063
FXUS62 KGSP 261048
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
648 AM EDT WED AUG 26 2026
WHAT HAS CHANGED
POPS HAVE TRENDED DOWN SLIGHTLY FOR THURSDAY, BUT UP FOR FRIDAY
AND SATURDAY.
THE AVIATION DISCUSSION UPDATED FOR THE UPCOMING 12Z TAF
ISSUANCE.
KEY MESSAGES
1. DAILY SHOWER AND THUNDERSTORM CHANCES RETURN TODAY AND CONTINUE
THROUGH THE WEEKEND. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. A
DRYING AND WARMING TREND IS EXPECTED EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: DAILY SHOWER AND THUNDERSTORM CHANCES RETURN TODAY
AND CONTINUE THROUGH THE WEEKEND. LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE. A DRYING AND WARMING TREND IS EXPECTED EARLY NEXT WEEK.
SHORTWAVE ENERGY WILL DIVE INTO THE TN VALLEY TODAY, DEEPENING
A LONGWAVE TROUGH AS ITS AXIS APPROACHES FROM THE WEST. IN
RESPONSE TO HEIGHT FALLS ACROSS THE REGION, RETURN FLOW WILL
INCREASE AND ADVECT DEEP MOISTURE BACK INTO THE CWFA DURING THE
DAY TODAY. GUIDANCE IS IN PRETTY GOOD AGREEMENT ON A RETURN OF
DIURNAL CONVECTION ACROSS THE AREA, ESPECIALLY THE HIGH TERRAIN
WITH THE ADDED BENEFIT OF DIFFERENTIAL HEATING ACROSS THE MOUNTAIN
SLOPES. THE 00Z CAMS KEEP COVERAGE ISOLATED TO WIDELY SCATTERED,
WITH ACTIVITY PEAKING EAST OF THE MOUNTAINS THIS EVENING. PWATS
WILL CLIMB INTO THE 1.5-2.0" RANGE, AND COMBINED WITH DEEPENING
WARM-CLOUD LAYER AND SLOW STEERING FLOW, MAY RESULT IN A LOCALIZED
HEAVY RAIN THREAT. THE 00Z REFS AND HREF PMM QPF DON'T SHOW MUCH
OF A SIGNAL FOR HEAVY RAIN TO BE ANY MORE WIDESPREAD. GUIDANCE
STILL HINTING AT CONVECTION LINGERING WELL INTO THE EVENING AND
POSSIBLE INTO THE OVERNIGHT, AS SWLY LOW-LEVEL FLOW REMAINS ATOP A
LIFTING WARM FRONTAL ZONE AND APPROACHING UPPER WAVE ROUNDING THE
BASE OF THE LONGWAVE TROUGH. SEVERE THREAT LOOKS TO REMAIN LOW, BUT
PROBABLY NOT ZERO, AS SOUNDINGS BECOME MOIST AND SHEAR REMAINS WEAK.
LATEST GUIDANCE HAS TRENDED LOWER ON POPS THURSDAY, POSSIBLY DUE
TO A COMBINATION OF MORE PERSISTENT CLOUD COVER LIMITING INSOLATION
AND INSTABILITY, AND A MORE PRONOUNCE GAP BETWEEN UPPER SHORTWAVES
CROSSING THE AREA. STILL EXPECT AN ACTIVE DAY WITH HIGH-END CHC
TO LIKELY POPS. TEMPS WILL BE NEAR TO SLIGHTLY BELOW NORMAL WITH
INCREASED HUMIDITY. FRIDAY NOW LOOKS LIKE THE MOST CONVECTIVELY
ACTIVE DAY OF THE WEEK, WITH LIKELY TO CATEGORICAL POPS ACROSS THE
ENTIRE AREA. A COLD FRONT WILL APPROACH FROM THE WEST AND A FAIRLY
PRONOUNCED UPPER SHORTWAVE WILL CROSS THE AREA AS IT ROUNDS THE
BASE OF THE LONGWAVE TROUGH, PROVIDING ENHANCED FORCING. PWATS
WILL REMAIN HIGH BOTH THURSDAY AND FRIDAY. SO, THERE WILL BE A
MARGINAL THREAT OF EXCESSIVE RAINFALL, WITH A SLIGHT RISK IN THE
EXCESSIVE RAINFALL OUTLOOK IN THE UPPER SAVANNAH VALLEY. I WOULDN'T
BE SURPRISED IF A SLIGHT RISK GETS EXPANDED INTO THE AREA ON FRIDAY,
IF THE MODEL TRENDS HOLD.
A LARGE UPPER RIDGE WILL BEGIN TO EXPAND EASTWARD FROM THE SOUTHERN
PLAINS OVER THE WEEKEND, AND BECOME CENTERED OVER THE SOUTHEAST
EARLY NEXT WEEK. POPS WILL GRADUALLY DECREASE FROM SATURDAY THRU
THE WEEKEND, AS THE RIDGE BUILDS AND SFC HIGH PRESSURE PUSHES THE
WEAK FRONT SOUTHEAST OF THE AREA. TEMPS WILL REMAIN NEAR NORMAL
FOR HIGHS AND SLIGHTLY ABOVE NORMAL FOR LOWS IN THE MOIST AIR MASS
UNTIL MONDAY, WHEN TEMPS OVERALL BUMP UP ABOVE NORMAL WITH HEAT
INDICES PUSHING INTO THE UPPER 90S TO AROUND 100 MONDAY AND TUESDAY.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: PATCHY MVFR STRATUS HAS DEVELOPED ACROSS
KCLT AREA. CONFIDENCE REMAINS LOW ON HOW EXTENSIVE THE CLOUDS WILL
BECOME BEFORE SCATTERING OUT AFTER SUNRISE. HAVE A FEW015 IN THE
TAF, BUT AMENDMENTS MAY BE NEEDED IF THE CLOUDS REALLY FILL IN. THE
MVFR CLOUDS MAY ALSO AFFECT KHKY THIS MORNING, BUT SHOULD MAINLY
STAY FEW TO SCT. FOG IS ALSO CLOSE TO KAVL. LIGHT AND VARIABLE
WINDS SHOULD TOGGLE TO S/SE BY MIDDAY, AND REMAIN LIGHT. A MORE
SUBSTANTIAL CU FIELD IS EXPECTED TO FORM, WITH A RETURN OF AFTN
CONVECTION ACROSS THE MOUNTAINS, EXPANDING INTO THE PIEDMONT LATE
AFTN THRU THIS EVENING. COVERAGE LOOKS TO BE ISOLATED TO SCATTERED,
SO WILL CONTINUE WITH PROB30 GROUPS, INCLUDING KCLT. CONVECTION
COULD LINGER THRU LATE EVENING, BUT SHOULD DISSIPATE OVERALL
OVERNIGHT. DEPENDING ON HOW MUCH RAIN FALLS TODAY AND HOW MUCH
MID CLOUDS CAN CLEAR OUT, THERE MAY BE SOME IFR STRATUS AND FOG
DEVELOPMENT ACROSS THE AREA LATE TONIGHT. BUT SOME GUIDANCE KEEPS
LOW-VFR CLOUDS AROUND INSTEAD, MAKING FOR A LOW-CONFIDENCE FORECAST.
OUTLOOK: MORE NUMEROUS TO WIDESPREAD SHRA/TSRA IS FORECAST THURSDAY
AND FRIDAY, THEN DECREASES TO MORE ISOLATED TO SCATTERED SATURDAY
AND SUNDAY. 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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