389
FXUS61 KLWX 100900
AFDLWX

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

.SYNOPSIS...
Behind exiting high pressure, a quick moving clipper system
will pass through the Great Lakes today. A secondary cold front
will follow suit on Thursday morning. Another fast moving
frontal system will likely reach the area by midday Saturday. 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 TONIGHT/...
The early morning surface analysis places high pressure across
the southeastern U.S. Locally, prevailing southerly winds are
observed in response to warm advection ahead of a strong frontal
system across the Mid-Mississippi Valley. The mean flow above
the surface is mainly out of the southwest to west which is
steering upstream moisture toward the Eastern Seaboard.
Consequently mid-level clouds are fairly abundant, which
combined with southerly flow, has yielded milder overnight
conditions. Relative to 24 hours ago, 08Z/3 AM temperatures are
around 10 to 15 degrees warmer than the previous night.

The leading edge of warm advection precipitation reaches the
Allegheny Front by the early/mid morning hours. Thermal profiles
are initially marginal which supports a rain/snow mix at the
onset. However, the combination of vigorous lift in the column
combined with westerly cold advection will quickly shift things
over to all snow by around the lunch hour. As this snow falls
along and west of the Alleghenies, a gusty west-southwesterly
wind overspreads the area. Within the 925-850 mb layer, the
guidance shows around 40 to 50 knots of flow which will support
blustery winds over the mountains. the combination of falling
snow with these winds will yield near zero visibility at times.
Blizzard Warnings are in place across western portions of
Pendleton, Grant, and Garrett counties beginning at 10 AM this
morning and continuing through the rest of the day and night.
With Froude numbers averaging around 0.50, the degree of
spillover to the east should be significantly reduced.

Moderate to heavy snow will impact areas along and west of the
Alleghenies throughout much of the day and night. While some
brief lulls are possible, the blustery winds should lead to
significant travel issues given the expected near whiteout
conditions. Snow totals are likely to be in the 4 to 8 inch
range, with locally 8 to 12 inches across the western-facing
slopes above 2,500 foot elevation. Travel across the Allegheny
Front will be hazardous and thus not recommended. Check out
weather.gov/lwx/winter for more information on this winter
storm.

Outside of the Blizzard Warnings, a pair of Winter Weather
Advisories are in place across western Highland and eastern
Garrett counties. These each go into effect at 4 PM this
afternoon and continue through the night. 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. Like areas
inside the Blizzard Warnings, blustery wind gusts of around 35
to 45 mph are possible which will aid in significant reductions
in visibility. For the eastern portions of the Alleghenies, the
low Froude numbers will keep amounts much lower (under an inch).

For the rest of the forecast area, some light passing rain
showers are possible, particularly north of U.S. 50. Total
amounts should be quite meager, generally under 0.05 inches.
Otherwise, temperatures return to near average as highs rise
into the 40s to low 50s (warmest across Shenandoah Valley back
to the Allegheny mountain valleys). This comes with mostly
cloudy skies and brisk southerly wind gusts of 20 to 30 mph.

Heading into the night, the winter storm continues along the
Allegheny Front with blizard conditions likely. The cold front
accompanying the system initially over northern Illinois tracks
across the region by this evening. This shifts winds over to
west-northwesterly into the night with gusts around 15 to 25
mph, locally up to 30 to 40 mph across the higher elevations.
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 where the blizzard
continues.

&&

.SHORT TERM /THURSDAY 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.

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 D.C. 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. Much of the focus
for any snow showers would be from the I-81 and points westward.
However, occasional models do show light snow trying to expand
eastward into the metro regions. Will maintain a 20 to 40
percent chance of snow given this scenario is still plausible.

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 TUESDAY/...
The first half of the day Saturday should be quiet in terms of
precipitation. Dry conditions with a chilly breeze is expected.
As we get into Saturday afternoon and evening, a disturbance
will race southeastward across the Lower Great Lakes and bring
much of the region at least a chance for light snow or light
rain depending on location and surface temperatures later in the
afternoon. Most of the definite snow accumulation would be in
the northern Alleghenies. Temperatures will be about 5 to 10
degrees below average with highs in the middle 30s in the
mountains to the middle 40s near the Bay and eastern Virginia.

An associated surface cold front is expected to push across the
region Saturday night, only to usher in very cold air that will
bring our temperatures back down to where they will be nearly 15
degrees below average. Highs in the lower 20s in the mountains to
middle 30s interior and lower 40s near the Bay. As of now, we can
anticipate dry and breezy conditions with clouds giving way to
sunshine due to downsloping flow. Wind chills late Sunday into
Sunday night could be widespread in the single digits above zero,
except for single digits below zero in the Alleghenies.

Cold and dry conditions should continue Monday and Tuesday with a
strong dome of high pressure building overhead. Temperatures are
expected to only reach the middle 30s both days.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions are expected for all terminals through at least
Thursday, if not longer. A few showers could briefly impact TAF
sites during the late morning to mid afternoon hours. However,
have limited this to a PROB30 group given it is looking less
likely at this time. Otherwise, the main story will be the
periods of gusty winds as a series of clipper-type systems race
from the north-central U.S. toward the Eastern Seaboard. For
today, southerly gusts up to 20 to 25 knots are likely through
the early evening before a cold front sweeps across the region.
Winds shift to west-northwesterly tonight behind this boundary.

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 any impacts to the terminals.

VFR conditions through midday Saturday, then again overnight
Saturday through the day Sunday. Saturday afternoon could have snow
showers moving across the MRB terminal and bring conditions to MVFR
briefly. Winds west 5 to 10 knots Saturday. Winds northwest 10 to
15 knots gusts 20 knots Sunday.

&&

.MARINE...
Hazardous marine conditions are likely with Small Craft
Advisories in place across all waters through early Thursday
evening. Initially, winds over the marine waters will be out of
the south-southwest with gusts in the 20 to 30 knot range. There
are some hints of near gale force winds over the southern waters
this afternoon. However, given southerly regimes can often
underperform in terms of gusts and a similar temperature between
the air and sea, such gusts should be limited and sproadic in
nature. A cold front sweeps through the waters later this
evening with winds shifting to west-northwesterly overnight.

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 the more southern waters.
Gradients weaken into Friday as high pressure briefly builds in.
Gusts of 10 to 15 knots should be the highest observed.

SCA conditions possible Saturday afternoon and again late Saturday
night. SCA likely Sunday and Sunday night. As a matter of fact, cold
air advection and wind could be strong enough over the central and
southern Bay as well as the Lower Tidal Potomac that Gales could
occur later Sunday afternoon and Sunday night.

&&

.TIDES/COASTAL FLOODING...
Current tidal anomalies have spiked into the 0.75 to 1.25 feet
range given the continued southerly winds. Havre de Grace and
Annapolis likely will reach Action stage at least one more time
before the winds shift behind a quick moving clipper-type system
this evening. Water levels fall off rather abruptly in the wake.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 6 PM EST Thursday for MDZ008.
     Blizzard Warning from 10 AM this morning to 10 AM EST Thursday
     for MDZ509.
     Winter Weather Advisory from 4 PM this afternoon to 7 AM EST
     Thursday for MDZ510.
VA...Winter Weather Advisory from 4 PM this afternoon to 7 AM EST
     Thursday for VAZ503.
WV...Blizzard Warning from 10 AM this morning to 10 AM EST Thursday
     for WVZ501-505.
MARINE...Small Craft Advisory until 6 PM EST Thursday for ANZ530>543.

&&

$$

SYNOPSIS...BRO
NEAR TERM...BRO
SHORT TERM...BRO
LONG TERM...KLW
AVIATION...BRO/KLW
MARINE...BRO/KLW
TIDES/COASTAL FLOODING...

NWS LWX Office Area Forecast Discussion