Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

309
FXUS61 KLWX 120141
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
841 PM EST Thu Dec 11 2025

.SYNOPSIS...
An area of low pressure will track into the Canadian Maritimes
this evening. Another fast moving system will cross south of
the region on Friday. A strengthening wave of low pressure may
impact the area Saturday night into Sunday before Arctic high
pressure moves in by early next week. This ridge exits offshore
by mid-week ahead of the next frontal system.

&&

.NEAR TERM /THROUGH FRIDAY/...
Not much to update for the forecast this evening. Clouds are
steadily increasing as low pressure approaches from the west.
Expect conditions to remain precip free through the night. The
latest high res guidance indicate snow will take a bit to start
tomorrow morning given the dry air at the surface. Lows tonight
will settle in the 20s for most (teens in the mountains).

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
A weak disturbance embedded in northwesterly flow aloft will
track toward the area from the Ohio Valley during the day
tomorrow. This system is expected to produce a period of light
snow across portions of the Potomac Highlands, Central
Shenandoah Valley and Central Virginia during the day tomorrow.
Guidance is in relatively good agreement that snow won`t make it
further northeast than a line extending roughly from Moorefield
to Culpeper to Fredericksburg with the system tomorrow,
although a stray flurry or two can`t be ruled out. While there
is a clear focus on southwestern portions of the forecast area,
there are still some discrepancies with respect to how much
precipitation will fall. Some models such as the 3 km NAM and
WRF-NSSL produce as much as a quarter of an inch of QPF across
Highland, Augusta, Nelson, and Albemarle counties. Other
solutions such as the WRF-NSSL produce almost zero
precipitation. For now, we`ve stuck with NBM as a middle ground
forecast for QPF. This QPF forecast yielded 1-3 inches of snow
across Nelson County and Central Virginia Blue Ridge. As a
result those zones have been added to a Winter Weather
Advisory.

There is both boom and bust potential still on the table still
depending on how much QPF is ultimately observed. Model
soundings show very cold profiles aloft, with nearly all of the
lift occurring through the DGZ. If lift is strong enough, this
would produce large dendrites. Model soundings also show almost
no wind in the boundary layer. In a higher QPF scenario, you
would have large dendrites gently falling and then stacking up
with little fracture or compaction, which would be a near ideal
scenario for very high SLRs. On the other hand, if there isn`t
much lift and resultant QPF, you`d likely get much smaller
crystals that won`t stack up as effectively. So higher QPF will
likely beget higher SLRs and vice versa, which has a
multiplicative effect on snow totals. It`s conceivable that in a
low-end scenario little snow (less than an inch) could be
observed from Highland to Nelson Counties. In a high-end
scenario where both QPF and SLRs are higher (likely 20-30:1 SLRs
in that scenario), close to a half foot could occur along the
Central Virginia Blue Ridge. Hopefully 00z guidance will focus
in better on exact QPF amounts, which should result in higher
forecast confidence.

In terms of timing, snow is expected to move into central
Virginia around 6 AM and end by around 6 PM. Temperatures will
be cold, so there could be potential impacts to both the morning
and evening commutes.

Further north, just cloudy conditions are expected tomorrow
across the DC and Baltimore metros. High temperatures are
expected to be in the 30s across the lower elevations, with 20s
in the mountains.

As we move into tomorrow night, a stray flurry or a bit of
freezing fog could be possible anywhere across the forecast
area. The best chance for snow tomorrow night will be in the
Alleghenies within a brief surge of upslope flow. A coating to
an inch of snow appears likely in the Alleghenies.

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.

As the wave amplifies, most models show a jet steak developing
downstream, with an enhanced band of precipitation developing
in the equatorward entrance region of the jet streak. While
there`s still some uncertainty with respect to exactly where
this band winds up, most solutions have this enhanced band of
precipitation developing along the I-95 corridor Saturday
night. This could result in a relative minimum in precipitation
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).

With such a narrow banded feature, there`s still a fair amount
of uncertainty with respect to how much precipitation will
ultimately fall. Precipitation could also potentially start as a
brief period of rain along the I-95 corridor before much colder
air rushes in later during the night behind an Arctic front. For
these reasons, a wide variety of potential solutions exists,
especially along the I-95 corridor. Further west, a high end-
advisory or low-end warning level snowfall appears likely.
Between the Allegheny Front and Blue Ridge lesser QPF amounts
are likely with all precipitation likely falling as snow. Most
solutions show a coating to two inches of snow in this area, but
as much as 4 inches could be possible in a high end scenario in
the Shenadoah Valley. Further east, around the I-95 corridor,
the widest range of potential solutions exists. If most of the
precipitation were to fall as rain, or the band of higher QPF
were to shift northward out of the area, as little as a coating
to an inch of snow could occur. Currently, we have 1-4 inches of
snow forecast as the most likely scenario to the east of the
Blue Ridge. In a high end scenario, as much as 6 inches of snow
could occur under the heaviest part of the band if the
precipitation stays all snow.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Fast moving low pressure and it`s associated Arctic cold frontal
boundary will exit the area Sunday with a strong dome of Canadian
high pressure building in. This will allow for bitterly cold
conditions Sunday afternoon through Monday night. Temperatures look
to rebound as the Arctic high shifts offshore Tuesday into Wednesday
next week.

Any residual snowfall east of the mountains will quickly come to an
end Sunday morning as low pressure shifts north and east. Residual
upslope snow showers will likely linger over the mountains through
Sunday night given predominant west to northwest flow. Meanwhile,
1044-1050 mb Arctic/Canadian high pressure over the upper Midwest
will build eastward. The tightened gradient between the departing
Arctic cold front and building Arctic surface high will lead to
brisk and blustery conditions Sunday afternoon/evening. Wind gusts
of 30-40 mph are possible with locally higher gusts over the
ridges/waters. This will yield to a combination of plummeting
temperatures and wind chills throughout Sunday into Monday as winds
remain elevated. Overall looking at a non-diurnal temperatures
spread Sunday with high temperatures likely occurring close to
midnight and falling into the mid to upper 20s (single digits and
teens mountains) throughout the day. Lows Sunday night will range
from near 0 over the mountains to the mid and upper teens east of
the Blue Ridge/I-95 metros. These values are 5 to 15 degrees above
record territory for this time of year. Wind chill values will drop
into the single digits and low teens east of the mountains Sunday
afternoon with near 0 to subzero values over the mountains. Wind
chills could drop as low as -20 to -30 degrees for a period of time
over the highest elevations above 3000 feet late Sunday night into
Monday morning. Cold weather hazards may need to be evaluated to
encompass this threat pending on how the forecast evolves in the
coming model cycles.

Cold high pressure settles overhead Monday into Monday night
allowing the winds to gradually settle down. Gusts of 15 to 25 mph
can be expected through the afternoon with highs for most struggling
to make freezing. Mountain locations will remain in the mid to upper
teens throughout the day. The added wind will keep wind chills in
the single digits over the mountains with low to mid 20s elsewhere
across the region. Lows Monday night will fall into the mid to upper
teens and low 20s under clear skies.

The cold weather pattern will be replaced with a warmer one Tuesday
into Wednesday. The deep upper level trough that dominated the
weather pattern over the last several days shifts offshore with
ridging building aloft. This will allow for more of a zonal flow
pattern into the region. Warm air advection will ensue at the
surface late Tuesday into Wednesday as a warm front lifts toward the
region. The warm front will be associated with an area of low
pressure across the western Great Lakes which will drag a cold front
toward the region next weekend into early next week. Until then
expect a chances for a few showers Wednesday and Thursday along with
temperatures that look to warm back to normal and above normal
levels. Highs Wednesday look to push back into the mid 40s and low
50s with mid to upper 50s Thursday. Mountain locations will remain a
touch cooler in the low to mid 40s.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
VFR conditions at all terminals through the night as winds
continue to decrease.

Most terminals will remain VFR during the day tomorrow. The
exception will be at CHO, where low ceilings and light snow are
expected. The low ceilings may briefly work their way north to
the other terminals overnight, and a brief period with some
flurries or freezing fog can`t be ruled out. Winds will remain
light during the day tomorrow through tomorrow night.

VFR conditions and southwesterly winds are expected during the
daylight hours on Saturday. Low ceilings and snow will will
likely move in Saturday night, likely leading to restrictions at
the terminals. Winds will turn out of the northwest and pick up
in magnitude late Saturday night as an Arctic front moves
through the area.

Some temporary sub-VFR reductions are expected to linger early
Sunday morning as low pressure departs the region. Any snow
will wrap up within the I-95 corridor early Sunday morning with
VFR conditions returning Sunday afternoon. Wind will be the
bigger issue for aviators with gusts hovering between 20 to 30
kts. This is especially true at terminals near the waters and
ridges as there will be a stout pressure gradient between the
departing front and incoming cold high pressure system. Breezy
conditions continue through Monday afternoon with winds trending
downward Tuesday. VFR conditions are expected both days with
shower chances returning mid next week.

&&

.MARINE...
Winds have decreased over the northern Chesapeake Bay and middle
to upper tidal Potomac River this evening. The SCA has been
dropped for parts of the water, with winds quickly dropping off
during the second half of the night.

Light westerly winds will become light out of the south tomorrow
afternoon. Winds will slowly pick up out of the southwest on
Saturday, but are expected to stay sub-SCA level in magnitude.
An Arctic front will move over the waters late Saturday night.
Winds will shift to northwesterly behind the front, with SCA
conditions likely late in the night.

High end SCA levels are expected over the waters Sunday in the wake
of a strong cold frontal boundary. A period of gale conditions is
likely over portions of the waters late Sunday into Monday as the
pressure gradient tightens. Winds drop below sub-SCA levels Monday
evening into Tuesday. SCA conditions return with a warm front
Wednesday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Winter Storm Watch from Saturday afternoon through Sunday
 afternoon for MDZ509. VA...Winter Weather Advisory from 6 AM
to 6 PM EST Friday for VAZ036-508. WV...Winter Storm Watch from
Saturday afternoon through Sunday afternoon for WVZ501.
MARINE...Small Craft Advisory until 4 AM EST Friday for
ANZ530>534-537- 539>541-543.

&&

$$

SYNOPSIS...KJP
NEAR TERM...KJP/KRR
SHORT TERM...KJP
LONG TERM...EST
AVIATION...KJP/EST/KRR
MARINE...KJP/EST/KRR