505
FXUS62 KGSP 011052
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
652 AM EDT Wed Oct 1 2025

.SYNOPSIS...
Dry high pressure ridging down from the Northeast States will
control our weather through the end of the week, bringing cooler
than normal temperatures for Thursday and Friday.  As the center
of high pressure moves to offshore from the mid Atlantic states,
temperatures return to near normal for the weekend.  Moisture
increases by Sunday and early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1:25 AM EDT Wednesday: RADAR is currently showing a few
light returns over the I-77 Corridor, but it`s doubtful that any
of this precip is reaching the ground. Regardless, this activity
should fizzle out over the next few hours. Mid-level altocu has
spread over most of our fcst area over the past few hrs, but it`s
expected to gradually sct out from west to east as the morning
progresses. Mountain valley fog will likely develop where there
is sufficient sct this morning. Lows should remain about a cate-
gory above normal.

Otherwise, hurricanes Humberto and Imelda will continue to move
E/NE and away from the East Coast as a broad upper trof draped
across the Canadian Maritimes provides a route for the northern
passage of the tropical cyclones. In their wake, tall upper rid-
ging builds over the MS Valley and then spreads over the Southeast.
At the sfc, robust high pressure will move across the far southern
reaches of Hudson Bay/James Bay and eventually settle over the New
England area by the end of the near-term period early Thursday.
This will send a backdoor cold front thru our area overnight and
into the morning and scour out the plume of deeper moisture over
our area with PWATs falling below an inch, thus bringing an end
to any lingering showers. Cloud cover will also diminish with mostly
sunny skies returning today outside of any sct low-level cumulus and
a few high cirrus. Cooler air will lag behind the boundary with one
more warm day today with highs reaching the upper 70s to low 80s
outside the mtns.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
As of 1205 AM Wednesday: Not all cold air damming wedges are
cool and wet. The rest of the week will be dominated by a wedge
configuration with a parent high that migrates from the St Lawrence
Valley Thursday to the southern New England coast Friday, to a
position off the Mid-Atlantic coast Saturday. The upper pattern
still looks somewhat blocky, but the anticyclone supporting all
this, centered over the Midwest/OH Valley region Thursday, looks
more dominant than previous model runs, while the upper low looks
even weaker to our south. The upshot is very little chance of any
moisture return through at least Saturday, thus a dry wedge that
will hold Thursday and Friday, but might start to weaken Saturday
afternoon. Sky will be mostly sunny so it won`t seem like a typical
wedge, which should allow temps to stay with five degrees of normal
but on the cool side. The air mass modifies into the weekend,
so temps climb back close to normal for Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
As of 1235 AM Wednesday: Naturally, the demise of our dry wedge is
uncertain from Sunday into early next week. For openers, the models
are in disagreement with when or if moisture will begin to return
from the Atlantic starting on Sunday depending on how strong the
sfc ridge remains across VA and the central Appalachians. Enough
ensemble members break the ridge down by Monday to allow for some
moisture return on an easterly flow such that we introduce a chance
of rain mainly over the mtns for Monday and Tuesday. There won`t
really be anything to dislodge the sfc high from its position
off the Mid-Atlantic coast, keeping it close enough to still hold
across our region. That throws much uncertainty into our forecast,
because the blend continues to have near normal temps for Monday
and Tuesday, but in reality if we have light precip and extensive
clouds those two days, we would end up with at best a lingering cool
pool and at worst an evolution to an in-situ cold air damming wedge,
meaning temps could easily be ten degrees under what we have in the
forecast. We shall see. Meanwhile, the upper anticyclone is expected
to retrograde to the srn Plains by Wednesday as a strong nrn stream
wave digs over the Midwest and Northeast. If that happens, a strong
cold front would be pushed toward our region from the northwest,
possibly reaching the Carolinas on Wednesday, though a lot of the
guidance has this front not getting here until Wednesday night or
Thursday. Precip chances/temps end up around climo for Wednesday
for the time being.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and elsewhere: Expect dry, VFR conditions thru the 12z
taf period. The only exception is at KAVL where I have a TEMPO
for IFR cigs for the first couple of hrs this morning. I expected
they would also see some visby restrictions this morning, but that
has yet to materialize and probably won`t this morning. Otherwise,
expect clearing skies thru the day today. Outside the mtns, winds
will pick back up from the NE later this morning with low-end gusts
redeveloping as mixing increases. Gusts should taper off by the
late aftn/early evening with directions becoming more ELY. At KAVL,
winds will remain light and VRB thru the morning and then favor an ELY
to SELY direction for the rest of the day/evening with light speeds.
Winds at KAVL will eventually favor a SLY direction later tonight/
overnight.

Outlook: Dry high pressure is expected to remain over the region
into the weekend. Expect VFR conditions to prevail with the excep-
tion of patchy early morning fog and low stratus in the mountain
valleys each day.

&&

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

&&

$$

SYNOPSIS...PM
NEAR TERM...JPT
SHORT TERM...PM
LONG TERM...PM
AVIATION...JPT