GSP Forecast Discussion
794
FXUS62 KGSP 312356
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
756 PM EDT Mon Aug 31 2026
.WHAT HAS CHANGED...
The aviation forecast was updated to reflect the 00Z TAF issuance.
&&
.KEY MESSAGES...
1. Heat and humidity return this week. Dangerous triple digit
heat index values are expected across much of the low terrain
each afternoon.
2. Dry conditions Tuesday. Thunderstorm chances steadily return
into the weekend.
&&
.DISCUSSION...
Key message 1: Heat and humidity return this week. Dangerous triple
digit heat index values are expected across much of the low terrain
each afternoon.
A broad upper anticyclone centered over the mid MS Valley will
slowly move east through the week becoming centered over the
Southeast by Thursday. This brings a quick increase in heat with
highs in the mid to upper 90s across most locations outside of the
mountains, and lower 90s in the warmer mountain valleys, through
Friday. Dewpoints will be on the increase as well with values in the
upper 60s to lower 70s for most locations outside of the mountains.
Values in the mid to upper 60s in the warmer mountain valleys will
also be common. This is even with some slight mixing during the
afternoons. The result will be heat index values into the triple
digits across most locations outside of the mountains. A Heat
Advisory looks unlikely for Tuesday, but the potential increases
through the week. Even if an advisory isn`t issued, there will be
the potential for heat-related illnesses to occur.
A week cold front looks to cross the area Saturday. This would bring
some relief for the weekend into Monday. Of course, timing is
uncertain, so we`ll keep a hopeful eye on it.
Key message 2: Dry conditions Tuesday. Thunderstorm chances steadily
return into the weekend.
No significant chance of convection Tuesday as the building upper
anticyclone and high LFC values should suppress any deep convection.
Despite the anticyclone, convective potential returns across the
mountains Wednesday through Friday where differential heating will
be enough to overcome the relatively high LFC`s. That said, the
return could be slower if the low level heating is strong enough
to keep a stronger cap in place. Better chances for convection
develop this weekend as the anticyclone weakens and a shortwave
dives into the Mid Atlantic and pushes a front into our area. Enough
dry air may move into the area behind the front to limit convective
chances to the mountains on Monday.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR through the evening at all terminals,
courtesy of high pressure. We still have a bit of convective debris
cloudiness moving overhead, but that should largely dissipate by
mid-evening. Around midnight, our attention will turn to fog/low
stratus formation over the mtn valleys. The guidance hits it hard
and so do we, because it looks like a good setup. Will limit to
LIFR at KAVL for now, with good confidence. As for KHKY, confidence
is lower so they stay MVFR, though once again they could easily
go LIFR or even VLIFR before daybreak. The restrictions should
dissipate quickly around 12Z if they form. Wind will stay light
and variable through Tuesday with a few high based cu developing
during peak heating. East of the mtns, the direction may favor
S to SW if a weak lee trof develops in the afternoon. Meanwhile,
over the mtns, upslope/upvalley flow will be predominate. Can`t
rule out isolated ridgetop convection during peak heating.
Outlook: Scattered mountain convection expected through Friday then
all areas for the weekend. Fog and low stratus will be possible
each morning, especially in the mountain valleys.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
PM/RWH
NWS GSP Office Area Forecast Discussion
