636
FXUS62 KGSP 011100
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
700 AM EDT Thu Oct 1 2026

.WHAT HAS CHANGED...
Updated the aviation discussion for the 12z TAF issuance.

&&

.KEY MESSAGES...
1. Temperatures remain well above normal with dry conditions
expected for most locations through Friday, outside of the
potential for a few showers and thunderstorms Friday afternoon
and evening, mainly in the mountains.
2. Cold air damming will set up over the area, bringing cooler
temperatures and widespread rain chances over the weekend,
especially Saturday night into Sunday. Locally heavy rainfall
is possible.
3. Drier early next week with a brief warm up expected Monday
before below normal temperatures return by Tuesday.

&&

.DISCUSSION...
Key message 1: Temperatures remain well above normal with dry conditions
expected for most locations through Friday, outside of the potential
for a few showers and thunderstorms Friday afternoon and evening,
mainly in the mountains.

Upper ridge continues to build over the Southeast today, then
begins to flatten, as a northern stream trough forms across Great
Lakes. Sfc high pressure will remain centered east of the Outer
Banks, with anticyclonic flow over the Carolinas, keeping deeper
moisture at bay. Temperatures will be around 8-12 deg above normal
thru Friday. Friday is expected to be the warmest day of the week,
with highs well into the 80s in the lower elevations, and around
90s in portions of the Lakelands and southeast of Charlotte.

Moisture advection starts to ramp up Friday ahead of a cold front
pushing into the Ohio Valley. Steepening lapse rates and increasing
low-level moisture will result in a few hundred J/kg of sbCAPE
across the western mountains, thus a return of scattered showers
and perhaps, an isolated thunderstorm or two will be possible.


Key message 2: Cold air damming will set up over the area, bringing
cooler temperatures and widespread rain chances over the weekend,
especially Saturday night into Sunday. Locally heavy rainfall is
possible.

The latest models have come into better agreement on a cold front
slipping into the area during the day Saturday. This timing will
make the max temp forecast a bit tricky, as increasing low clouds,
NE wind and showers will lead to cooler temps in the north, but
depending on how far the front can get by late aftn, the southern
areas may still see another warm day. Overall, the trend has been
for a slightly earlier arrival, and thus, max temps have been
trending cooler.

Hybrid cold-air damming should be well in place by Saturday night,
with a mid-level trough providing support for more widespread rain,
while sfc high pressure builds into the Northeast states. PWATs
will be high atop the CAD wedge, but low-level flow remains weak,
and guidance continues to lack much signal for anything more than
localized heavy rainfall. With that said, most areas should get a
nice beneficial soaking rainfall, with precip lasting thru the day
Sunday. With solid CAD in place, most of the area will likely be too
stable for thunder, except for the southwestern NC mountains, like
Smokies and Balsams, which will be on the edge of the wedge. This
doesn`t necessarily mean heavy rain rates won`t be possible, as
the high PWATs and deep warm cloud layer on forecast soundings
suggest even showers could be efficient rain producers. There may
also be elevated CAPE above the wedge to support some thunderstorm
chances. With the CAD, highs should be about 5-10 deg below normal.

Precip is expected to start tapering off overnight Sunday night.
The 18z GFS has finally come in line with the ECMWF and Canadian
on pushing the front south of the area and dry air filtering in
from the north, cutting off PoPs for Monday. The NBM continues to
lag this trend, and has chance PoPs across the southern half of
the CWFA. These PoPs are most likely overdone, given the expected
progressive flow pattern.


Key message 3: Drier early next week with a brief warm up expected
Monday before below normal temperatures return by Tuesday.

An upper trough will dig and shift to the East Coast Monday,
establishing a longwave trough over the eastern CONUS thru most of
next week. This will allow a nice fall air mass to settle over the
Great Lakes to the Mid-Atlantic, with dry conditions and seasonably
cool conditions nosing south into the forecast area. After a mild
day with near- normal temps Monday, highs will be mainly in the 60s
to lower 70s Tuesday and Wednesday (a few degrees below normal),
with lows in the 40s and even into the 30s in the highest elevations
Tuesday night.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Expect dry, VFR conditions to continue thru
the 12z TAF period. The only exception is some sct to bkn MVFR level
stratocu that has drifted over the Upstate terminals over the past
couple of hrs this morning. I included a TEMPO for MVFR cigs at KGSP,
KGMU, and KAND from 12 to 14z, but these cigs could sct before 14z.
In addition, KAVL has yet to see any restrictions this morning and
at this point, it`s looking like they probably won`t. Otherwise, I
expect a few fair-weather cumulus and high cirrus today. Winds should
remain light and VRB to calm thru the morning and then pick up out of
the S/SW this afternoon. They will go light and VRB again later this
evening and pick up again from the SW tomorrow afternoon.

Outlook: Dry and VFR thru at least Friday morning, outside of the
potential for mtn valley fog/low stratus Friday morning. Moisture
will begin to increase across the area Friday aftn/early evening,
mainly across the mtns. More widespread showers and associated
restrictions develop ahead of a cold front this weekend.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

ARK/JPT