647
FXUS62 KGSP 111802
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
102 PM EST Thu Dec 11 2025

.SYNOPSIS...
Cool high pressure will control our weather into the weekend.
Another cold front is set to sweep across the area early
Sunday, bringing a very cold and dry airmass for the start of next
week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 1239 PM EST Thursday...

Mostly quiet weather on this fine day as broad 1020mb high pressure
centered over the Gulf coast meanders eastward.  Some degree
of CAA is still underway across the North Carolina mountains,
but gusts are becoming increasingly infrequent per recent surface
obs, and recent satellite/radar imagery indicates NW flow snow in
the Appalachians has largely concluded, but for some continuing
flurries across Mitchell and Avery Counties.

Key Message #1: Quiet weather continues on Thursday and into Friday.

As the axis of a deamplifying z500 shortwave pivots east of the
forecast area early Thursday afternoon, the upper pattern will
flatten out while remaining somewhat constrainted overnight into
early Friday.  In the lower levels, CAA should quickly abate through
mid-afternoon Thursday, allowing winds to slacken considerably. Some
guidance depicts a weak lee trough developing this afternoon,
resulting in a period of S/SW winds before becoming light and
variable overnight into Friday.  For most of the forecast area,
conditions should remain dry through late Friday.  Temperatures are
still expected to peak below climo this afternoon, but should climb
back toward normal on Friday amid weak low-level WAA and a slight
downslope component to daytime winds.

Key Message #2: Snow flurries briefly develop Thursday night over
the northern Blue Ridge and Foothills.

Another area of z500 vorticity is expected to dig out of the
Cumberland Plateau into the northern NC Appalachians early Friday
morning, in conjunction with an 850mb wave lifting out of the
Tennessee Valley and northern Georgia during the day.  In advance
of this feature, guidance depicts at least light snow developing
in the predawn hours across parts of Avery and Mitchell Counties,
as well as some points farther east into the Foothills and northern
Piedmont. Interestingly enough, this takes place during a period
of low-level WAA, and forecast profiles depict a subtle warm
nose developing. However, that "warm nose" appears to stay below
freezing, rendering it moot for the p-type forecast. Rather, expect
any light precip that develops to be snow, and with essentially no
accumulation, even in the mountains.  For much of the NC mountains
and even some portions of the Foothills and Piedmont, occasional
flurries will persist into Friday evening, becoming increasingly
isolated through midnight or so Friday night and abating entirely
thereafter.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 1130 AM Thu:

Key message 1: Still anticipating briefly warmer temperatures
Saturday.

Weak high pressure in place over the coastal Southeast early
Saturday. Though flow at 500 mb will be slightly cyclonic in
advance of trough digging across the Midwest, 850 mb flow turns
WSW to SW and promotes WAA over previous stalled baroclinic zone
south of the CWA. 500 mb heights actually rise slightly. Under
mostly sunny skies, max temps reach the mid to upper 50s across
most lower elevations, with a few SW NC mountain valleys and the
Savannah Valley areas of GA/SC passing 60.

Key message 2: Small precip chances return to the area Saturday
night and early Sunday morning in advance of Arctic front.

The low-level SW flow should induce some moistening below 800 mb
Saturday night over the Piedmont. However, overnight, it looks
more likely that the approach of the trough axis and Arctic front
out of the OH Valley will neutralize thermal advection and keep
the baroclinic zone centered south of the area. NAM and GDPS
are two models that are on the northern side of the envelope,
in this regard. All the models do depict upper divergence east
of the Apps associated with right entrance region of 250mb jet
streak centered over the NE CONUS, and where that divergence rides
near/over the baroclinic zone, they respond with bands of QPF. The
NAM/GDPS thus produce more precip in our CWA than the GFS/ECMWF
do, those models showing the frontogenesis farther south. PoPs
remain no better than 20-30% for the Piedmont owing to the low
confidence in where (if) the precip bands form. Winds will turn
more westerly overnight and begin CAA; similarly to the spread in
the precip positioning, models vary as to when the cooling trend
begins. NAM for one would suggest a nondiurnal trend for parts of
the Piedmont as WAA hangs on longer in its solution and it seems
to pick up on downsloping downwind of the Escarpment also. Saw
fit to base overnight temps on the NBM hourly trends which allows
colder air to reach the mountains before daybreak Sunday morning,
but east of the mountains delays the cooling, allowing the forecast
to reflect precip most likely ending before temps support a change
to anything other than rain in the Piedmont. Shallow moisture does
not lend itself to snow/sleet there anyway.

Based on the above, westerly upslope PoPs do increase Saturday
night and an early morning change to snow is reflected near
the TN border. The moist layer looks short-lived and shallow so
accumulation still is forecast to remain below an inch in that area,
with probably nothing more than flurries after 12z Sunday.

Key message 3: Below-normal temps and gusty winds for Sunday.

Max temp for Sunday along the TN border probably will be at
midnight that morning (i.e. 05z Sun), and very early in the day
otherwise over the mountains, with CAA ongoing. The Piedmont may
warm slightly through late morning or very early afternoon via
downslope, but temps tumble thereafter. Maxes below freezing in
most of the mountain areas and lower to mid 40s for most of the
Piedmont. Widespread wind gusts of 25-35 mph expected across the
mountains thru early Sunday evening with higher elevations likely
peaking 45-50 mph; thus can`t rule out a Wind Advisory, and/or a
Cold Weather Advisory for onset of subzero wind chills in some of
the higher terrain Sunday afternoon, which spread to lower
elevations into evening.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 1245 PM Thursday:

Key message 1: Exceptionally cold Sunday night and Monday, and
temps still well below normal Monday night.

Strong 1030+ mb Arctic high centers just west of the southern Apps
Sunday night; gradient relaxes such that winds weaken during the
evening, mitigating the wind chill threat in lower elevations,
though temps fall enough that if a Cold Wx Advisory is put into
effect late Sunday, it probably will be retained into Monday
morning. Mins look to be the coldest of the season so far for
most or all of the area, in the single digits or low teens over
the mountains and Piedmont I-40 corridor, and mid to upper teens
elsewhere, even in the Lakelands. Despite clear skies, max temps
Monday will be mainly in the 30s to lower 40s throughout the
area. Winds remain light Monday night and still with clear skies
as the high drifts east of the Apps. Though temperatures rebound
10-15 degrees over the mountains, the Piedmont will be almost as
cold. Tue morning mins in the lower 20s for most areas; wind chill
not suggestive of Cold Wx Advisory at that time, though average
temps over the 36-hour cold period are near our criteria for a
Cold Wave.

Key message 2: Moderating temps Tue-Wed with next chance of precip
being Wed night or Thu.

Shortwave ridge riding over the area Tue will allow temps to climb
back to the upper 40s and lower 50s, 1-5 degrees below normal for
most. Quasi-zonal flow across the Southern US allowing temps to
moderate back a little above normal for Wed. Models still vary in
their handling of the nearly cut-off southern-stream shortwave
and in the timing of a northern-stream wave variously shown in
the northern Plains or Great Lakes, with a few guidance members
showing one or both of those features inciting precip in our area
by early Thursday, and responsible for small PoPs at that time,
probably rain.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere: VFR on tap for the 18z TAF period, with a
few straggling gusts still being reported across the Upstate and
Piedmont...but things mostly quieting down as of around 1730z.
Generally dry conditions should persist through the period.
Winds at some locations have already toggled around to the SW,
and more sites across the region should do so in the coming
hours...before going light and variable overnight.  Should see a
bank of altocu pass overhead during the overnight...resulting in BKN
ceilings at FL050-080...before we clear back out for most of Friday.
Could actually see low-VFR to MVFR ceilings develop north of I-40
overnight as a clipper low passes to our north, but this won`t
affect any of the TAF sites; even KHKY looks to remain solidly VFR.
Winds should pick back up out of the S again Friday afternoon.

Outlook: Another clipper system could bring lower clouds and precip
into the area Saturday night into Sunday, along with gusty winds.
Robust, dry high pressure should settle into the area late Sunday
into Monday.

&&

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

&&

$$

SYNOPSIS...JCW/PM
NEAR TERM...MPR
SHORT TERM...JCW
LONG TERM...JCW
AVIATION...MPR