231
FXUS61 KLWX 081515
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1015 AM EST Mon Dec 8 2025

.SYNOPSIS...
A cold front will push to the south with an upper level low
pressure system passing to the south today. Both of these
systems could bring some light snow to the mountains, the
Virginia Piedmont, and to the I-64 corridor. Brief Canadian high
pressure builds again Tuesday before another area of low
pressure and series of fronts cross the area during the middle
to latter portions of the week. This brings renewed cold air to
the region. High pressure returns by Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Added the northern Blue Ridge zone (mainly south of US 211) and
Greene County to the Winter Weather Advisory based on traffic
cameras. Dry advection has been rapidly eroding the
precipitation shield from the north, but this should level out
near or south of Harrisonburg to Fredericksburg as stronger
forcing and deeper moisture win out. There is still some
consideration for expanding the advisory across Orange and
Spotsylvania Counties (especially the southern sections), but
temperatures started higher than previous forecasts, and
combined with weak solar insolation and early season ground
warmth has been causing a lot of snow to melt outside of higher
rates in banding. Therefore, impacts may be minimal even if snow
continues the rest of the day. Temperatures are not a problem
in the higher elevations, and if model QPF forecasts are
correct, we could easily see some 5 or 6 inch amounts on the
ridges from Highland to Nelson.

Previous discussion:

A shortwave aloft digging across the Tennessee Valley will set
the stages for a winter storm over the Potomac Highlands to the
I-64 corridor. Broad ascent ahead of this impulse should help
spread a light to moderate swath of snowfall across the
mentioned areas. Winter Weather Advisories have been issued for
the Potomac Highlands eastward to the central Virginia Blue
Ridge and into Albemarle County. Running between 5 AM and 5 PM,
a broad 1 to 3 inches of snow is expected, locally a bit higher
across areas of higher terrain. High-resolution models continue
to show some northward expansion of this axis of light snow.
However, it does appear this should focus south of I-66/U.S. 50.

While snow blankets those well south of the metro areas, the
entire region will feel the impacts of cold temperatures and
blustery winds. Observed temperatures early this morning will
not change a whole lot through the day as cold advection wins
out. Highs today should only reach the upper 20s to mid 30s,
with upper teens to mid 20s in the mountains. Behind the front,
winds move from northwest to north-northeasterly with afternoon
gusts to around 20 to 25 mph. This lowers mountain wind chills
into the single digits. Clouds are forecast to dominate through
the day with the elevated winds diminishing after dark. Any
potential for snow across far southern Maryland also drops off
by the early evening hours.

Expansive Canadian high pressure builds in from the Great Lakes
this evening. This 1030-mb anticyclone center settles over the
area tonight yielding a very cold night across the Mid-Atlantic
region. The combination of a dry air mass, light winds, and
clearing skies (away from the Alleghenies) will help usher
widespread low temperatures into the 10 to 18 degree range.
Spotty upper single digits are possible as well as dew points
plummet into the 0 to 10 degree range. For those along and east
I-95, upper teens to low 20s are more likely.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The area will be off to a very cold start on Tuesday morning as
Canadian high pressure remains in place. While Tuesday should be
milder than today, it will likely take until the lunch hour to
break the freezing mark. As high pressure pushes offshore, winds
eventually shift over to southerly by the late morning/early
afternoon. Despite the change in wind direction, temperatures
should not warm appreciably as 1000-500 mb thicknesses only
rise by around 4 to 6 dm (525 dm to 531 dm in a 24-hour
window). Forecast highs push into the mid/upper 30s, with some
low 40s across the Allegheny mountain valleys. For those in the
mountains and near the Mason-Dixon Line, temperatures should
stay closer to freezing. Cloud cover increases through the day
as the mid/upper troposphere begins to moisten.

Expect southerly winds to increase through Tuesday evening and
into the night. Mountain wind gusts may approach 25 to 35 mph
during this southerly surge. Clouds further thicken ahead of the
next weather maker with low temperatures dropping into the mid
20s to around freezing. A light rain/snow mix could reach
western Maryland ahead of daybreak. This is all in response to
the next weather maker.

On Wednesday morning, the upstream system of interest will be
located near Lake Michigan in the form of a sub-985 mb cyclone
center. This quick moving clipper-type system should accelerate
eastward in time while reaching the Eastern Seaboard late
Wednesday. Although forecast highs are able to rise into the mid
40s to low 50s (mid 30s to low 40s for mountain locales), it
does come with the risk of some light precipitation. A rain/snow
mix hits the Alleghenies, while downstream locations can expect
spotty rain showers. Winds remain elevated with brisk southerly
winds continuing. Gusts up to 20 to 30 mph are expected,
locally up to 35 to 40 mph along the Allegheny Mountains.

Behind the cold front, a gusty west-northwesterly wind ensues.
This comes with continued near-advisory caliber winds over the
mountain ridgetops. Low temperatures are forecast to fall into
the mid 20s to low 30s (upper teens to low 20s for the
mountains). The added winds will make it feel more like the
single digits. Additionally, upslope snow showers take shape
along and west of the Alleghenies. A quick inch is possible
during the overnight hours.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Broad upper level trough with numerous reinforcing shortwave-troughs
is expected to dominate the flow across the eastern CONUS during
second half of the week supporting well below normal temperatures
and the threat of accumulating snow showers, mainly across the
higher elevations.

The first cold front should have exited the area by 12Z Thu. There
should be a lull in snow shower activity across the mountains Thu as
cold air advection ceases and low-level curvature becomes
anticyclonic as high pressure builds overhead. A shortwave-trough
passing across PA and western MD may produce some light snow across
the mountains, but it should remain sub-advisory criteria.

A more potent shortwave-trough/closed upper low diving from the
Upper Midwest will help push an Arctic front through the area Fri
night bringing the coldest air so far this season. Strong cyclonic
vorticity advection and strengthening CAA pattern on brisk NW flow
will lead to an enhanced period of moderate to potentially heavy
snow shower activity across the mountains. Ensemble QPF shows 0.2 to
as much as 0.5 inches liquid equivalent and when combined with very
cold temperatures in the teens and single digits (i.e. very high
SLRs) indicate potential for high end advisory or winter storm
criteria event for the mountains. Given the strength of the sfc flow
and very cold temperatures, snow showers are certainly possible east
of the mountains which may result in light accumulations of greater
than a coating. The snow threat ends by Sunday as Arctic high
pressure settles in, but still very cold nonetheless.

&&

.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Restrictions today will focus on KCHO given the ongoing snow.
Precipitation there should taper off by late afternoon with
increasing ceilings. Other than a possible light flurry, the
snow should remain south of IAD and DCA. Otherwise, the big
story today is the winds behind a passing cold front. Northerly
winds should gust to around 20 to 25 knots this afternoon while
switching over to north- northeasterly later in the day. As
Canadian high pressure builds in, winds turn light this evening
into Tuesday morning.

VFR conditions continue for Tuesday and Wednesday. As high
pressure moves off the coast, winds shift to southerly on
Tuesday. These pick up in intensity during the late afternoon to
evening period with gusts to around 15 to 20 knots. Further
upticks in wind are expected for Wednesday ahead of a fast
moving clipper-like system. Gusts up to 20 to 30 knots are
possible before winds shift to westerly late Wednesday behind
this front.

NW winds Thu, light winds Fri, and then strong Arctic frontal
passage Fri night.

&&

.MARINE...
Northerly winds have increased in the wake of a cold front. A
few gusts near gale force have been observed along the
Chesapeake, but this threat appears to be short lived with winds
leveling off by afternoon. Small Craft Advisories are in place
through this evening, extended through tonight for the southern
waters. High pressure over the region leads to lighter winds
into Tuesday morning before southerly channeling ensues as this
high exits the coast. Small Craft Advisories will likely be
required for Tuesday evening and night, while continuing into
all of Wednesday in response to a quick-moving clipper-like
system. Gusts up to 25 to 30 knots are possible this period.

Small Craft Advisories may continue Thu with potentially lighter
winds by Fri.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 6 PM EST this evening for MDZ008.
VA...Winter Weather Advisory until 5 PM EST this afternoon for
     VAZ025-026-036>038-503-504-507-508.
WV...Winter Weather Advisory until 5 PM EST this afternoon for
     WVZ505-506.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ530-
     531-535-536-538-539.
     Small Craft Advisory until 2 AM EST Tuesday for ANZ532-533-
     540>542.
     Small Craft Advisory until 6 AM EST Tuesday for ANZ534-537-543.

&&

$$

SYNOPSIS...BRO
NEAR TERM...ADS/BRO
SHORT TERM...BRO
LONG TERM...LFR
AVIATION...ADS/LFR/BRO
MARINE...ADS/LFR/BRO