147
FXUS62 KGSP 231817
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
217 PM EDT TUE JUN 23 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 18Z TAFS.
VERY SLIGHT DOWNWARD TREND IN HIGH TEMPERATURES LATE IN THE PERIOD,
WITH INCREASING MOUNTAIN-AREA POPS FRIDAY INTO SATURDAY.
KEY MESSAGES
1. A SLOW-MOVING COLD FRONT WILL MOVE THROUGH THE AREA THIS
AFTERNOON, BRINGING A FEW SHOWERS AND POSSIBLY A COUPLE OF
THUNDERSTORMS TO THE I-77 CORRIDOR. BEHIND THE FRONT, SLIGHTLY
COOLER AND DRIER CONDITIONS ARE EXPECTED FOR WEDNESDAY.
2. DIURNAL SHOWER AND THUNDERSTORM CHANCES RETURN BY THE END OF THE
WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES OUTSIDE THE MOUNTAINS
ARE EXPECTED TO CLIMB INTO THE MID TO UPPER 90S THIS WEEKEND.
DISCUSSION
KEY MESSAGE 1: A SLOW-MOVING COLD FRONT WILL MOVE THROUGH THE AREA
THIS AFTERNOON, BRINGING A FEW SHOWERS AND POSSIBLY A COUPLE OF
THUNDERSTORMS TO THE I-77 CORRIDOR. BEHIND THE FRONT, SLIGHTLY
COOLER AND DRIER CONDITIONS ARE EXPECTED FOR WEDNESDAY.
A COLD FRONT HAS PUSHED THROUGH ALMOST THE ENTIRE FORECAST AREA THIS
MORNING, WITH NW BREEZY WINDS BEHIND THE FRONT. MUCH DRIER AND
SOMEWHAT COOLER AIR IS FILTERING IN, WITH THE WEAK CAA COMPETING
WITH DOWNSLOPING AND LATE JUNE SUN. ALONG THE I-77 CORRIDOR, THERE
REMAINS ENOUGH MOISTURE AND INSTABILITY UNDERNEATH THE UPPER TROUGH
TO TRIGGER SOME SHOWERS AND PERHAPS A COUPLE OF THUNDERSTORMS THIS
AFTERNOON, BUT ANY CONVECTION IS VERY LIMITED ON THE CAMS, AND
STRONG TO SEVERE STORMS ARE CERTAINLY NOT EXPECTED. NW FLOW AGAINST
THE MOUNTAINS CONTINUES TO BRING CLOUDS WITH MOUNTAIN WAVE ACTIVITY,
AND IN THE GAPS CLOUDS ARE MAKING THEIR WAY INTO THE FOOTHILLS AND
EVEN TOWARD THE PIEDMONT AS THE PRIMARY AREA OF LOW-LEVEL
MOISTURE/CLOUDS EXITS WITH THE FRONT. MAY SEE SOME BRIEF SHOWERS
WITH THE MECHANICAL UPLIFT IN THE MOUNTAINS INTO THIS EVENING, BUT
POPS SHOULD DIMINISH AS WE PUSH INTO OVERNIGHT.
TEMPERATURES TONIGHT THROUGH WEDNESDAY NIGHT WILL RUN A HANDFUL OF
DEGREES BELOW SEASONAL NORMALS FOR LOWS AND HIGHS, WITH MAINLY JUST
SOME PASSING CLOUDS IN THE GENERAL WEAKNESS ALOFT.
KEY MESSAGE 2: DIURNAL SHOWER AND THUNDERSTORM CHANCES RETURN BY THE
END OF THE WEEK AND INTO THE WEEKEND. HIGH TEMPERATURES OUTSIDE THE
MOUNTAINS ARE EXPECTED TO CLIMB INTO THE MID TO UPPER 90S THIS
WEEKEND.
WEAK TROUGHINESS WILL BE IN PLACE IN THE UPPER FLOW WITH RIDGING
ACROSS THE DESERT SOUTHWEST AND THE ATLANTIC LATE IN THE WORK WEEK.
MOIST SOUTHERLY FLOW WILL RETURN TO THE SOUTHEAST STARTING THURSDAY,
AND AS THE ATLANTIC RIDGE BACKBUILDS INTO THE SOUTHEAST, HEIGHTS AND
CORRESPONDING THICKNESSES WILL RISE AGAIN. EACH DAY THURSDAY THROUGH
SUNDAY WILL SEE AN INCREMENTAL INCREASE IN AFTERNOON HIGHS, WITH
PIEDMONT TEMPERATURES OVER THE THREE-DAY PERIOD SATURDAY THROUGH
MONDAY RANGING FROM THE MID TO IN SOME CASES UPPER 90S. LATEST NBM
GUIDANCE HAS COME IN A TOUCH COOLER VS PREVIOUS FORECAST ESPECIALLY
ALONG THE I77 CORRIDOR ON MONDAY (IT'S ALL RELATIVE, MAYBE 96
INSTEAD OF 98), BUT STILL DEWPOINTS HIGH ENOUGH TO HAVE WIDESPREAD
HEAT INDICES AROUND OR JUST ABOVE 100 DEGREES. CANNOT RULE OUT HEAT
ADVISORY CONDITIONS ACROSS SOME OF THE AREA DEPENDING ON HOW MUCH
DEWPOINTS MIX OUT EACH AFTERNOON AND ANY ADDITIONAL CHANGES TO
TEMPERATURE TRENDS. THE INCREASED MOISTURE WILL BRING BACK THE
DIURNAL CONVECTIVE TREND, WITH BEST CHANCES ESPECIALLY FRIDAY AND
SATURDAY AFTERNOONS ALONG THE TN BORDER COUNTIES.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
AT KCLT AND ELSEWHERE: VFR CU WILL CONTINUE TO PUSH EAST WITH THE
COLD FRONT, THOUGH LINGERING MOUNTAIN CU MAY OCCASIONALLY IMPACT
KAVL THROUGH THE AFTERNOON. OTHERWISE, MAINLY A WIND FORECAST WITH N-
NNW WINDS TO START THE PERIOD GUSTING TO NEAR 20K, DIMINISHING THIS
EVENING INTO THE OVERNIGHT HOURS. AS HIGH PRESSURE APPROACHES FROM
THE WEST, WINDS WILL TREND MORE NNE TO LGT/VRB BY WEDNESDAY.
OUTLOOK: MOSTLY DRY, VFR CONDITIONS EXPECTED THROUGH THURSDAY.
DIURNAL SHOWER AND THUNDERSTORM CHANCES INCREASE AGAIN ON FRIDAY AND
CONTINUE THROUGH THE WEEKEND, BRINGING ASSOCIATED RESTRICTIONS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
TDP
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