091
FXUS62 KGSP 211041
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
641 AM EDT Tue Jul 21 2026

.WHAT HAS CHANGED...
Updated the aviation discussion for the 12Z TAFs.

&&

.KEY MESSAGES...
1. Elevated heat index values continue today. Cooler temperatures
later in the week should provide some relief from the heat.
2. Convection today limited to the NC mountains and foothills,
but a few severe storms are possible. A weak cold front brings
increased coverage and the potential for more severe weather on
Wednesday. The front slowly moves south Thursday with elevated
convective coverage but a lower severe weather chance.

&&

.DISCUSSION...
Key message 1: Elevated heat index values continue today. Cooler
temperatures later in the week should provide some relief from the
heat.

High temperatures will be in the low to mid 90s outside of the
mountains today. Dewpoints should mix out enough to keep heat index
values below 105 degrees for most locations. However, they will rise
above 100 along and south of the I-85 corridor. Still, can`t rule
out a few brief values of 105 in that area. With more clouds and
increased convective chances Wednesday, high will be slightly below
normal. Dewpoints remain elevated as they won`t mix out as much, but
with the lower temps, heat index values will be below 100 for all
but the lower Piedmont. All areas will finally see relief from the
heat Thursday through Saturday as a cooler air mass builds in as a
cold front moves south of the area. In fact, highs will be up to 10
degrees below normal. Until then, stay hydrated, take frequent
breaks in air-conditioned or shaded areas, and never leave children
or pets unattended in vehicles. Heat and humidity return early next
week with temps back around normal.


Key message 2: Convection today limited to the NC mountains and
foothills, but a few severe storms are possible. A weak cold front
brings increased coverage and the potential for more severe weather
on Wednesday. The front slowly moves south Thursday with elevated
convective coverage but a lower severe weather chance.

CAM guidance continues to shower lower convective coverage across
the area today. Best chances will be over the NC mountains and
foothills. A more capped atmosphere with high LFC`s remain south of
there limiting the chance of convection. A few severe storms are
possible with a very moist and unstable air mass with steep low
level lapse rates. Isolated convection may linger there overnight as
a weakening line of convection moves south from the OH Valley.

A weak cold front settles over the area Wednesday bringing
increasing convergence and better forcing. Expect increased coverage
of convection during the afternoon and evening. A few severe storms
remain possible given the instability and forcing along with an
increase in bulk shear. The isolated flood threat increases as well
with slow moving and likely training storms as the boundary slowly
moves south. Convective coverage remains high on Thursday as the
front continues to lowly dag southward. However, the severe threat
will be lower as instability weakens. An isolated flood threat will
remain with slow moving and possibly training cells in a very moist
air mass.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Mountain valley fog dissipating with low VFR
stratocu in place. Cirrus spread over the area with increasing VFR
Cu into the afternoon. Convective coverage is expected to be lower
than previous days, so no PROB30s for now. S to SW winds pick up
speed through the day with gusts developing by afternoon. Gusts
diminish during the evening, but speeds remain elevated. Mountain
valley fog is possible overnight, but chance too low for the KAVL
TAF for now.

Outlook: SHRA/TSRA coverage is expected to increase on Wednesday and
Thursday as a front settles southward through the area. At least
scattered diurnal convection expected Friday and Saturday. 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