687
FXUS61 KLWX 101400
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
900 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 leading edge of warm advection precipitation is reaching
the Allegheny Front as of mid morning. 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. Winds are already gusty with
40-45 knot peak gusts above 2500 feet elevation over the ridges
of the Alleghenies. 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 through tonight. With Froude
numbers averaging around 0.50, the degree of spillover to the
east should be significantly reduced except for a relatively
brief period late this afternoon as the front crosses.

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 7 inch
range, with locally 8 to 12 inches across the western-facing
slopes above 2,500 foot elevation along and west of the
Allegheny Front. Travel across this area 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 should keep amounts much lower (under an
inch, except perhaps in localized squalls this evening).

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 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 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. At least several
inches of snow is becoming increasingly likely along and west of
the Allegheny Front, with a chance of some light snow and rapidly
falling temperatures east of the mountains heading into the
Friday evening commute. If precip arrives earlier, the morning
commute could be impacted, as well, but certainty is low.

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 are 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 perhaps
light rain depending on location and surface temperatures later
in the afternoon). The highest confidence for snow accumulation
would be in the northern Alleghenies, but a threat exists
further east as low pressure attempts to develop along the coast,
as well. 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 Chesapeake 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 are expected to be in the lower
20s in the mountains to middle 30s over the interior and lower
40s near the Chesapeake 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 to around zero, with 10
to 20 degrees below zero in the Alleghenies. Cold weather headlines
may be necessary.

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 /12Z 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. 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 impacts to the terminals.

VFR conditions through midday Saturday, then again Sunday.
Saturday afternoon/night could have snow showers moving across,
and could bring at least brief restrictions. Winds will be west
5 to 10 knots Saturday, then northwest 10 to 15 knots with gusts
to 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 water, 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 are possible Saturday afternoon and again late
Saturday night. SCAs are likely Sunday and Sunday night. As a
matter of fact, cold air advection and wind could be strong
enough that Gales could occur Sunday afternoon and 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...Blizzard Warning until 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 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
SHORT TERM...BRO/DHOF
LONG TERM...KLW
AVIATION...BRO/KLW/DHOF
MARINE...BRO/KLW/DHOF
TIDES/COASTAL FLOODING...LWX