183
FXUS62 KGSP 021041
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
641 AM EDT Tue Sep 2 2025

.SYNOPSIS...
High pressure remains centered along the East Coast through
Wednesday. Conditions will be mostly dry with the exception of
mountain/foothill showers and storms returning on Wednesday. A weak
cold front approaches from the northwest on Thursday and may bring
another round of showers and storms to the area. Temperatures remain
below seasonal normals through Thursday. An upper ridge may build
eastward from Texas over the weekend resulting in a warming trend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 120 AM EDT Tuesday: Another lobe of vorticity will pivot
through a persistent longwave trough axis, crossing the southern
Appalachians today. Mid-level energy and moisture have produce a
fair amount of mid clouds across the TN Valley to the NC mountains,
with some spreading east into the Piedmont. These clouds look to
limit fog potential in the mountain valleys this morning, and will
likely continue to some extent thru daybreak.

Overall, little change in the pattern today, so expect similar
wx conditions to yesterday. Dry NELY low-level flow continues to
keep most of the FA stable, while isolated to widely scattered
showers and a couple of garden-variety tstms develop in the western
NC mountains. With the sfc high weakening along the East Coast,
winds should be lighter than yesterday, and temps will be similar
to yesterday`s readings under partly to mostly sunny skies.

Tonight, another shortwave will dive into the longwave trough axis
and support lingering mid clouds once again across the mountains,
and possibly spreading east at times. The 850 mb flow will turn
out of the SW across the NC mountains overnight. Models are in
decent agreement on potential convection forming in response to
the shortwave across eastern TN and northern GA overnight, with
some showers possible in the NC mountains near the TN border and
in the GA mountains. So a 20-30% PoP will be carried across much
of the mountains. The expected cloud cover will likely limit fog
development in the mountain valleys again. Lows will be 3 to 8
deg below normal east of the mountains, but near normal in the
mountains under the cloud cover and some WAA.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 1137 PM Monday: By Wednesday, a deep closed upper low will be
dropping out of the Canadian Prairies into the Great Lakes
region/southern Ontario. Broad and weak troughing will extend across
the Deep South into the Appalachians with a subtle shortwave
perturbation dropping across the Tennessee Valley and into the
southern Appalachians. Surface high pressure will be sliding
offshore, but a residual wedge of dry air will still reside east of
the mountains. Guidance is in general agreement that the best chance
for showers and thunderstorms will be across the mountains on
Wednesday closer to the weak upper wave and within a better
reservoir of moisture/instability. Some activity may survive into
the adjacent foothills, but coverage east of the mountains should
remain widely scattered at best. By Thursday, the previously
mentioned large closed upper low will be meandering just north of
the Great Lakes with a series of potent shortwave troughs diving
across the Northern Plains and into the Midwest. The lead wave is
progged to be swinging across the Mississippi Valley and lifting
towards the Mid-Atlantic on Thursday. An attendant surface cold
front is also forecast to be draped across the Ohio Valley. The
western Carolinas and northeast Georgia will be on the far southern
periphery of better upper level forcing with the strongest height
falls displaced well north of the area. In fact, H5 height
tendencies are neutral at best. At least some degree of convection
can be expected ahead of the front, but coverage could be rather
limited in the absence of better forcing. Compressional warming
ahead of the front will result in a warming trend by Thursday with
highs back into the low to mid 80s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 1149 PM Monday: The previously mentioned cold front on
Thursday will likely stall northwest of the area as upper forcing
quickly lifts into New England with flow becoming zonal and boundary
parallel. However, the upper trough reloads heading into Friday as a
second potent shortwave trough dives across the Northern Plains. A
large sprawling surface high dropping into the Great Plains will
further help to push the frontal boundary east with the front
dropping into the area Friday into Saturday. Rising heights and
compressional warming ahead of the front will result in a notable
warming trend heading into late week and the weekend with upper 80s
to low 90s common east of the mountains by Saturday. Forcing will
once again be in question with the front itself acting as the main
driver for any showers and storms. Seasonable weather for early
September returns late weekend into early next week in the wake of
the front, although progression of the front is not entirely
certain. Should the front slow and/or stall over the area unsettled
weather could continue into next week.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR conditions expected thru the period,
A mix of mid clouds and a lower-VFR cu field is expected
across the area today, with perhaps some increase in clouds this
evening. Mountain valley fog did form in the usual locations, but
has not quite reached KAVL. With increased clouds expected tonight,
confidence in fog at KAVL is low. Isolated to widely scattered
convection will once again develop in the NC mountains, but should
stay west of KAVL. Winds will be a little weaker than yesterday,
still favoring a NE direction at all sites, except toggling to SE
at KAVL by around midday.

Outlook: At least scattered afternoon/evening convection will
return for much of the area Wed and Thu before diminishing again
late in the week. Nocturnal valley fog and/or low stratus will
also be possible each night and early morning, especially at
mountain terminals.

&&

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

&&

$$

SYNOPSIS...TW
NEAR TERM...ARK
SHORT TERM...TW
LONG TERM...TW
AVIATION...ARK