656
FXUS62 KGSP 101808
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
108 PM EST Wed Dec 10 2025

.SYNOPSIS...
A cold front crosses our region from the northwest this evening as
colder air filters into the mountains with snow forecast tonight
along the Tennessee border areas. High pressure returns Thursday and
into the weekend ahead of an arctic cold front which arrives early
Sunday. Dry and cold high pressure will move in briefly for the
start of next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1236 PM EST Wednesday...

Conditions are mostly quiet across the western Carolinas this
afternoon, with low stratus from overnight having entirely scattered
out, leaving only patchy cirrus across the area to start the day.
The latest surface observations depict a low pressure center just
east of Lake Michigan, and attendant cold front extending from
central Indiana southwestward across the Ozark Plateau and into
extreme eastern Arkansas.  There is a clear wind shift at the
leading edge of this boundary, while cold air associated with the
postfrontal air mass remains well behind the boundary itself.

Key Message #1: Breezy conditions develop this afternoon, especially
across the North Carolina mountains.

Over the next 12 hours, a sharpening z500 trough will dig across
the Ohio Valley and into the Mid-Atlantic, steering the cold front
across Tennessee and into Appalachia by early tonight.  Ahead of the
front, operational guidance depicts a stout 45-55kt LLJ slipping
into the NC mountains (already, we`re starting to see gusts tick
up in response), then pivoting eastward into the Piedmont and
northern Upstate during the afternoon. Higher elevations across
the mountains will likely protrude directly into the LLJ layer,
exposing them to advisory-criteria gusts for much of today, and
even into the first part of tonight. For the lower elevations
both in and east of the mountains, we`ll have to rely on
afternoon mixing to get gusts to the surface. For these zones,
we won`t reliably reach advisory criteria, though an occasional
advisory-criteria gust can`t be ruled out.

As a result, a Wind Advisory remains in place for elevations above
3500ft, valid through 10AM Thursday.

Key Message #2: Near-normal temperatures today cool to below
normal tonight.

The LLJ itself will be embedded within a broader WAA regime
preceding the cold front.  So, for most of today, we`ll see
S/SW flow in the low-levels, which will result in near-normal
highs this afternoon in the mid-50s...or even a degree or two
above normal for some locations in the Savannah River Valley and
southern Upstate.  The onset of aggressive postfrontal CAA tonight
will rapidly lower temperatures, with most of the mountains falling
quickly into the 30s after sunset, and the entire forecast area
seeing lows at least a category below normal Thursday morning.
Those below-normal temperatures will stay in place into Thursday,
with highs only climbing into the upper 40s across the low terrain -
some 2 or more categories cooler than normal!

Key Message #3: Wintry precip develops across the North Carolina
mountains tonight, producing accumulating snowfall at higher
elevations.

Deep moisture pumped into the area by the LLJ will result in an
increase in rainfall across the mountains by mid-afternoon. Forecast
soundings depict a lack of good moisture content in the ice growth
zone initially, with moisture quickly filling in by late afternoon.
Which is to say that almost as soon as temperatures can cool enough
this evening (see key message #2 above), locations across the
mountains should change over from rain to snow...with virtually
all of Appalachia expected to see at least flurries by midnight.
While lower elevations may see no accumulation, or only a dusting,
higher elevations could see 2-3" through Thursday morning, and
isolated locations across the northern Blue Ridge could see totals
in excess of 4".

Therefore, a Winter Weather Advisory will begin at 1 PM today for
elevations above 3500ft.  It will continue through 10AM Thursday,
expiring alongside the Wind Advisory.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 1236 PM EST Wednesday...

Key Message #1: Most locations remain dry outside of a passing
clipper system over the northern mountains on Friday.

Weak cyclonic flow aloft will be in place during the short-term
period, with a passing shortwave to the north on Friday. Guidance
gradually shifting south and clipping the northern mountains
with light rain/snow and little to no accumulations expected at
this time. Otherwise, the airmass is expected to modify with high
pressure moving in with highs at or slightly below normal. Overnight
lows will be a few ticks below normal for both Thursday and Friday.

Key Message #2: Above normal temperatures on Saturday

Rising heights and compressional warming ahead of a strong cold
front will allow for temperatures to rise a few ticks above normal
for Saturday. Model guidance vary on the overall arrival of the
front, but the consensus is that the front should remain just
northwest of the CWFA by 00Z Sunday, allowing for only increasing
high clouds by the very end of the forecast period.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 105 PM EST Wednesday...

Key Message #1: Model guidance continue to trend toward a dry
frontal passage Saturday night into Sunday, cold and breezy behind
the front.

Strong cold front will be in the midst of moving across the CWFA
Saturday night as a digging closed upper low moves across the Great
Lakes region. The better forcing for ascent and available moisture
will be allocated closer to the core of the low and along the Gulf
Coast, leading to a dry fropa. Most of the guidance indicates that
the full fropa should occur by 12Z Sunday with low-level CAA rushing
in behind the front across the mountains, but expecting the typical
downslope delay outside of the mountains during the daytime period
Sunday. A strong continental surface high (~1040mb) will be in the
midst of sliding across the central CONUS with a brief window of
opportunity for northwest flow snow along the immediate TN border
before dry air entrainment shrivels the shallow low-level moisture
layer. Very tight pressure gradient will develop over the mountains
behind the front and suggests that near Advisory criteria gusts
develop over the high terrain starting Sunday morning and linger
throughout the day before gradually subsiding overnight Sunday as
the center of the surface enters the central/southern Appalachians
by Monday morning. Overnight lows on Saturday night should run a
few ticks above normal with weak WAA ahead of the front. Afternoon
highs will run 15-20 degrees below normal across the mountains,
while locations outside the mountains only run 5-10 degrees below
normal thanks to the aforementioned delay to the CAA onset. However,
CAA will be in full affect across the CWFA Sunday night with a
nice shot of Arctic air, leading to overnight lows running 15-20
degrees below normal, with single digits in the highest elevations,
teens elsewhere in the mountains, teens and twenties outside of
the mountains. Wouldn`t be surprised if a Cold Weather Advisory
needs to be issued for the northern mountains when factoring the
lingering gusts with the very cold airmass in place.

Key Message #2: Cold on Monday with a modifying airmass by Tuesday
and Wednesday

Monday will be the coldest day of the seven day forecast period
as the arctic airmass settles in fully with the continental high
centered over the area, leading to afternoon highs running 10-15
degrees below normal. The best radiational cooling conditions are
expected to be Monday night as values continue to run 10-15 degrees
below normal. However, the airmass should modify rather quickly
as a shortwave ridge builds in on Tuesday following the departing
shortwave trough as the surface high drifts offshore. With warmer
thicknesses moving in across the region expect afternoon highs
to warm, but hover at or a few ticks below normal Tuesday and
Wednesday. A southern stream system looks to try and get its act
together by the middle part of next week, but guidance differ this
far out on the overall synoptic outlook and timing on everything.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: VFR everywhere this afternoon, as high
cirrus thickens ahead of an advancing disturbance to our west.
Biggest story for the afternoon is the wind forecast, with at
least sporadic gusts of 30-35kts expected across the terminal
forecast area.  This is driven by a strong LLJ crossing the region,
and so it`ll also result in a period of LLWS for all the TAF sites.
This will mostly peak during the mid- to late-afternoon, and subside
after sunset.  Overnight, skies will mostly return to FEW/SKC
and winds will slowly taper off to a steady 5-10kt NW breeze.
The exception will be KAVL and nearby mountain terminals, which
will likely see at least FEW/SCT low clouds most of the night,
alongside scattered rain showers, becoming scattered snow showers
after midnight.  For now, probability was too low for a mention
of SN at KAVL, but it may need to be added in the next issuance.
VFR continues after daybreak.

Outlook: Expect mostly dry/VFR conditions across the area thru
the weekend.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until 10 AM EST Thursday for NCZ033-048>053-058-
     059-062>064.
     Winter Weather Advisory until 10 AM EST Thursday for NCZ033-
     048>050.
SC...None.

&&

$$

SYNOPSIS...DEO
NEAR TERM...MPR
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...MPR