Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

938
FXUS61 KLWX 210846
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
346 AM EST Sun Dec 21 2025

.SYNOPSIS...
A weak cold front will cross this morning, followed by a
transient area of high pressure on Monday. A low pressure system
moving through the Great Lakes may affect the area late Monday
night into Tuesday. Another transient area of high pressure on
Wednesday may give way to a warm front on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Low pressure is located over Quebec this morning. A dual front
structure trails to the south and southwest. The first boundary
is crossing the Appalachians and will move eastward through
sunrise, shifting winds to the west. The second boundary will
have a more notable push of cold and dry advection, crossing
during the morning to early afternoon hours. No precipitation is
expected, but bands of mid and high level clouds will result in
mostly cloudy skies at times. Winds will pick up appreciably
with the second boundary, with gusts of 20-30 mph through the
afternoon (30-40 mph possible in the mountains). Initially,
mixing and downsloping will result in mild temperatures, with
50s near and south of I-66. However, highs may be reached by
midday, with steady or slightly falling temperatures during the
afternoon. Rises will be more muted to the northwest, and the
Alleghenies likely hold steady below freezing all day.

Winds will quickly drop off tonight as surface high pressure
builds in from the west. Skies should remain mostly clear, so
there will be plenty of room for temperatures to drop toward
low dew points for locations which can become calm. Widespread
lows in the 20s are expected, with teens in the colder valleys
and outlying areas.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The progressive upper level pattern means the surface high will
quickly traverse the area Monday. Some mid and high level clouds
are expected due to a jet streak aloft. Temperatures will remain
near to slightly below normal, with most locations having highs
in the 40s.

A flatter shortwave trough and relatively weak wave of low pressure
will move toward the Great Lakes Monday night. There is some
potential for an area of light warm advection precipitation to
spread into the area, especially during the second half of the
night. Overall the 00Z guidance tonight is slightly drier
compared to 24 hours ago. Precipitation formation will be
threading the needle for locations east of the Alleghenies, as
it will initially be very dry in the low levels, and then as the
low levels finally saturate, the mid levels begin to dry out.
Temperature guidance has trended a couple degrees warmer as well
(which could make all the difference), but some locations may
drop below freezing during the evening depending on how quickly
cloud cover increases and how much southerly flow is realized
at the surface. On top of that, thermal profiles aloft are also
uncertain, although generally warming with time. Thus there
could be some potential for freezing rain anywhere low-level
cold air remains trapped. Should any snow occur on the front
end, the most probable place for that to occur would be mainly
north and east of Washington DC. With all that said, many areas
may just see rain/sprinkles should precipitation occur at all.
The best moisture and lift will depart by midday Tuesday, with
the trailing cold front set to come through during the afternoon
and evening. Some light upslope precipitation may continue
along the Alleghenies, but even there, it will be warm enough
for just rain. Temperatures may be a little tricky depending on
the progression of the warm sector and any low clouds, and there
could be a gradient from mid 40s to near 60 degrees across the
forecast area. Gusty postfrontal winds could approach wind
advisory criteria along the Allegheny Front Tuesday afternoon
and evening, but it appears much less wind will reach the lower
elevations.

High pressure will build in from the west Tuesday night.
However, with a light northwest wind remaining in place and
minimal cold advection behind the front, lows will be milder,
ranging from the mid 30s to lower 40s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
It`s another year of green instead of white when it comes to the
Christmas holiday. Temperatures look to run 10-20 degrees above
normal through the holiday period with a slight cooldown into the
upcoming holiday weekend ahead.

A broad 500 mb ridge axis will gradually slide east from the
south- central U.S into the Gulf heading into midweek.
Meanwhile, several pieces of shortwave energy will ride the
periphery of the ridge from the northern Plains/upper Midwest
into the Great Lakes region through the end of the holiday
workweek. Each of these pieces of energy have the chance to
bring some rain to region (especially areas west of the Blue
Ridge). Overall forcing will remain to the north and west as
each system looks to track across the Great Lakes. As a result,
we get the associated warm and cold frontal boundaries passing
through during the Christmas Eve/Christmas Day timeframe as well
as the weekend ahead.

The greatest rain chances at least coverage wise appear to be late
Christmas Eve into Christmas Day. This is associated with a warm
frontal boundary that will lift through the region. It won`t be a
total washout with the GFS/GEFS remaining the aggressor when it
comes to the coverage of rain compared to the ECMWF, GDPS, and
ECS counterparts. With that said, looking at 30-50 percent PoPS
for most of the region with 60-80 percent PoPs over the
mountains for the Christmas holiday. This aligns with current
NBM probabilities of 60- 90 percent for a quarter of an inch of
rain over the Alleghenies with 30-50 percent probs of a tenth of
an inch or less east of the Alleghenies and into the I-95
metros over a 72 hour period.

Christmas Eve will feature a mix of sun and clouds with highs
ranging from the mid 40s over the Alleghenies/north-central MD to
mid 50s over the Shenandoah Valley. Lows Christmas Eve night will
fall into the low to mid 30s with increasing clouds and passing
showers as the warm front lifts in. Cloudy skies and passing showers
continue Christmas Day as the warm front works through. Temperatures
will range from the mid 40s and low 50s over the Alleghenies/north-
central MD to low 60s over the central VA Piedmont. Some sun may be
noted later in the day, especially south of I-66/US-50 due to the
proximity of the warm front well north of the region.

Further warming is expected Friday as southerly flow increases. A
bit more sunshine may also be noted (mainly east of the
Alleghenies/Blue Ridge) given the warm frontal boundary
remaining north of the region and lagging cold front over the
Ohio River Valley/Great Lakes. Highs Friday will range from the
mid 50s over the Alleghenies/northeast MD to mid 60s over
northern/central VA.

The northern jet stream will remain fairly amplified heading
into the weekend and early next week as another clipper type
system works across the Great Lakes. The associated cold front
with this clipper system will cross the area Sunday into Monday
bringing additional showers and a return to near normal temps.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
VFR conditions are expected through the TAF period. Any threat
of LLWS should be ending as the strongest low level jet shifts
east, and additional strong winds should generally be higher
than the 2000 ft threshold. A pair of fronts will cross the area
this morning: the first will shift winds to the west around
sunrise, then the second will bring gustier winds from a more
northwesterly direction during mid to late morning. Expect
20-25 kt gusts through the afternoon, possibly a few to 30 kt.
Winds will diminish with sunset this evening.

Passing high pressure moves winds back to the south Monday
afternoon. A warm front may bring some light precip late Monday
night into early Tuesday morning. A brief period of snow or
sleet is possible, especially at BWI/MTN, but may not produce
much of an impact. Otherwise precip will be very light
rain/sprinkles if it occurs. MVFR ceilings may develop Tuesday
into Tuesday night, with the highest chance at MRB. Winds will
become westerly Tuesday evening behind a cold front.

VFR conditions return Wednesday (Christmas Eve) as brief high
pressure settles over the region. Some light rain chances could lead
to temporary sub-VFR reductions late Wednesday night into
Thursday (Christmas Day) as a warm front pushes through. Winds
will remain light and variable Wednesday before turning to the
south and southwest late Wednesday night into Thursday. South to
southwesterly winds continue Friday with VFR conditions
returning as the warm front lifts north of the region.

&&

.MARINE...
South to southwest winds continue early this morning, with
marginal Small Craft Advisory conditions on the wider waters.
These winds should diminish toward sunrise with a shift to the
west as the first boundary moves through. A brief lull is
likely, but the second cold front will increase gusts during the
mid to late morning as direction becomes more northwesterly.
Advisories are in effect for all waters to capture this, with
gusts mostly 20-25 kt, though there could be some to 30 kt.
Winds will gradually diminish tonight, but advisories continue
into early Monday morning over the wider waters.

Another transient area of high pressure will bring a brief
period of lighter winds on Monday, shifting to the south in the
afternoon. Advisories in southerly channeling may be needed by
the second half of Monday night. Winds may show a gradual
decline Tuesday, with a cold front set to come through during
the evening. Some continuation of advisories may be needed into
Tuesday night, but it looks much more marginal in nature.

Northerly channeling could produce SCA conditions for most of
the waters early Wednesday before sub-SCA level winds return.
Sub-SCA level winds continue Thursday and Friday although brief
periods of SCA conditions are possible for portions of the
waters due to southerly channeling.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 11 AM this morning to 1 AM EST
     Monday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 11 AM this morning to 1 AM EST
     Monday for ANZ530-531-535-536-538>540-542.
     Small Craft Advisory until 6 AM EST early this morning for
     ANZ531>534-536-537-540>543.
     Small Craft Advisory from 11 AM this morning to 6 AM EST
     Monday for ANZ532>534-537-541-543.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...EST
AVIATION...ADS/EST
MARINE...ADS/EST