026
FXUS62 KGSP 251824
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
224 PM EDT THU JUN 25 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 18Z TAFS. OTHERWISE, NO
SIGNIFICANT CHANGES.
KEY MESSAGES
1. AFTERNOON/EVENING SHOWER AND THUNDERSTORM CHANCES RETURN
TOMORROW AND CONTINUE THROUGH THE WEEKEND, WITH ISOLATED SEVERE
STORMS POSSIBLE SATURDAY.
2. HOW WEATHER IS FORECAST TO ESCALATE DURING THE NEW WORK WEEK,
WITH TRIPLE DIGIT HEAT INDICES POSSIBLE ACROSS MOST OF OUR LOWER
TERRAIN BY MID-WEEK.
DISCUSSION
KEY MESSAGE 1: AFTERNOON/EVENING SHOWER AND THUNDERSTORM CHANCES
RETURN TOMORROW AND CONTINUE THROUGH THE WEEKEND, WITH ISOLATED
SEVERE STORMS POSSIBLE SATURDAY.
THE AIR MASS REMAINS RELATIVELY DRY FOR EARLY SUMMER ACROSS THE
FORECAST AREA THIS AFTERNOON, RESULTING IN WEAK-AT-MOST INSTABILITY
AND THEREFORE LITTLE-TO-NO CHANCE FOR DIURNAL CONVECTION. SEASONAL
TEMPERATURES ARE EXPECTED THROUGH FRIDAY, WITH SOME FOG/LOW STRATUS
AGAIN EXPECTED TO DEVELOP LATE TONIGHT IN THE MOST FAVORABLE
MOUNTAIN VALLEY LOCATIONS. LOW LEVEL S/SW FLOW WILL CONTINUE TO
BECOME ESTABLISHED OVER THE REGION IN RESPONSE TO UPSTREAM HEIGHT
FALLS, WITH MOISTURE ADVECTION EXPECTED TO RAMP UP LATE TONIGHT
INTO EARLY FRIDAY. THIS SHOULD ALLOW FOR MODEST DESTABILIZATION
AND DIURNAL CONVECTIVE DEVELOPMENT ACROSS THE CWA FRIDAY AFTERNOON,
WITH MOSTLY 30-40 POPS ADVERTISED.
HEIGHT FALLS/WEAK UPPER TROUGHING ARE FORECAST TO IMPACT THE EAST
ON SATURDAY, WITH AN ASSOCIATED SURFACE BOUNDARY EXPECTED TO FOCUS
INCREASED CONVECTIVE COVERAGE DURING THE AFTERNOON. SATURDAY POPS
RANGE FROM 50-70% ACROSS MUCH OF WESTERN NC, TO 20-40% ACROSS THE
REMAINDER OF THE CWA. STRONG HEATING...MAX TEMPS FORECAST TO BE A
COUPLE OF DEGREES ABOVE CLIMO...AND ELEVATED MOISTURE IS FORECAST
TO RESULT IN AT LEAST MODERATE INSTABILITY. WIND FIELDS WILL
REMAIN GENERALLY WEAK, BUT LOW LEVEL SHEAR MAY PROVE ADEQUATE TO
PROMOTE SOME CELL CLUSTERING ALONG OUTFLOWS. THIS ALONG WITH BETTER
COVERAGE AND INCREASED INSTABILITY WILL PROMOTE THE POTENTIAL FOR
A FEW ISOLATED SEVERE STORMS.
THE FLOW ALOFT WILL BECOME INCREASINGLY ANTICYCLONIC OVER
THE REGION LATE IN THE WEEKEND, AS HEIGHTS RISE STRONGLY IN
ASSOCIATION WITH A STRENGTHENING ANTICYCLONE CENTERED OVER THE
LOWER MISS VALLEY. NEVERTHELESS, FORECAST PROFILES AGAIN BECOME
FAVORABLE FOR DEEP CONVECTION SUNDAY AFTERNOON, ALTHOUGH COVERAGE
IS EXPECTED TO BE LESS THAN ON SATURDAY (MOSTLY 30-40 POPS) IN
LIGHT OF THE DEVELOPING UNFAVORABLE UPPER AIR PATTERN. TEMPERATURES
WILL OTHERWISE CONTINUE TO CLIMB UNDER RISING HEIGHTS, WITH SUNDAY
FORECAST MAXES AROUND 5 DEGREES ABOVE NORMAL. THIS IS EXPECTED TO
YIELD PEAK HEAT INDICES AT OR JUST ABOVE 100 ACROSS THE SOUTHERN
FRINGE OF THE CWA.
KEY MESSAGE 2: HOW WEATHER IS FORECAST TO ESCALATE DURING THE NEW
WORK WEEK, WITH TRIPLE DIGIT HEAT INDICES POSSIBLE ACROSS MOST OF
OUR LOWER TERRAIN BY MID-WEEK.
AN ANTICYCLONE WILL REMAIN THE MOST PROMINENT FEATURE IMPACTING THE
SOUTHEAST AND MID-ATLANTIC DURING THE NEW WORK WEEK, RESULTING IN
INCREASINGLY HOT CONDITIONS ACROSS OUR FORECAST AREA AS THE WEEK
PROGRESSES. FORECAST TEMPS BEGIN THE WEEK AROUND 5 DEGREES ABOVE
NORMAL...WARMING TO ALMOST 10 DEGREES ABOVE CLIMO BY THURSDAY...WHEN
SOME PIEDMONT LOCATIONS COULD SEE AMBIENT TEMPERATURES REACH THE
CENTURY MARK. RELATIVELY DRY AIR ALOFT AND A SUBSIDENT REGIME SHOULD
PROMOTE SOME DEGREE OF SURFACE DEWPOINT MIXING DURING EACH
AFTERNOON...BUT MAXIMUM HEAT INDICES ARE FORECAST TO REACH AROUND
100 ACROSS THE PIEDMONT WEDNESDAY. NEXT THURSDAY APPEARS TO BE THE
MOST LIKELY DAY FOR HEAT ADVISORY CRITERIA TO BE MET...MAINLY ACROSS
THE LAKELANDS AREA AS WELL AS THE I-77 CORRIDOR. CONDITIONS WILL
GENERALLY BE UNFAVORABLE FOR DEEP CONVECTION, BUT WE ARE NOW IN THE
TIME OF YEAR IN WHICH IT IS DIFFICULT TO NOT GET AT LEAST A FEW
AFTERNOON SHOWERS TO POP OVER THE HIGH TERRAIN. POPS ARE THEREFORE
PRIMARILY LIMITED TO THE MOUNTAINS EACH AFTERNOON MONDAY-THURSDAY,
AND EVEN THOSE CHANCES ARE CAPPED AT 20-30%.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR/CONVECTION-FREE WEATHER IS FORECAST AT
THE TAF SITES THROUGH AT LEAST FRIDAY MORNING, AS THE AIR MASS
OVER THE REGION WILL REMAIN RELATIVELY DRY FOR LATE JUNE. CAN'T
RULE OUT SOME LOW STRATUS AND/OR FOG DEVELOPING AT KAVL EARLY FRI
MORNING, BUT LIKE THIS MORNING, THE GREATER POTENTIAL FOR THIS WILL
BE IN THE MOUNTAIN VALLEYS WEST THROUGH NORTH OF KAVL. OTHERWISE,
GENERALLY LIGHT SW WINDS WITH FEW/SCT CUMULUS IN THE 050-060 RANGE
THIS AFTERNOON. WINDS BECOMING CALM OR LIGHT/VRBL THIS EVENING,
THEN LIGHT SW AGAIN LATE FRI MORNING. THE CONVECTIVE POTENTIAL
WILL BE HIGHER FRI AFTERNOON...AND A PROB30 FOR TSRA IS INCLUDED
AT KCLT AFTER 18Z.
OUTLOOK: AFTERNOON/EVENING SHOWER AND THUNDERSTORM CHANCES AND
ASSOCIATED RESTRICTIONS CONTINUE THROUGH THE WEEKEND. DIURNAL
CONVECTIVE CHANCES DIMINISH A BIT EARLY IN THE NEW WORK WEEK,
AS UPPER LEVEL HIGH PRESSURE STRENGTHENS OVER THE REGION. EARLY
MORNING FOG/LOW STRATUS IS POSSIBLE EACH DAY, ESPECIALLY IN THE
MOUNTAIN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JDL
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