Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

810
FXUS61 KLWX 010112
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
812 PM EST Wed Dec 31 2025

.SYNOPSIS...
A reinforcing shot of cold air, wind, and mountain snow look to
accompany an area of low pressure and it`s associated cold front
tonight into tomorrow morning. High pressure briefly returns
from the west Friday before another area of low pressure passes
to the south Saturday into Sunday. High pressure returns briefly
later Sunday with another clipper type system set to push
across the area early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A potent upper-level disturbance and its associated cold front
are moving from the Great Lakes into the Ohio Valley and
Pennsylvania this evening. The upper-level disturbance will pass
by close to our north overnight and the cold front will move
into the area from northwest to southeast overnight.

For locations along and west of the Allegheny Front, Winter
Storm Warnings remain in effect for most areas, with western
Highland and extreme western Allegany Counties both in Winter
Weather Advisories. The combination of the upslope flow, strong
mid-level forcing, and saturation within the DGZ along with
instability and high SLRs (15-17:1 increasing to 20 to 22:1)
suggest that significant accumulation is expected (around 6-
10"+ along and west of the Allegheny Front). Strong winds
gusting to around 40 to 50 mph will also create poor visibility
at times, with near-blizzard conditions possible. Of particular
concern is the timing, with the onset of the worst conditions
likely occurring right around, or just before, midnight on New
Year`s Eve/New Year`s Day. When all is said and done, areas in
the warnings could see anywhere from 6 to 10 inches +, with the
areas in advisories between 2 and 5 inches.

For the rest of the area through the rest of this evening, we
will remain remain on the milder side of the boundary with light
southwest winds and dry conditions east of the Allegheny
Highlands (could be a few flurries or a light snow shower near
the PA/MD line). Temperatures will remain in the 20s across the
mountains to the lower and middle 30s for most other locations.
However, a few spots have dipped into the 20s this evening
across the Virginia Piedmont where mainly clear skies, and light
winds have allowed for radiational cooling. Do think
temperatures may actually rise late this evening/overnight into
the 30s across these areas as clouds return and the flow
increases.

The boundary will move into the area overnight, first across
northern Maryland/eastern WV, and northern VA between 2 AM and 4
AM, then through the metro areas between 4 AM and 6 AM before
clearing central VA/the VA Piedmont and southern Maryland early
Thursday morning. A line of snow showers may accompany the
frontal passage, followed by gusty northwest winds (30 to 45
mph gusts) and falling temperatures. The snow showers may coat
the ground, and with temperatures falling below freezing behind
the boundary, this may result in some slippery spots after 3 AM
into early Thursday morning.

The best chance for a coating of snow and slippery
spots will be across northern MD/eastern WV, and extreme
northern VA. Forcing along the front will be strongest for these
areas and there may be a little instability to work with as
well, causing saturation to approach the DGZ. This combined with
the strong wind surge behind the front may cause a threat for a
brief snow squall. However, confidence is low due to low-level
dry air which may allow for vsbys to remain above 1/4 mile. Will
continue to monitor overnight.

Farther south and east, the surface front is outrunning the
upper-level forcing and there is plenty of low-level dry air.
This decreases confidence for heavier snow showers or a squall,
but still there is a nonzero threat for some slippery spots and
for snow to coat a few surfaces due to a brief snow shower.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Accumulating upslope mountain snow showers will likely linger along
and west of the Alleghenies through Thursday midday. Northwest flow
will gradually diminish as the moisture source is choked off
given brief high pressure building in from the Ohio River
Valley. The high will gradually settle overhead Thursday night
into Friday bringing drier and colder conditions. Winds will
also decrease during this time as the gradient finally relaxes
heading into late week.

Expect highs Thursday in the teens over the mountains with upper 20s
and low 30s, along and north of I-66/US-50. Locations south will be
a touch warmer with highs in the mid 30s. Northwest winds will gusts
20 to 30 mph with (35 to 45 mph gusts mtns.) Thursday morning
into Thursday evening. This will yield single digit to below
zero wind chills over the mountains with teens and 20s for feels
like numbers east. The northwest winds will also bring down
drier air to the surface, so cut Tds tomorrow afternoon to
account for this. Lows Thursday night will fall back into the
teens and 20s under clearing skies and decreasing winds.

High pressure will shift off the southern Delmarva coast Friday
morning into Friday afternoon. Meanwhile, stalled front to the
south will try to lift back to the north Friday afternoon into
early Saturday. This system will lead to extra cloud cover,
mainly south of I-66/US-50 and down around I-64. Any
precipitation chances will remain south of US-460 in VA. The
front flops back to the south Saturday morning. Highs Friday
will range from the upper 20s and low 30s over the mountains to
upper 30s and low to mid 40s east. Lows Friday night will fall
back into the upper teens over the mountains with low to mid 20s
east.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A strong upper level low over eastern Canada will continue to pull
in cooler and drier air into the northern mid-Atlantic region this
weekend. Zonal to a slightly troughy pattern will be in place over
our region with models and ensembles suggesting a southern stream
shortwave will bring precipitation to parts of the Carolinas and
Virginia during the early parts of this weekend. Model guidance over
the past few days have trended slightly northward with precipitation
this weekend, but models continue to keep most precipitation mainly
south of our forecast area. If the northern trend in precipitation
continues, parts of our region could observe some wintry
precipitation especially with a cold air mass in place.

The southern clipper low is forecast to be off-shore by Sunday with
high pressure favored to build over the region through early Monday.
Multiple clipper systems next week may bring additional chances for
precipitation to the region.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
An additional wave of low pressure and reinforcing cold front
look to track across the region late tonight into Thursday
morning. This may bring an additional a brief snow shower in the
08-11z timeframe late tonight. MVFR/IFR vsbys are possible
during this time and snow could coat a few surfaces (especially
around KMRB, but possible anywhere). A surge of northwest winds
behind the front will gust around 35 knots for a few hours late
tonight into early Thursday morning. Winds will diminish some
for late Thursday morning into Thursday afternoon, but gusts
around 20 to 25 knots are still most likely. Winds will continue
to diminish Thursday night.

VFR conditions are expected Thursday through Friday. Light winds
are expected Thursday night through Friday.

Low ceilings will be possible on Saturday, but VFR conditions are
likely to return Sunday. Additional restrictions are possible early
next week.

&&

.MARINE...
An SCA is in effect for the Bay and lower Tidal Potomac River
this evening and for all of the waters overnight. A cold front
will pass through the waters from northwest to southeast between
4 AM and 8 AM late tonight into Thursday morning. A surge of
northwest winds are expected behind the cold front and some
gusts around 35 knots (gale-force) are likely. Did not issue a
Gale Warning since this is most likely to be short fused for a
couple hours or so. Special Marine Warnings may be warranted
during this time.

For the rest of Thursday, an SCA is in effect for all of the
waters for gusty northwest winds around 20 to 30 knots.

High pressure will lead to diminishing winds late Thursday
night into Friday. Sub-SCA level conditions are expected at this
time.

Sub-Small Craft Advisory level winds are favored in the long term at
this time.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 4 PM EST Thursday for MDZ008.
     Winter Weather Advisory until 10 AM EST Thursday for MDZ501.
     Winter Storm Warning until 10 AM EST Thursday for MDZ509-510.
VA...Winter Weather Advisory until 10 AM EST Thursday for VAZ503.
WV...Winter Storm Warning until 10 AM EST Thursday for WVZ501-503-
     505.
MARINE...Small Craft Advisory until 4 PM EST Thursday for ANZ530>534-
     537>543.
     Small Craft Advisory from 2 AM to 4 PM EST Thursday for ANZ535-
     536.

&&

$$

SYNOPSIS...BJL/CPB/EST
NEAR TERM...BJL/CPB/EST
SHORT TERM...CPB/EST
LONG TERM...JMG
AVIATION...BJL/JMG/CPB
MARINE...BJL/JMG/CPB