273
FXUS62 KGSP 311808
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
208 PM EDT MON AUG 31 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE PUBLIC FORECAST.
THE AVIATION FORECAST WAS UPDATED TO REFLECT THE 18Z TAF ISSUANCE.
KEY MESSAGES
1. HEAT AND HUMIDITY RETURN THIS WEEK. DANGEROUS TRIPLE DIGIT
HEAT INDEX VALUES ARE EXPECTED ACROSS MUCH OF THE LOW TERRAIN
EACH AFTERNOON.
2. SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON GIVE WAY
TO DRY CONDITIONS TUESDAY. THUNDERSTORM CHANCES STEADILY RETURN
INTO THE WEEKEND.
DISCUSSION
KEY MESSAGE 1: HEAT AND HUMIDITY RETURN THIS WEEK. DANGEROUS TRIPLE
DIGIT HEAT INDEX VALUES ARE EXPECTED ACROSS MUCH OF THE LOW TERRAIN
EACH AFTERNOON.
A BROAD UPPER ANTICYCLONE CENTERED OVER THE MID MS VALLEY WILL
SLOWLY MOVE EAST THROUGH THE WEEK BECOMING CENTERED OVER THE
SOUTHEAST BY THURSDAY. THIS BRINGS A QUICK INCREASE IN HEAT WITH
HIGHS IN THE MID TO UPPER 90S ACROSS MOST LOCATIONS OUTSIDE OF THE
MOUNTAINS, AND LOWER 90S IN THE WARMER MOUNTAIN VALLEYS, THROUGH
FRIDAY. DEWPOINTS WILL BE ON THE INCREASE AS WELL WITH VALUES IN THE
UPPER 60S TO LOWER 70S FOR MOST LOCATIONS OUTSIDE OF THE MOUNTAINS.
VALUES IN THE MID TO UPPER 60S IN THE WARMER MOUNTAIN VALLEYS WILL
ALSO BE COMMON. THIS IS EVEN WITH SOME SLIGHT MIXING DURING THE
AFTERNOONS. THE RESULT WILL BE HEAT INDEX VALUES INTO THE TRIPLE
DIGITS ACROSS MOST LOCATIONS OUTSIDE OF THE MOUNTAINS. A HEAT
ADVISORY LOOKS UNLIKELY FOR TUESDAY, BUT THE POTENTIAL INCREASES
THROUGH THE WEEK. EVEN IF AN ADVISORY ISN'T ISSUED, THERE WILL BE
THE POTENTIAL FOR HEAT-RELATED ILLNESSES TO OCCUR.
A WEEK COLD FRONT LOOKS TO CROSS THE AREA SATURDAY. THIS WOULD BRING
SOME RELIEF FOR THE WEEKEND INTO MONDAY. OF COURSE, TIMING IS
UNCERTAIN, SO WE'LL KEEP A HOPEFUL EYE ON IT.
KEY MESSAGE 2: SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON GIVE
WAY TO DRY CONDITIONS TUESDAY. THUNDERSTORM CHANCES STEADILY RETURN
INTO THE WEEKEND.
SCATTERED CONVECTION HAS DEVELOPED ACROSS THE MOUNTAINS AND WILL
MOVE SOUTH INTO THE FOOTHILLS AND POSSIBLY THE PIEDMONT. CAN'T RULE
OUT A ROUGE STRONG GUST GIVEN THE STEEP LOW LEVEL LAPSE RATES AND
DCAPE, BUT THE OVERALL THREAT OF ANY STRONG TO SEVERE STORMS IS VERY
LOW GIVEN THE WEAK MID LEVEL LAPSE RATES AND LACK OF ORGANIZATION.
THE CONVECTION SHOULD DIMINISH QUICKLY WITH LOSS OF HEATING.
NO SIGNIFICANT CHANCE OF CONVECTION TUESDAY AS THE BUILDING UPPER
ANTICYCLONE AND HIGH LFC VALUES SHOULD SUPPRESS ANY DEEP CONVECTION.
DESPITE THE ANTICYCLONE, CONVECTIVE POTENTIAL RETURNS ACROSS THE
MOUNTAINS WEDNESDAY THROUGH FRIDAY WHERE DIFFERENTIAL HEATING WILL
BE ENOUGH TO OVERCOME THE RELATIVELY HIGH LFC'S. THAT SAID, THE
RETURN COULD BE SLOWER IF THE LOW LEVEL HEATING IS STRONG ENOUGH TO
KEEP A STRONGER CAP IN PLACE. BETTER CHANCES FOR CONVECTION DEVELOP
THIS WEEKEND AS THE ANTICYCLONE WEAKENS AND A SHORTWAVE DIVES INTO
THE MID ATLANTIC AND PUSHES A FRONT INTO OUR AREA. ENOUGH DRY AIR
MAY MOVE INTO THE AREA BEHIND THE FRONT TO LIMIT CONVECTIVE CHANCES
TO THE MOUNTAINS ON MONDAY.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: LOW VFR CUMULUS CONTINUES THROUGH THE
AFTERNOON WITH LIGHT AND VARIABLE WIND. KAVL THE EXCEPTION WHERE
CONVECTION WILL BE NEARBY, AND POSSIBLY AT THE AIRFIELD, ALONG WITH
LOW END GUSTY NW WIND. HAVE INCLUDED A PROB30 THERE AND KHKY
WHERE CONVECTION ALSO MAY MOVE NEARBY. NO MENTION ELSEWHERE.
CUMULUS DISSIPATES THIS EVENING WITH WIND GENERALLY BECOMING CALM.
MOUNTAIN VALLEY FOG EXPECTED AGAIN, WITH MVFR FOG FOR NOW AT KHKY.
LIGHT NW WIND PICKS UP ON TUESDAY WITH VFR CUMULUS BUT NO
SIGNIFICANT CHANCE OF CONVECTION.
OUTLOOK: SCATTERED MOUNTAIN CONVECTION EXPECTED THROUGH FRIDAY THEN
ALL AREAS FOR THE WEEKEND. FOG AND LOW STRATUS WILL BE POSSIBLE EACH
MORNING, ESPECIALLY IN THE MOUNTAIN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
RWH
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