200
FXUS62 KGSP 210701
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
301 AM EDT FRI AUG 21 2026
WHAT HAS CHANGED
CONFIDENCE IS INCREASING ON HEAVY RAIN POTENTIAL AND ISOLATED
FLASH FLOODING THIS AFTERNOON INTO THIS EVENING.
THE AVIATION FORECAST WAS UPDATED FOR THE 06Z TAF ISSUANCE.
KEY MESSAGES
1. MORE WIDESPREAD COVERAGE OF SHOWERS AND THUNDERSTORMS IS
EXPECTED ACROSS THE AREA THIS AFTERNOON THROUGH THIS EVENING. A
FEW STORMS MAY BE SEVERE, PRODUCING DAMAGING WIND GUSTS. THERE
WILL ALSO BE A THREAT OF LOCALLY HEAVY RAINFALL AND ISOLATED
FLASH FLOODING.
2. DRIER WEATHER RETURNS SUNDAY AND CONTINUES INTO EARLY NEXT
WEEK. A RETURN OF AFTERNOON SHOWER AND THUNDERSTORM CHANCES IS
EXPECTED BY MIDWEEK.
DISCUSSION
KEY MESSAGE 1: MORE WIDESPREAD COVERAGE OF SHOWERS AND THUNDERSTORMS
IS EXPECTED ACROSS THE AREA THIS AFTERNOON THROUGH THIS EVENING. A
FEW STORMS MAY BE SEVERE, PRODUCING DAMAGING WIND GUSTS. THERE
WILL ALSO BE A THREAT OF LOCALLY HEAVY RAINFALL AND ISOLATED
FLASH FLOODING.
A DIGGING UPPER TROUGH COMBINED WITH HIGH PWATS WILL RESULT
IN AN ACTIVE CONVECTIVE DAY ACROSS THE AREA. AN MCS CURRENTLY
CROSSING NORTHERN GA IS EXPECTED TO WEAKEN BEFORE REACHING THE
WESTERN EDGE OF THE CWFA. BUT SOME DEBRIS CLOUDINESS AND LINGERING
SHOWERS AND STORMS MAY WORK OVER A GOOD CHUNK OF THE AREA THIS
MORNING. DEPENDING ON HOW THE CLOUDS ERODE, DIFFERENTIAL HEATING
COULD SET OFF CONVECTION BY EARLY AFTN IN THE EASTERN ZONES. THEN
MORE SUBSTANTIAL CONVECTION IS EXPECTED TO FORM ACROSS THE AREA,
AS A COLD FRONT SAGS SOUTHEASTWARD INTO THE AREA. THE LATEST
MODELS, ALONG WITH THE CAMS AGREE ON LIKELY TO CATEGORICAL POPS
THIS AFTN INTO THIS EVENING. THERE IS SOME SIGNAL FOR LOCALLY
HEAVY RAINFALL, ESPECIALLY ACROSS THE SOUTHEAST THIRD OR SO OF THE
FORECAST AREA. PARTS OF THE CHARLOTTE AREA DID RECEIVE SOME DECENT
RAINFALL LAST NIGHT, SETTING UP ELEVATED SOIL MOISTURE. A FLOOD
WATCH WAS CONSIDERED, BUT CONFIDENCE ON WHERE THE HEAVY RAIN SETS
UP IS STILL TOO LOW. SOME GUIDANCE KEEPS IT MOSTLY JUST EAST OF
THE CWFA, WITH A SECONDARY MAXIMUM ALONG THE EASTERN BLUE RIDGE
ESCARPMENT. THE 00Z HREF HAS SOME 3"+ PMM QPF BULLSEYES AROUND
CHARLOTTE IN THE 21-00Z TIME FRAME. THE REFS IS SIMILAR, BUT A
LITTLE SOUTH AND EAST. SO THE CONDITIONS BEAR WATCHING AND FLOOD
WATCH MAY BE ISSUED LATER THIS MORNING FOR PARTS OF THE CWFA,
IF CONFIDENCE INCREASES.
THE OTHER CONCERN TODAY WILL BE A SEVERE THREAT. POCKETS OF 2000+
J/KG OF SBCAPE, ALONG WITH 25-30 KT OF 0-6 KM SHEAR COULD SUPPORT A
FEW SEVERE STORMS ORGANIZING ALONG OUTFLOWS AND PRODUCING DAMAGING
WIND GUSTS. VERY MOIST PROFILES SHOULD LIMIT DCAPE SOMEWHAT, AND
LIMIT COLD POOL FORMATION. NEVERTHELESS, THE NEW DAY 1 CONVECTIVE
OUTLOOK HAS CHARLOTTE AND VICINITY IN A SLIGHT RISK, AND MOST OF
THE REST OF THE CWFA IN A MARGINAL RISK FOR DAMAGING WIND GUSTS.
KEY MESSAGE 2: DRIER WEATHER RETURNS SUNDAY AND CONTINUES INTO EARLY
NEXT WEEK. A RETURN OF AFTERNOON SHOWER AND THUNDERSTORM CHANCES
IS EXPECTED BY MIDWEEK.
AN EASTERN CONUS UPPER TROUGH WILL CONTINUE TO DIG ON SATURDAY,
BUT THE AXIS WILL SHIFT SLIGHTLY EAST. THIS SHOULD ALLOW SOME DRIER
AIR TO FILTER IN FROM THE WEST, AS A SLOW-MOVING COLD FRONT WILL
STILL BE IN THE EASTERN PART OF THE CWFA. THERE WILL PROBABLY
BE ENOUGH LINGERING MOISTURE COMBINED WITH COOLER AIR ALOFT TO
ALLOW FOR SCATTERED DIURNAL CONVECTION TO DEVELOP AGAIN ACROSS THE
AREA. POPS WILL BE MAINLY IN THE LOW-END CHANCE RANGE, HIGHEST EAST.
THE UPPER TROUGH AXIS SHIFTS FURTHER EAST ON SUNDAY, AND USHERS IN
DRIER, MORE STABLE AIR COMPLETELY INTO THE REGION. DRY WEATHER WITH
SEASONABLY WARM CONDITIONS IS EXPECTED SUNDAY THROUGH TUESDAY. THEN,
THE TROUGH WILL LIFT NORTHEAST AND BRING BACK WARMER, MORE HUMID
CONDITIONS AND A RETURN TO DIURNAL CONVECTION BY THE MIDDLE OF
NEXT WEEK.
AVIATION /07Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: AN ACTIVE NEXT 24-30 HOURS EXPECTED ACROSS
THE AREA, AS ISOLATED TO SCATTERED CONVECTION MAY LINGER THRU
THE PRE-DAWN HOURS, ALONG WITH A POTENTIAL THUNDERSTORM CLUSTER
ENTERING THE WESTERN CAROLINAS FROM THE WEST IN THE 09Z-12Z TIME
FRAME. GUIDANCE HAS NOT BEEN HANDLING THIS ACTIVITY WELL, SO
CONFIDENCE REMAINS LOW, AND WILL JUST KEEP A VCSH MENTION AT KAVL
FOR THE EARLY MORNING. LATER TODAY, CONFIDENCE IS INCREASING ON
NUMEROUS TO WIDESPREAD SHRA AND TSRA, ESPECIALLY AROUND KCLT. WILL
GO WITH PREVAILING SHRA AND TEMPO TSRA AT KCLT. WILL KEEP TS IN
PROB30 ELSEWHERE. CONVECTION MAY LINGER INTO THE EVENING, WITH
HIGHEST CONFIDENCE OVER KCLT, SO WILL HAVE A PROB30 FOR MORE
TSRA THERE. WILL LEAVE OUT OF THE OTHER SITES FOR NOW. MVFR TO
IFR STRATUS MAY START DEVELOPING AFTER THE RAIN ENDS LATE THIS
EVENING ACROSS THE AREA, WITH MORE WIDESPREAD IFR CIGS POSSIBLE
AFTER 06Z TONIGHT. WINDS WILL BE QUITE VRB THRU THE PERIOD,
ESPECIALLY AROUND THUNDERSTORMS.
OUTLOOK: ISOLATED TO SCATTERED AFTERNOON SHRA/TSRA MAY DEVELOP
AGAIN SATURDAY. BY SUNDAY, A DRIER PATTERN SHOULD ARRIVE AND LAST
THROUGH THE FIRST HALF OF NEXT WEEK, POSSIBLY KEEPING SHRA/TSRA
TO A MINIMUM THOSE DAYS. MOUNTAIN VALLEY FOG AND LOW STRATUS WILL
BE POSSIBLE EACH MORNING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
ARK
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page