557
FXUS62 KGSP 212321
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
721 PM EDT SUN JUN 21 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION.
KEY MESSAGES
1. DRY TODAY BEFORE A COLD FRONT BRINGS SHOWER AND THUNDERSTORM
CHANCES BACK MONDAY INTO TUESDAY. SEVERE STORMS REMAIN POSSIBLE
MONDAY AFTERNOON INTO LATE MONDAY EVENING, WITH DAMAGING WINDS
BEING THE MAIN HAZARD.
DISCUSSION
KEY MESSAGE 1: DRY TODAY BEFORE A COLD FRONT BRINGS SHOWER AND
THUNDERSTORM CHANCES BACK MONDAY INTO TUESDAY. SEVERE STORMS REMAIN
POSSIBLE MONDAY AFTERNOON INTO LATE MONDAY EVENING, WITH DAMAGING
WINDS BEING THE MAIN HAZARD.
DRY TODAY WITH SURFACE HIGH PRESSURE REMAINING OVERHEAD. THE 12Z
CAMS SHOW THE POTENTIAL FOR SOME ISOLATED CONVECTION TO DEVELOP LATE
THIS AFTERNOON SOUTH OF I-85 AND WEST OF I-26 BUT KEEP MOST OF THE
ACTIVITY JUST SOUTH AND WEST OF THE GSP CWA. IT WILL BE WARMER TODAY
AND SLIGHTLY MORE HUMID COMPARED TO YESTERDAY. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP OVERNIGHT INTO EARLY MONDAY MORNING
ACROSS THE SOUTHERN NORTH CAROLINA MOUNTAINS, NORTHEAST GEORGIA, AND
THE FAR NORTHWESTERN SOUTH CAROLINA UPSTATE. THIS ACTIVITY IS NOT
EXPECTED TO BE SEVERE AND SHOULD DISSIPATE BY MID-MORNING.
BETTER SHOWER AND THUNDERSTORM CHANCES RETURN MONDAY AFTERNOON AND
EVENING AS A LINE OF STORMS DEVELOPS AHEAD OF A COLD FRONT. WITH 12Z
HIGH-RES GUIDANCE DEPICTING 20-25 KTS OF DEEP LAYER SHEAR AVAILABLE
AHEAD OF THE FRONT AND 1,500-2,200+ J/KG OF SBCAPE DEVELOPING DURING
PEAK HEATING HOURS MONDAY, STRONG TO SEVERE STORMS ARE POSSIBLE. THE
MAIN HAZARD STILL APPEARS TO BE DAMAGING WIND GUSTS. LATEST HIGH-RES
TRENDS HAVE THE MAIN LINE TRACKING A BIT SLOWER, WITH TIMING FOR
SEVERE STORMS NOW LOOKING TO BE ~4 PM TO MIDNIGHT. SCATTERED SHOWERS
AND THUNDERSTORMS MAY DEVELOP AHEAD OF THE MAIN LINE ACROSS THE
NORTH CAROLINA FOOTHILLS AND PIEDMONT MONDAY AFTERNOON SO THESE
LOCATIONS MAY SEE THE SEVERE THREAT DEVELOP A BIT EARLIER. ALTHOUGH
SPC EXPANDED THE THE DAY 2 SLIGHT RISK ACROSS NEARLY THE ENTIRE GSP
CWA, CONFIDENCE ON THE SEVERE THREAT EAST OF THE MOUNTAINS IS LOW AS
ACTIVITY WILL NOT PUSH OFF THE MOUNTAINS UNTIL AFTER PEAK HEATING
AND AS THE 12Z CAMS SHOW ACTIVITY GRADUALLY WEAKENING THROUGH THE
EVENING AS A RESULT. CONFIDENCE ON THE DAMAGING WIND RISK IS HIGHER
ACROSS THE MOUNTAINS AND ALONG AND NORTH OF I-40 WHERE ACTIVITY WILL
DEVELOP DURING PEAK HEATING HOURS. BREEZY SW WINDS CAN ALSO BE
EXPECTED AHEAD OF THE FRONT ON MONDAY, ESPECIALLY EAST OF THE
MOUNTAINS WHERE GUSTS WILL RANGE FROM 20-30 MPH (WELL BELOW ADVISORY
CRITERIA). ANY LINGERING ACTIVITY WILL GRADUALLY PUSH SOUTH AND EAST
OF THE FORECAST AROUND OR SHORTLY AFTER MIDNIGHT, ALLOWING DRIER
CONDITIONS TO RETURN FOR MOST LOCATIONS. HOWEVER, NW FLOW RAIN
SHOWERS MAY DEVELOP ALONG THE NC/TN BORDER BEHIND THE FRONT MONDAY
NIGHT, LINGERING THROUGH AT LEAST TUESDAY MORNING.
SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP AGAIN TUESDAY
AFTERNOON/EARLY EVENING RIGHT ALONG THE FRONT (MAINLY ACROSS THE
SOUTH CAROLINA UPSTATE) BUT CONFIDENCE IS LOW. AS A RESULT OF THIS
POTENTIAL, THE LATEST NBM HAS TRENDED UPWARD SLIGHTLY COMPARED TO
THE PREVIOUS FORECAST REGARDING POPS TUESDAY AFTERNOON/EVENING EAST
OF THE MOUNTAINS BUT AGAIN CONFIDENCE IS LOW.
AVIATION /00Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS PREVAIL AT ALL TERMINALS
THROUGH THE MAJORITY OF THE TAF PERIOD. HIGHER CLOUDS AND LIGHT TO
CALM WINDS OVERNIGHT BEFORE PICKING UP AGAIN OUT OF THE SW MONDAY
MORNING. AHEAD OF A FRONT, WINDS INCREASE ACROSS MOST SITES EAST OF
THE MOUNTAINS BY MONDAY AFTERNOON WITH GUSTS OF 15-25KTS LIKELY.
TSRA CHANCES INCREASE WITH THE FRONT FOR ALL SITES, SO A PROB30
EVERYWHERE FOR MONDAY AFTERNOON. LINGERING TSRA/SHRA IS POSSIBLE
AFTER 23Z AT KCLT.
OUTLOOK: BRIEF PERIOD OF DRY CONDITIONS BEHIND A COLD FRONT BEFORE
DAILY SHOWER AND THUNDERSTORM CHANCES RETURN BY MIDWEEK AND INTO THE
WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
AR/CP
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