877
FXUS62 KGSP 251025
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
625 AM EDT TUE AUG 25 2026
WHAT HAS CHANGED
THE AVIATION DISCUSSION UPDATED FOR THE 12Z TAF ISSUANCE.
KEY MESSAGES
1. ONE LAST DRY DAY TODAY. THEN HUMIDITY INCREASES ON WEDNESDAY
ALONG WITH DAILY SHOWER AND THUNDERSTORM CHANCES THAT CONTINUE
THROUGH THE REST OF THE WEEK.
DISCUSSION
KEY MESSAGE 1: ONE LAST DRY DAY TODAY. THEN HUMIDITY INCREASES ON
WEDNESDAY ALONG WITH DAILY SHOWER AND THUNDERSTORM CHANCES THAT
CONTINUE THROUGH THE REST OF THE WEEK.
DRY HIGH PRESSURE WILL LINGER OVER THE AREA TODAY, AS AN UPPER
TROUGH BEGINS TO FLATTEN OUT OVER THE EASTERN US. DEWPTS WILL ONCE
AGAIN MIX OUT INTO THE UPPER 50S TO LOWER 60S, AND FCST SOUNDINGS
CONTINUE TO REMAIN STABLE. HIGHS WILL SIMILAR TO YESTERDAY, RIGHT
AROUND NORMAL.
THE PATTERN STARTS TO CHANGE WEDNESDAY, AS A VIGOROUS UPPER
SHORTWAVE TROUGH DIVES INTO THE MIDWEST AND CARVES OUT A NEW
LONGWAVE TROUGH ACROSS THE OH/TN VALLEYS. FLOW WILL BACK TO S/SWLY
IN RESPONSE AND ADVECT MOISTURE BACK INTO THE FORECAST AREA. DEWPTS
ARE EXPECTED RISE INTO THE UPPER 60S TO AROUND 70 WEDNESDAY AFTN,
WHILE TEMPS REMAIN NEAR NORMAL. THE ATMOSPHERE SHOULD BECOME
MODERATELY UNSTABLE, AND MOUNTAIN-TOP CONVERGENCE SHOULD TRIGGER
DEEP CONVECTION. A WARM FRONT WILL ACTIVATE ACROSS THE I-20 CORRIDOR
AND START LIFTING NORTH INTO THE CWFA WEDNESDAY EVENING. SO POPS
RAMP UP INTO THE SOLID CHANCE RANGE ACROSS THE PIEDMONT, ROUGHLY
FROM SOUTH TO NORTH, AS THE FRONT HELPS TRIGGER MORE CONVECTION.
CONVECTION MAY LINGER INTO THE OVERNIGHT, BUT LATEST GUIDANCE SEEMS
TO BACKED OFF THE OVERNIGHT POPS A TAD. THURSDAY STILL LOOKS LIKE
THE MOST ACTIVE DAY, AS PWATS SURGE TO AROUND 2" WITH THE WARM
FRONT BASICALLY STALLING OUT ACROSS THE PIEDMONT. THERE MAY BE
A LOT OF CLOUDINESS TO START THE DAY, BUT ENOUGH SCATTERING OUT
SHOULD RESULT IN DECENT SBCAPE AND 20-30 KT OF 0-6KM BULK SHEAR TO
SUPPORT AT LEAST A MARGINAL SEVERE WEATHER THREAT THURSDAY AFTN
INTO THU EVENING. EXCESSIVE RAINFALL AND ISOLATED FLASH FLOODING
CANNOT BE RULED OUT AS WELL. POPS CONTINUE TO BE IN THE LIKELY
TO CATEGORICAL RANGE THURSDAY, AND HAVE INCREASED INTO A SIMILAR
RANGE ON FRIDAY, AS GUIDANCE HAS TRENDED WETTER.
A COLD FRONT SHOULD PUSH INTO THE AREA FROM THE NW ON FRIDAY, THEN
STALL OUT JUST TO OUR EAST SATURDAY. POPS GRADUALLY DECREASE OVER
THE WEEKEND, AS DRY AIR TRIES TO FILTER IN BEHIND THE FRONT. AN
UPPER RIDGE WILL BEGIN TO BUILD IN FROM THE SOUTHERN PLAINS SUNDAY
INTO MONDAY, FURTHER DRYING OUT THE CWFA AND ALLOWING TEMPS TO WARM
TO SLIGHTLY ABOVE NORMAL WITH SOME LINGERING HUMIDITY. THE HEAT
INDEX MAY PUSH INTO THE 90S ACROSS MUCH OF THE PIEDMONT SUNDAY
AND MONDAY, POSSIBLY REACHING 100 IN PARTS OF THE UPPER SAVANNAH
VALLEY AND SOUTHERN UPSTATE ON MONDAY.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: A FEW TO SCT HIGH-BASED CU FIELD IS EXPECTED
DURING THE AFTERNOON AND MAY LINGER INTO TONIGHT. SOME GUIDANCE
IS HINTING AT LOWER-LEVEL CLOUDS FORMING ACROSS THE MIDLANDS AND
POSSIBLY EXPANDING NORTH TOWARD THE TERMINALS. AS OF THE 12Z TAF
ISSUANCE, CONFIDENCE IS TOO LOW TO MENTION ANYTHING LOWER THAN
VFR-LEVEL. KCLT MAY SEE CIGS AROUND 5000 FT MID-TO-LATE WEDNESDAY
MORNING. WIND WILL BE LIGHT THRU THE PERIOD, MAINLY OUT OF THE
N/NE THRU AROUND MIDDAY, THEN BECOME MORE VRB IN THE AFTN AND THRU
TONIGHT. EXCEPT AT KAVL, WHERE IT SHOULD FAVOR A S DIRECTION. WIND
SHOULD TOGGLE TO SE OVER KCLT WEDNESDAY MORNING.
OUTLOOK: SHRA/TSRA COULD RETURN TO THE WESTERN TERMINALS WEDNESDAY
AFTERNOON. A BETTER CHANCE OF SHRA/TSRA IS FORECAST WEDNESDAY NIGHT
THROUGH SATURDAY. MOUNTAIN VALLEY FOG AND LOW STRATUS IS POSSIBLE
EACH MORNING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
ARK
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