897
FXUS62 KGSP 050035
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
835 PM EDT TUE AUG 4 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 00Z TAFS.
KEY MESSAGES
1. ABOVE-AVERAGE RAIN CHANCES AND BELOW NORMAL TEMPERATURES
CONTINUE THROUGH WEDNESDAY.
2. A MORE TYPICAL LATE SUMMER PATTERN RETURNS THURSDAY,THOUGH
TEMPERATURES REMAIN SLIGHTLY BELOW NORMAL AND DAILY CHANCES FOR
SHOWERS AND STORMS WILL REMAIN ELEVATED THROUGH SATURDAY.
TEMPERATURES AND PRECIPITATION CHANCES RETURN TO AROUND NORMAL
SUNDAY AND MONDAY.
DISCUSSION
KEY MESSAGE 1: ABOVE-AVERAGE RAIN CHANCES AND BELOW NORMAL
TEMPERATURES CONTINUE THROUGH WEDNESDAY.
AN UPPER LOW IS CENTERED OVER NORTHERN GEORGIA AS OF 2 PM TUE WILL
DRIFT SLOWLY NORTHWARD THROUGH WEDNESDAY, PROMOTING EASTERLY FLOW
IN THE LOW- TO MID-LEVELS, WHICH HAS BROUGHT A PLUME OF ENHANCED
PWATS FROM THE ATLANTIC INTO WESTERN NC AND THE EASTERN UPSTATE,
THOUGH THE REMAINDER OF THE CWA REMAINS MOIST AT THE SURFACE
DESPITE DRY AIR BEING PRESENT ALOFT WITHIN THE CYCLONE. LCLS ARE
LOW, AND 700-500MB LAPSE RATES ARE A LITTLE BETTER THAN USUAL, SO
WITH DIURNAL HEATING ALREADY HAVING PRODUCED 2000+ J/KG SBCAPE,
A BROAD AREA OF SHOWERS WITH EMBEDDED STORMS HAS ALREADY BECOME
ESTABLISHED, CENTERED ON THE PIEDMONT. STORM MOTION HAS BEEN SLOW
AND A NUMBER OF OBS SITES HAVE RECEIVED A QUICK 1 TO 2 INCHES
OF RAIN. WE WILL BE CLOSELY MONITORING FOR POTENTIAL LOCALIZED
FLASH FLOODING. DCAPE IS STRONGEST NEAR THE CORE OF THE LOW, OVER
THE WESTERN UPSTATE AND NE GA, AND AN ISOLATED SEVERE MICROBURST
THREAT DOES EXIST PARTICULARLY IN THAT AREA. WHAT STEERING FLOW
THERE IS SHOULD GENERALLY PUSH THE CONVECTION TOWARD THE NORTH
OR NORTHWEST. CAMS LARGELY DEPICT THE ACTIVITY PROPAGATING IN
THAT DIRECTION BUT VARY AS TO WHETHER A SECOND ROUND DEVELOPS IN
THE WAKE OF THE CURRENT ACTIVITY. WHILE OUTFLOWS HAVE LED TO SOME
POCKETS OF STABILIZATION, THE EARLY START, SOUPY DEWPOINTS IN THE
LOWER 70S, AND STRONG ANVIL-LEVEL FLOW SUGGESTING A RELATIVELY LOW
CHANCE THAT CIRRUS WILL FILL IN AND PRECLUDE REDEVELOPMENT. THUS
WE RETAIN AT LEAST 20-40% POPS UNTIL MIDNIGHT OVER MUCH OF THE
PIEDMONT. EASTERLY NEAR-SURFACE FLOW SUGGESTS STRATUS MAY ADVECT
IN FROM THE ATLANTIC TOWARD DAYBREAK, BUT RADIATION FOG/STRATUS
COULD ALSO OCCUR WITH SO MUCH OF THE AREA GETTING SOAKED THIS
AFTERNOON AND SFC WINDS BEING LIGHT TONIGHT.
WEDNESDAY, THE UPPER LOW FILLS AND IS REABSORBED INTO
THE WESTERLIES. SURFACE WINDS FAVOR SOUTHERLY AGAIN; PWATS
INCREASE ACROSS THE BOARD WITH THE DRYING EFFECT OF THE UPPER
LOW NO LONGER BEING A FACTOR. IN GENERAL THIS DISTRIBUTES POPS
MORE CLIMATOLOGICALLY, WITH THE GREATEST VALUES BEING OVER THE
MOUNTAINS/FOOTHILLS. LAPSE RATES JUST ABOVE THE BOUNDARY LAYER ARE
SLIGHTLY BETTER, AND WITH THE HIGHER PWATS ABOVE-CLIMO CHANCES
ARE WARRANTED (50-80% IN MUCH OF THE CWA). 500MB WINDS WILL BE
STRONGER WHICH MAY RESULT IN A LITTLE BETTER 0-6KM BULK SHEAR,
BUT DCAPE SHOULD BE LOWER, SO THAT WILL HELP MITIGATE ANY DAMAGING
WIND THREAT. STORMS MAY JUST HAVE A SLIGHTLY BETTER CHANCE OF
FORMING INTO CLUSTERS.
IN THE SOUTHERLY FLOW REGIME, TEMPS WEDNESDAY INCH BACK INTO
THE MID-80S OVER MOST OF THE PIEDMONT, PARTICULARLY SOUTH OF
I-85. HOWEVER ALL VALUES SHOULD REMAIN A BIT BELOW NORMAL.
KEY MESSAGE 2: A MORE TYPICAL LATE SUMMER PATTERN RETURNS THURSDAY,
THOUGH TEMPERATURES REMAIN SLIGHTLY BELOW NORMAL AND DAILY CHANCES
FOR SHOWERS AND STORMS WILL REMAIN ELEVATED THROUGH SATURDAY.
TEMPERATURES AND PRECIPITATION CHANCES RETURN TO AROUND NORMAL
SUNDAY AND MONDAY.
FOLLOWING THE DISSOLUTION OF THE UPPER LOW, OUR WEATHER PATTERN
RETURNS TO BEING MORE TYPICAL FOR THIS TIME OF YEAR; THAT IS TO
SAY, BECOMING MORE ILL-DEFINED. PWAT VALUES FROM THE GFS AND ECMWF
ENSEMBLES REMAIN JUST ON THE WET SIDE OF CLIMO. DIURNAL INSTABILITY
WILL REMAIN THE PRIMARY DRIVER OF SHOWER/THUNDERSTORM CHANCES,
AND AN UPWARD TREND IN SBCAPE GENERALLY LOOKS TO OCCUR THURSDAY
AND FRIDAY, WITH VALUES REMAINING SIMILAR OR MARGINALLY HIGHER ON
SATURDAY. A LONGWAVE TROUGH SLOWLY MOVES ACROSS THE MISSISSIPPI
VALLEY INTO THE GREAT LAKES REGION WHILE THE BERMUDA HIGH REMAINS
STRONG IN THE WESTERN ATLANTIC. THIS WILL REINFORCE A SOUTHERLY
LOW-LEVEL FLOW REGIME AND ABOVE-CLIMO POPS ACROSS THE AREA, WITH
70-80% CHANCES EACH DAY OVER THE MOUNTAINS AND 30-50% FOR THE
PIEDMONT. SHEAR WILL BE WEAK, AND A MARGINALLY SEVERE MICROBURST
CAN'T BE RULED OUT ANY DAY, THOUGH THE DAMAGING WIND THREAT
DOES NOT LOOK PARTICULARLY NOTABLE. BY SUNDAY THE AFOREMENTIONED
TROUGH LOOKS TO HAVE FLATTENED OUT AND/OR SHIFTED EAST SUCH THAT
HEIGHT RISES OCCUR IN THE OHIO VALLEY, AND LOW-LEVEL FLOW TURNS
MORE WESTERLY AGAIN. HENCE, POPS FALL BACK TO A MORE TYPICAL
30-60% FOR THE MOUNTAINS AND 10-30% FOR THE PIEDMONT THAT DAY
AND MONDAY. TEMPS TREND BACK TO NEAR NORMAL, WITH LOWER PIEDMONT
LOCATIONS FLIRTING WITH 90 SUNDAY AND MOST PIEDMONT AREAS RISING
INTO THE LOWER 90S MONDAY.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: WE'VE STILL GOT CLUSTERS OF SLOW-MOVING
SHOWERS AND THUNDERSTORMS ACROSS OUR FCST AREA THIS EVENING.
THIS ACTIVITY IS LIKELY TO LINGER THROUGH THE LATE EVENING AND
POSSIBLY INTO THE OVERNIGHT IN SOME AREAS. AS SUCH, I HAVE VCTS
AT MOST TERMINALS THRU LATE TONIGHT WITH A TEMPO FOR TSRA AT KCLT
UNTIL 02Z. ELY ONSHORE FLOW IS EXPECTED TO BRING LOWER STRATUS
OVER KCLT/KHKY AND PROBABLY THE UPSTATE TERMINALS, HOWEVER THE
UPSTATE TERMINALS AND KAVL MAY ALSO DEVELOP RADIATION FOG. THUS,
I HAVE RESTRICTIONS DEVELOPING BY ROUGHLY 06Z AT MOST SITES, WITH
TEMPOS FOR LOWER RESTRICTIONS IN THE 08 TO 12Z TIMEFRAME FOR THE
UPSTATE SITES AND KHKY. CIGS WILL BE SLOW TO LIFT/SCT TOMORROW
MORNING, WITH SOME SITES NOT SEEING VFR CONDITIONS UNTIL 16 OR
17Z. WINDS SHOULD GO LIGHT AND VRB TO CALM LATER THIS EVENING AND
REMAIN THAT WAY THRU TOMORROW MORNING. THEY WILL PICK UP FROM THE
SE TO S TOMORROW AFTN, BECOMING MORE SLY AS THE DAY PROGRESSES.
ALL SITES GET A PROB30 FOR TSRA BEGINNING AROUND 18Z TOMORROW,
WITH OVERALL CONVECTIVE COVERAGE EXPECTED TO BE LESS THAN IT WAS
TODAY.
OUTLOOK: SCATTERED, DIURNAL SHOWERS AND THUNDERSTORMS WILL CON-
TINUE THROUGH THE REMAINDER OF THE WEEK, WITH ASSOCIATED FLIGHT
RESTRICTIONS. PATCHY FOG AND LOW STRATUS WILL BE POSSIBLE EACH
MORNING, ESPECIALLY IN THE MTN VALLEYS AND ANYWHERE THAT RECEIVED
SIGNIFICANT RAINFALL THE PREVIOUS DAY/EVENING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JCW/JPT
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