Area Forecast Discussion
Issued by NWS Greer, SC

Home |  Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
665
FXUS62 KGSP 230018
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
718 PM EST Thu Jan 22 2026

.WHAT HAS CHANGED...
The aviation forecast was updated this evening to reflect the 00Z
TAF issuance.

Periods of light rain still expected tonight and Friday morning.

A Winter Storm Watch remains in effect from Saturday
morning through early Monday afternoon for the entire forecast
area. Upgrades to Warnings will be considered with the next forecast
package. Snow/sleet accumulations continue to slip downward and
ice accumulation amounts continue to go upward.

&&

.KEY MESSAGES...
1. Periods of scattered light precip tonight and Friday morning. A
small potential for very light/low impact wintry weather across
the high elevations. Otherwise, rain is expected.
2. No upgrades to the Winter Storm Watch yet, but the
precipitation types continue to trend more toward ice and away
from snow/sleet. We still expect this to be a major winter storm
across the entire forecast area, leading to hazardous travel and
power outages that may last for days.
3. Dangerously cold wind chills may develop Monday night into
Tuesday morning which could result in hypothermia or frostbite
if precautions are not taken.

&&

.DISCUSSION...
Key message 1: Periods of scattered light precip tonight and Friday
morning. A small potential for very light/low impact wintry weather
across the high elevations. Otherwise, rain is expected.

A very broad baroclinic zone will remain across the forecast area
through Friday morning. This baroclinic zone will steadily intensify
through the night as the height gradient within a broad upper trough
centered over the East strengthens in response to upper low passing
just north of the Great Lakes. A couple of waves move east with weak
isentropic lift and frontogenesis producing periods of showers
across the area tonight and early Friday. Best chance will be along
and south of the I-85 corridor but QPF will be light. Precip that
moves across the NC mountains and I-40 corridor could include brief
periods of a wintry mix; however, no significant accumulations are
expected given the short duration and very light QPF there. Lows
tonight will range from near normal to as much as 10 degrees above
normal. Highs will range from near normal to as much as 5 degrees
below normal.

Dry conditions expected Friday night before the winter storm begins
affecting the area. Lows will be near 5 degrees below normal.


Key message 2: No upgrades to the Winter Storm Watch yet, but the
precipitation types continue to trend more toward ice and away
from snow/sleet. We still expect this to be a major winter storm
across the entire forecast area, leading to hazardous travel and
power outages that may last for days.

All signs continue to point toward a major winter storm across
the region moving in from the west during the day on Saturday,
taking the form of a Miller type `B` configuration. The latest
model guidance continues to drift later on the onset timing by a
bit and the model blend reflects that, so it might not be until
midday before precip begins over the mtns and perhaps mid/late
afternoon over the wrn Piedmont of NC.

The model guidance continues to show two remarkable things. First,
a very cold and very deep boundary layer will take hold across the
region as a large Arctic high over the Great Lakes and upper Midwest
spills down in a cold air damming wedge. The low level air mass is
so cold that it should result in precip to begin as frozen types
across the entire forecast area. Second, the system will be fueled
by a band of Pacific moisture seen on Integrated Vapor Transport
guidance that spreads quickly in from the southwest as the precip
arrives. A brief period of light snow at onset can be expected, but
with a quick transition to sleet as the warm nose comes in. Once
that is established, the sleet may hold on longer than expected
with such a strong warm nose because of the abnormally cold and
deep boundary layer. Most places could get an inch or two of sleet
during this period, before a transition to freezing rain begins.

That being said, the guidance continues to show a more stronger warm
nose developing Saturday night, resulting in a mix then switch
to freezing rain across much of northeast GA/Upstate SC into
NC, eventually changing mostly to ZR in western NC as well. The
stronger warm advection does two things to the fcst, first we end
up with more ice accumulation and less sleet in most places, and
second we are able to warm up above freezing by daybreak Sunday
in the southwest upslope areas of southwest NC where cold air
damming typically is not as strong, so ice amounts trend down
there. The trend in the model blend is to bring the warm air up
from the south Sunday afternoon, but this is treated with much
skepticism. Strong CAD wedges typically do not erode that quickly,
but the warm advection aloft also looks formidable. The freezing
rain may persist longer into Sunday afternoon/eve over northeast
GA and the western Upstate than indicated. In the end, our ice
accumulation looks more like the neighborhood of one half inch in
most places, and 0.75 inch along the Escarpment.

The bottom line continues to look like a mess either way with
high confidence that all locations will get sleet and/or ice
accumulations above our warning criteria. However, we will refrain
from issuing warnings until our offices to the west are ready, which
will allow us to have a better handle on expected types/amounts.

In the mean time, continue preparing for a major winter
storm. Regardless of the individual p-types, the important
thing to note is there will be plenty of wintry precip with this
storm. Wintry precip, whether it`s ice, sleet, or snow are going
to have widespread impacts making for hazardous travel and power
outages that could last for days. Prepare an emergency kit for
your car/home and replenish fuel for your car and other heating
sources such as generators. Remember to keep generator outdoors
and at least 20 ft away from entry points to avoid carbon monoxide
poisoning. Don`t forget about your pets. Keep enough non-perishable
food, water, and medications for at least 3 days. Ensure you have
warm clothing and blankets as wel. Charge your phone and devices
in advance so that you are able to receive alerts.


Key message 3: Dangerously cold wind chills may develop Monday night
into Tuesday morning which could result in hypothermia or frostbite
if precautions are not taken.

In the wake of the winter storm, a large continental sfc high that
builds down over the Deep South will bring very cold temperatures
down across the fcst area Monday night with clear sky and a light NW
wind. Low temps are a little bit tricky in that some of the guidance
might not be taking into account the snow cover (or lack thereof),
possibly making incorrect assumptions about having a fresh snow
cover all the way down across the fcst area that would depress the
sfc temps in the model solutions. As the fcst is constructed right
now, we have low temps in record low territory for Tuesday 27 Jan. I
would not be surprised if this drifted slightly upward. However,
there`s enough of a steady light NW wind that our wind chills easily
get down into Cold Weather Advisory criteria early Tuesday across
the mtns/foothills/areas n/w of I-85. Even the lower Piedmont
would stand an excellent chance. We might even have to consider
an Extreme Cold Warning for Avery County and high elevations of
the nrn mountains. We shall see how the fcst temps drift before
we have to consider any watches for cold.

The air mass modifies relatively quickly early next week, but
will remain well below normal on Tuesday, and still on the order
of ten degrees below normal into the middle of the week. This
won`t allow for any accumulations of sleet and ice to melt very
quickly. Travel impacts are anticipated through Monday over the
mountains where temps don`t rise out of the teens and 20s. East of
the mtns, the high temps have trended a bit warmer, but not above
32F for any great lengths of time. It might take several days to
alleviate all the wintry precip on untreated roads. The extremely
cold temperatures could also have severe impacts on those who lose
power. Make sure you have plenty of blankets and warm clothing to
keep warm. Remember to avoid burning fuels like propane or kerosene
indoors as this increases fire risk and carbon monoxide poisoning.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Still seeing widespread light showers south
of I-85, though not impacting any of the TAF sites currently.
Expect generally VFR conditions to persist overnight, with no more
than VCSH warranted at any of the Upstate sites through the period.
Toward dawn, intermittent MVFR conditions could develop at KCLT
alongside a surge in -RA.  Periods of MVFR will be possible across
the Upstate through much of Friday, with brief IFR even possible
at KAND.  Conditions should improve by evening.  Light and variable
winds overnight will turn decidedly NE Friday morning, continuing
at 4-8kts through Friday evening.

Outlook: A major winter storm is forecast to impact the entire
area beginning Saturday morning and continuing through Sunday.
Significant accumulations of freezing rain/ice and sleet are likely
at all TAF sites. Long term prevailing flight restrictions should
be expected into Monday when the system finally moves east. VFR
expected Tuesday.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Winter Storm Watch from Saturday morning through Monday
     afternoon for GAZ010-017-018-026-028-029.
NC...Winter Storm Watch from Saturday morning through Monday
     afternoon for NCZ033-035>037-048>053-056>059-062>065-
     068>072-082-501>510.
SC...Winter Storm Watch from Saturday morning through Monday
     afternoon for SCZ008>014-019-101>109.

&&

$$

JPT/MPR/PM/RWH