695
FXUS61 KLWX 110221
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
921 PM EST Wed Dec 10 2025

.SYNOPSIS...
Behind exiting high pressure, a quick moving clipper system
will pass through the Great Lakes. A secondary cold front will
follow suit on Thursday morning. Another fast moving frontal
system will likely reach the area by midday Friday. A wave of
low pressure may impact the area Saturday night into Sunday
before Arctic high pressure moves in by early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
The leading edge of the cold front is moving through the area
this evening. A few showers have developed along the front, with
one producing a very isolated 40kt gust at the Martinsburg
Airport (KMRB). Radar velocities from KIAD and KBWI indicate any
gusts should be around 30kt or less, with showers weakening as
they move further east. For the Alleghenies, a steadier stream
of heavy snow showers is finally reaching that area, with more
coming upstream from western PA.

Snow has mostly been limited to above 3500 feet since this
afternoon, but now levels will start to quickly lower as strong
CAA reaches the area. Bursts of snow are expected for the next
several hours near and west of US-220 from Cumberland MD to
Monterey VA. The Blizzard Warning remains in effect through
Thursday morning. However, due to the late onset of snow it is
possible these warnings are cancelled at some point tonight.
Still, periods of moderate to heavy snow will impact areas
along and west of the Alleghenies throughout much of the night,
so will be hesitant to cancel anything too early.

Winter Weather Advisories remain for western Highland and
eastern Garrett Counties. Storm totals of around 2 to 3 inches
are expected, locally to around 5 inches across the western-
facing slopes above 2,500 foot elevation. Blustery wind gusts of
around 35 to 45 mph are expected at times, and will aid in
significant (though more intermittent) reductions in visibility.
For the eastern portions of the Alleghenies, the low Froude
numbers should keep amounts much lower (under an inch, except
perhaps in localized squalls this evening).

Check out weather.gov/lwx/winter for more information on this
winter storm.

Elsewhere, winds shift over to west-northwesterly into the
night with gusts around 15 to 25 mph. Skies clear out east of
the Alleghenies as cold, dry advection ensues. Overnight lows
are forecast to fall into the mid 20s to low 30s, with teens
over the Alleghenies.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
The strong shortwave driving this system begins to exit off the
Delmarva Peninsula early Thursday. At the same time, an upper
low tracks southeastward from Ontario toward New England. The
net result of this pattern aloft yields a sub-504 dm mid-level
low centered over upstate New York on Thursday afternoon.
Relative to early/mid-December climatology, these low heights
are around 2 standard deviations below average. The shot of cold
advection picks up on Thursday as 850-mb temperatures fall into
the -12 to -15C range. Thermodynamic profiles are likely to be
dry adiabatic down to the surface which at least raises highs
into the 30s. For those in the mountains, upper teens to 20s
should be commonplace. West-northwesterlies remain gusty which
ushers daytime wind chills into the 20s (single digits down to
around -5F across the Alleghenies). Additionally, this comes
with continued snow showers with Blizzard Warnings in effect
until 10 AM Thursday. While snow tapers off through the day,
blowing snow will likely remain an issue. Additional flurries or
an isolated snow shower or two may linger in modest upslope flow.

Elevated wind fields decrease into Thursday night as a weak area
of high pressure builds in from the Tennessee Valley. Forecast
lows drop into the upper teens to mid 20s, with upper 20s around
the DC and Baltimore urban corridors.

Below average temperatures continue into Friday as highs largely
do not escape the 30s, with 20s in the mountains. As the large
cyclonic circulation aloft shifts focus toward the Canadian
Maritimes, a progressive northwesterly flow aloft sets up over
the north-central to northeastern U.S. An embedded clipper-type
system pushes through the region on Friday. At least several
inches of snow is becoming increasingly likely along and west of
the Allegheny Front, especially south of US-33. There is a
chance of some light snow and rapidly falling temperatures east
of the mountains for the evening commute. If precip arrives
earlier, the morning commute could be impacted, as well, but
certainty is low. Spread in guidance remains large, but trends
in the ECMWF-AIFS have been consistently further south and drier
over the last 2 days. Even so, deep lift through the DGZ could
result in a rather broad area of light snow at times.

Some snow showers linger into Friday night, especially along the
Alleghenies where upslope flow continues. Underneath mostly
cloudy skies, low temperatures will fall into the 20s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A weak ridge of high pressure will become centered over the region
on Saturday. Mostly cloudy skies and dry conditions are expected,
with highs in the upper 30s to mid 40s for most (20s mountains).
Meanwhile, much further to the west, the waveguide across North
America will start to amplify as a system tracks toward the British
Columbia coast. A ridge building event will ensue downstream over
western Canada, which will cause a pre-existing upper low over
the Upper Great Lakes to drop southeastward toward the Mid-
Atlantic and amplify into a shorter wavelength open wave. As
this occurs, large scale forcing for ascent will increase across
the area Saturday night. Precipitation could start as early as
the evening in the Alleghenies, before spreading eastward during
the overnight hours. Most solutions favor precipitation falling
as all snow, although some brief mixing with rain could occur
along/east of I-95 depending on the ultimate track of the
system.

As the wave amplifies, most models show a jet steak developing
downstream, with an enhanced band of snowfall developing in the
equatorward entrance region of the jet streak. While there`s
still some uncertainty with respect to exactly where this winds
up, some of the 12z models have this enhanced band of snow
developing in place along the I-95 corridor Saturday night. This
could result in a relative minimum in snowfall totals between
the Blue Ridge and the Alleghenies, with higher totals along the
I-95 corridor (where the best synoptic forcing will be) and in
the Alleghenies (where there will be some additional upslope
snow as the system departs). There`s still plenty of time for
things to change, and confidence in the forecast details remains
low this far out.

Any snow to the east of the mountains should come to an end by
around mid-morning Sunday, but upslope snow showers may continue
on and off in the Alleghenies through the day Sunday into Sunday
night. Low pressure will deepen as it departs to the east during
the day Sunday as a very strong (1040+ hPa) area of high
pressure builds southward across the Midwest. Gusty northwest
winds will usher the coldest airmass of the season into the
area, with temperatures likely dropping through the 20s during
the daylight hours on Sunday. Temperatures will drop back into
the single digits and teens Sunday night as strong northwesterly
winds continue. Wind chills will likely drop back into the
single digits above/below zero across much of the area, with
double digits below zero possible across the highest elevations.

High pressure will build overhead for Monday and Tuesday,
leading to dry but cold conditions. Highs on Monday will
generally be in the upper 20s and lower 30s, with upper 30s/low
40s on Tuesday.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR conditions are expected to prevail at all terminals through
at least Thursday. Periods of gusty winds will begin tonight as
a series of clipper-type systems race from the north-central
U.S. toward the Eastern Seaboard. A cold front sweeps across
the region tonight, causing winds to become west-northwest between
03Z-06Z. Gusts of 25-30 knots are likely.

Blustery winds are expected on Thursday as gusts push into the
25 to 30 knot range during the afternoon hours. These elevated
winds may last into portions of the evening before decreasing
overnight. Another clpper-type system tracks toward the area on
Friday. Some threat for light snow exists, but confidence is low
on coverage and impacts to the terminals.

VFR conditions are expected during the daylight hours on Saturday.
Sub-VFR conditions appear likely late Saturday night into
Sunday morning in association with snow and low ceilings. Winds
will be out of the west on Saturday, and then gusty out of the
northwest on Sunday.

&&

.MARINE...
Hazardous marine conditions are likely with Small Craft
Advisories in place across all waters through early Thursday
evening.

Winds this evening have decreased a bit from earlier, though
sporadic gusts in the middle 20kt range are being observed. A
cold front will move across the waters through midnight, then
winds shift to west-northwest overnight. Expect gusts between 25
to 30 knots at most locations.

A gusty pattern continues into much of Thursday which supports
the ongoing Small Craft Advisories. These may need to be
extended into Thursday night for portions of the waters.
Gradients weaken into Friday as high pressure briefly builds in;
gusts of 10 to 15 knots should be the highest observed.

Sub-SCA level westerly winds are expected during the day Saturday.
Winds will shift to out of the northwest and increase in strength on
Sunday behind an Arctic front. At least high-end Small Craft
Advisories appear likely on Sunday, and Gale conditions may be
possible.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Blizzard Warning until 10 AM EST Thursday for MDZ509.
     Winter Weather Advisory until 7 AM EST Thursday for MDZ510.
VA...Winter Weather Advisory until 7 AM EST Thursday for VAZ503.
WV...Blizzard Warning until 10 AM EST Thursday for WVZ501-505.
MARINE...Small Craft Advisory until 6 PM EST Thursday for ANZ530>543.

&&

$$

SYNOPSIS...BRO/DHOF
NEAR TERM...BRO/DHOF/KRR
SHORT TERM...BRO/DHOF
LONG TERM...KJP
AVIATION...BRO/DHOF/KJP/KRR
MARINE...BRO/DHOF/KJP/KRR

NWS LWX Office Area Forecast Discussion