED THROUGH THE REST OF THE WEEK
WITH AT LEAST SCATTERED DIURNAL CONVECTION EXPECTED EACH DAY. VSBY
AND CIG RESTRICTIONS WILL REMAIN POSSIBLE EACH NIGHT.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
AR/JCW
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