826
FXUS62 KGSP 041021
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
621 AM EDT Fri Sep 4 2026

.WHAT HAS CHANGED...
A Heat Advisory was issued for Mecklenburg, Cabarrus, and Union
Counties in North Carolina from 11 AM to 8 PM EDT.

SPC removed the Marginal Risk for severe weather from the GSP
forecast area for today.

&&

.KEY MESSAGES...
1. Hot and humid conditions persist through Saturday, with heat
indices each afternoon ranging from the upper 90s to lower 100s
east of the mountains. Cooler and less humid conditions finally
return behind a cold front starting Sunday.
2. A strong cold front brings better coverage of showers and
thunderstorms over the holiday weekend. The main day of concern
for severe weather is Saturday during the afternoon and evening
hours. Drier conditions should return for much of next week.

&&

.DISCUSSION...
Key message 1: Hot and humid conditions persist through Saturday, with
heat indices each afternoon ranging from the upper 90s to lower 100s
east of the mountains. Cooler and less humid conditions finally
return behind a cold front starting Sunday.

Upper ridging remains over the central and southern United States
through Saturday keeping hot and humid conditions around. Heat
indices each afternoon will climb into the upper 90s to lower 100s
east of the mountains. A Heat Advisory was issued for Mecklenburg,
Cabarrus, and Union Counties in North Carolina for today from 11 AM
to 8 PM as heat indices are expected to reach advisory criteria.
Elsewhere, dewpoints should mix out enough to keep heat advisory
criteria at bay. Similar conditions are expected on Saturday but
confidence is low regarding another Heat Advisory as dewpoints will
mix out again and we will have the potential for better coverage of
convection east of the mountains which could further limit heat
indices.

Upper ridging retreats westward as upper troughing digs southward
towards the Carolinas Saturday into Sunday, with upper troughing
lingering over the region through Monday. This will allow a cold
front to track across the GSP forecast area late Saturday into early
Sunday morning, allowing for the return of cooler temperatures
starting Sunday. Monday looks to be the coolest day of the week
thanks to surface high pressure building into the region from the
north behind the front. Temperatures will then gradually warm again
Tuesday onward as yet another large upper anticyclone builds over
the southern and eastern United States. Thankfully, both dewpoints
and temperatures appear to be lower with this next anticyclone which
is nice as we can all agree that we need a break from the heat and
humidity (it is September after all). Unfortunately, fall does not
officially start until September 22.


Key message 2: A strong cold front brings better coverage of showers
and thunderstorms over the holiday weekend. The main day of concern
for severe weather is Saturday during the afternoon and evening
hours. Drier conditions should return for much of next week.

Main change this update is that the Day 1 SPC Marginal Risk for
severe weather was removed from the GSP CWA. This makes sense as the
severe threat looks better to our north and east. However, per
usual, can never rule out a rogue severe storm this time of year but
the chance is very low. coverage of convection will be slightly
better this afternoon and evening compared to yesterday but will
still be mainly focused over the mountains. Some activity may break
containment of the mountains but the 00Z CAMs are in agreement that
any activity that manages to push off the mountains will gradually
fall apart near the I-85 corridor. So if you are hoping for Mother
Nature to water your garden and lawn today (like a certain
forecaster) keep your expectations low, especially if you live south
of I-85.

Shower and thunderstorm chances will gradually increase over the
holiday weekend, with a cold front bringing the potential for strong
to severe storms Saturday afternoon and evening. The Day 2 SPC
Severe Weather Outlook continues to highlight a Slight Risk (level 2
out of 5) for most areas along and east of I-26. The placement of
the slight risk appears plausible as 15-20 kts of 0-6 km shear and
1,500-2,500 J/kg of SBCAPE will be available ahead of and along the
cold front Saturday afternoon/evening per the 00Z CAMs. A Marginal
Risk (level 1 out of 5) is in place for most locations west of I-26
with the exception of northeast Georgia (as 00Z CAMs show very
little in the way of activity Saturday afternoon/evening). 00Z CAMs
show two rounds of convection developing, one Saturday afternoon and
one Saturday evening. For now, it appears that the severe potential
will peak late Saturday afternoon into early Saturday evening. The
main hazard with any severe storms that develop is damaging wind
gusts but could not rule out large hail up to an inch in diameter.

Shower and thunderstorm chances should return Sunday but the severe
threat will be lower due to the lack for forcing behind the front.
Drier conditions are expected much of next week as the
aforementioned upper anticyclone builds over the region.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Dry and VFR for terminals east of the
mountains through the 12Z TAF period. KAVL still has the potential
to see mountain valley fog and/or low stratus develop around
daybreak but the window is quickly closing. Restrictions may return
at KAVL this afternoon/early evening thanks to better chances for
TSRA so introduced a PROB30 from 18Z-22Z. If KAVL does see rain
today, then mountain valley fog and/or low stratus could develop
overnight into daybreak Saturday. Winds at KAVL should remain calm
to light and VRB through most of the TAF period, toggling NW towards
the end of the period. Winds east of the mountains will have a
southerly component through much of the TAF period, but could go
calm to light and VRB at times.

Outlook: Shower and thunderstorm activity should gradually increase
through the holiday weekend as a cold front crosses the area. More
suppressed weather returns by early next week.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NCZ071-072-082.
SC...None.

&&

$$

AR