772
FXUS62 KGSP 051024
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
624 AM EDT Sat Sep 5 2026

.WHAT HAS CHANGED...
SPC added a severe risk across a good chunk of the GSP forecast area
for Sunday.

&&

.KEY MESSAGES...
1. Hot and humid again today with triple digit heat index
values returning east of the mountains. A Heat Advisory remains
in effect today from 11 AM to 8 PM for the southern zones. Make
sure to stay hydrated and take frequent breaks in the shade or
air conditioning. Cooler and less humid conditions finally return
behind a cold front starting Sunday.
2. A cold front brings the potential for severe storms each
afternoon and evening over the holiday weekend before drier
conditions return for much of next week. Make sure you have
multiple ways to receive warnings, especially if you have outdoor
plans.

&&

.DISCUSSION...
Key message 1: Hot and humid again today with triple digit heat index
values returning east of the mountains. A Heat Advisory remains in
effect today from 11 AM to 8 PM for the southern zones. Make sure to
stay hydrated and take frequent breaks in the shade or air
conditioning. Cooler and less humid conditions finally return behind
a cold front starting Sunday.

No changes to the Heat Advisory this forecast update as the product
appears well placed based on the 00Z CAMs timing of convection ahead
of a strong cold front this afternoon/early evening. The southern
zones are currently expected to see a later arrival time for storms
compared to the northern zones, so thinking is that the southern
zones east of the mountains are more likely to reach Heat Advisory
criteria compared to the northern zones east of the mountains.
However, if the line of storms ends up developing earlier in the
day, this would act to limit some, if not all, of the southern zones
from reaching Heat Advisory criteria (will have to wait and see what
the 06Z CAM trends are later this morning). Regardless, with a
myriad of outdoor plans expected over the holiday weekend, a more
"impacted-based" Heat Advisory appears warranted.

Cooler and less humid conditions finally return behind the front
starting Sunday, with Monday still expected to be the coolest day in
the forecast period. A warming trend can be expected Tuesday through
the at least Thursday as another upper anticyclone builds over the
southern and eastern United States. Luckily, this dome of high
pressure looks less hot and humid overall. Another cold front looks
to bring back slightly cooler temperatures by late week.


Key message 2: A cold front brings the potential for severe storms
each afternoon and evening over the holiday weekend before drier
conditions return for much of next week. Make sure you have multiple
ways to receive warnings, especially if you have outdoor plans.

A strong cold front will approach from the north through this
evening before tracking across the forecast area overnight. 00Z CAMs
show a broken line of storms developing ahead of the frontal
boundary this afternoon and evening, providing much needed relief
from the heat and humidity. SPC pulled the Slight Risk slightly
farther southwest across the GSP forecast area in their Day 1 Severe
Weather Outlook. Thus, most of western North Carolina and the
eastern South Carolina Upstate are now in the Slight Risk. A
Marginal Risk is in place over northeast Georgia, the western South
Carolina Upstate, as well as Graham and Macon counties in western
North Carolina. This appears warranted as 00Z CAMs depict 20-25 kts
of deep layer shear along with 2,000-3,000+ J/kg of MLCAPE in place
ahead of the front this afternoon and evening, which should lead to
strong to severe storm development. The 00Z CAMs are in fairly good
agreement on timing of storms this afternoon and evening but are not
in as much agreement regarding coverage of storms. The 00Z HRRR
looks the most anemic and thinking is that NW downslope drying may
be playing more of a role in this particular CAM. Regardless, any
storms that develop in this environment will be capable of producing
damaging wind gusts and large hail up to an inch in diameter.

The main change for Sunday (at least compared to this time
yesterday) is that the Day 2 SPC Severe Weather Outlook has a good
chunk of the GSP forecast area highlighted in a severe risk. Most of
the GSP forecast area is in a Marginal Risk, with the exception of
the northern NC mountains, northern NC foothills, and northern NC
Piedmont which are not highlighted for a severe risk. The Slight
Risk extends into portions of Greenwood and Abbeville counties in
SC. With the front expected to be south of the area on Sunday, the
severe threat would appear to be lower compared to today. Guidance
has deep layer shear decreasing to 15-20 kts on Sunday and generally
2,000 J/kg or less of MLCAPE. The best instability would appear to
be across the western and southern zones per the NAMNest and RAP.
The main hazard with any severe storms that develop Sunday afternoon
and evening will be damaging wind gusts but isolated hail up to one
inch in diameter cannot be ruled out.

Drier conditions should return for much of next week as an upper
anticylcone builds across the region. Another cold front may bring
rain chances back Friday.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Dry and VFR through the morning hours,
possibly even the early afternoon hours for some terminals, outside
of mountain valley fog and stratus that developed overnight. Fog and
stratus will lift shortly after sunrise. A cold front will bring a
broken line of TSRA and associated restrictions across the terminals
this afternoon into early this evening so maintained PROB30s at KAVL
and KAND as confidence is lower on these terminals seeing storms.
Introduced TEMPOs across the rest of the terminals due to higher
confidence on storm development. Confidence on timing for both
PROB30s and TEMPOs is low as guidance has not been consistent run to
run regarding TSRA activity. Dry and VFR conditions should return by
early or late evening behind the front. Winds be NW at KAVL through
the period. Winds east of the mountains will start out WSW/SW before
toggling more WNW/NW by late morning or early afternoon. VRB winds
can then be expected by mid to late afternoon into the late evening
hours. Overnight, winds east of the mountains will toggle more N/NE.

Outlook: Another round of showers and thunderstorms develops Sunday,
possibly lingering into Monday. Drier conditions return by Monday
night, lingering through mid-week.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ026-028-029.
NC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NCZ071-072-082.
SC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for SCZ009>014-019.

&&

$$

AR