407
FXUS62 KGSP 200643
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
243 AM EDT MON JUL 20 2026
WHAT HAS CHANGED
BETTER CONVECTIVE CHANCES OVER NORTH CAROLINA TODAY. HOT AND HUMID
BUT HEAT INDEX VALUES NOT QUITE AS HIGH AS PREVIOUS DAYS.
KEY MESSAGES
1. ELEVATED HEAT INDEX VALUES CONTINUE THROUGH WEDNESDAY. COOLER
TEMPERATURES LATER IN THE WEEK SHOULD PROVIDE SOME RELIEF FROM
THE HEAT.
2. ANOTHER ROUND OF SCATTERED CONVECTION WITH A FEW SEVERE STORMS
POSSIBLE TODAY. LESS CONVECTIVE COVERAGE IS ANTICIPATED ON TUESDAY,
BUT A FEW SEVERE STORMS REMAIN POSSIBLE. A WEAK COLD FRONT BRINGS
INCREASED COVERAGE AND THE POTENTIAL FOR MORE SEVERE WEATHER
ON WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: ELEVATED HEAT INDEX VALUES CONTINUE THROUGH WEDNESDAY.
COOLER TEMPERATURES LATER IN THE WEEK SHOULD PROVIDE SOME RELIEF
FROM THE HEAT.
HIGHS REMAIN NEARLY STEADY IN THE LOW TO MID 90S OUTSIDE OF THE
MOUNTAINS TODAY AND TUESDAY. DEWPOINTS SHOULD MIX OUT ENOUGH TO KEEP
HEAT INDEX VALUES BELOW 105 FOR MOST LOCATIONS. THAT SAID, CAN'T
RULE OUT A SPOTTY BRIEF 105 VALUE ALONG AND SOUTH OF THE I-85
CORRIDOR EITHER DAY. TEMPS DO FALL A FEW DEGREES WEDNESDAY BUT
DEWPOINTS REMAIN ELEVATED. THIS KEEPS ELEVATED HEAT INDEX VALUES
ALONG AND SOUTH OF THE I-85 CORRIDOR. AGAIN, MOST LOCATIONS REMAIN
BELOW 105 BUT A SPOTTY BRIEF 105 IS POSSIBLE. AN AIRMASS CHANGE
TAKES PLACE BEHIND A COLD FRONT FOR THURSDAY AND FRIDAY. HIGHS
ACTUALLY END UP BELOW NORMAL, A WELCOME BREAK FROM THE RECENT HEAT
AND HUMIDITY. UNTIL THEN, STAY HYDRATED, TAKE FREQUENT BREAKS IN AIR-
CONDITIONED OR SHADED AREAS, AND NEVER LEAVE CHILDREN OR PETS
UNATTENDED IN VEHICLES.
KEY MESSAGE 2: ANOTHER ROUND OF SCATTERED CONVECTION WITH A FEW SEVERE
STORMS POSSIBLE TODAY. LESS CONVECTIVE COVERAGE IS ANTICIPATED ON
TUESDAY, BUT A FEW SEVERE STORMS REMAIN POSSIBLE. A WEAK COLD FRONT
BRINGS INCREASED COVERAGE AND THE POTENTIAL FOR MORE SEVERE WEATHER
ON WEDNESDAY.
A WEAK FRONTAL BOUNDARY STALLS OVER NC TODAY. THE CONVERGENCE ALONG
THE FRONT WILL KEEP BETTER CONVECTIVE CHANCES OVER NC. THE LATEST
CAMS KEEP NE GA AND THE UPSTATE MOSTLY DRY, WITH CHANCES MAINLY OVER
THE MOUNTAINS. THIS LOOKS REASONABLE GIVEN THE LOWER INSTABILITY AND
HIGHER LFC'S OVER THOSE AREAS. SHEAR IS LIMITED TODAY BUT THE AIR
MASS OVER NC IS VERY UNSTABLE WITH HIGH PW VALUES AND STEEP LOW
LEVEL LAPSE RATES. THIS KEEPS THE THREAT OF A FEW SEVERE STORMS IN
PLACE WITH DAMAGING WINDS THE MAIN THREAT. CONVECTIVE COVERAGE FOR
TUESDAY IS HIGHER ACROSS THE MOUNTAINS WHERE BETTER MOISTURE AND
INSTABILITY EXIST WITH THE WEAK FRONT WASHING OUT OR MOVING BACK
NORTHWARD. THE THREAT OF A FEW SEVERE STORMS WITH DAMAGING WINDS
CONTINUES. COVERAGE IS EXPECTED TO INCREASE AGAIN ON WEDNESDAY AS AN
UPPER TROF AMPLIFIES OVER THE EASTERN CONUS AND MOVES YET ANOTHER
COLD FRONT INTO OUR AREA. SEVERE STORM POTENTIAL MAY ALSO INCREASE
AGAIN ON WEDNESDAY WITH THE BETTER FORCING, MOISTURE CONVERGENCE,
AND BULK SHEAR TO GO ALONG WITH THE UNSTABLE AIRMASS. EVEN WITH THE
FRONT MOVING SOUTH OF THE AREA, MORE TYPICAL DIURNAL CONVECTION
CHANCES RETURN FOR THE END OF THE WEEK.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: CONVECTION ALONG A LINGERING OUTFLOW BOUNDARY
WILL KEEP TSRA NEAR OR OVER KCLT UNTIL 08Z BUT COULD MOVE OUT
EARLIER. HAVE INCLUDED A TEMPO FOR THIS. OTHERWISE, NO CONVECTION
EXPECTED AT THE REST OF THE SITES. CIRRUS IS CLEARING OUT OVER THE
WEST WITH SOME ALTOCU LINGERING OVER THE EASTERN SITES. MOUNTAIN
VALLEY FOG ALREADY DEVELOPING AND EXPECT IT TO SPREAD TO KAVL EARLY
THIS MORNING. HAVE MVFR TEMPO IFR THERE. SOME FOG ALSO POSSIBLE AT
KHKY, SO THEY ALSO HAVE MVFR TEMPO IFR. WITH A FRONTAL BOUNDARY
DRAPED ACROSS NC, EXPECT DIURNAL CONVECTION TO FIRE THERE, SO
PROB30S IN PLACE. THE GUIDANCE SHOWS LESS INSTABILITY AND FORCING
OVER SC. THE CAMS KEEP CONVECTION NORTH OF THE SC SITES, SO HAVE
REMOVED THE PROB30S THERE FOR NOW. LIGHT SW WIND PICKS UP DURING THE
DAY THEN BECOMES LIGHT OVERNIGHT. MOUNTAIN VALLEY FOG EXPECTED
AGAIN.
OUTLOOK: SHRA/TSRA MAY RETURN AGAIN TUE THOUGH MORE LIKELY
TO REMAIN NEAR THE NC MOUNTAINS THAT AFTERNOON AS COMPARED TO
MONDAY. COVERAGE IS EXPECTED TO INCREASE AGAIN ON WEDNESDAY AND
THURSDAY THEN DECREASE ON FRIDAY. LOW STRATUS AND/OR FOG WILL BE
POSSIBLE EACH MORNING, MAINLY IN THE MTN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
RWH
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