Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

281
FXUS61 KLWX 170855
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
355 AM EST Wed Dec 17 2025

.SYNOPSIS...
High pressure near the Delmarva will continue to pull away from
the East Coast. Milder temperatures and dry conditions expected
through Thursday. A strong cold front will push through the
region Thursday night. Showers will develop with the frontal
passage, followed by gusty winds and colder temperatures once
again late week.

&&

.NEAR TERM /THROUGH THURSDAY/...
High pressure over us will weaken as a mid-level disturbance
pushes east across the Great Lakes today. A weak and dry cold
front will slide across the region but be barely noticeable
outside of a brief wind shift out of the north. Behind the
front, a second area of high pressure will build in through
Thursday morning. Highs today will top out in the middle to
upper 40s in the north and the lower to middle 50s in the south.
These are milder than recent days. Temperatures tonight will be
a few degrees milder and closer to average for mid-December.

The second high pressure will move east by midday Thursday to
make room for a developing warm front across southern Virginia
and north-central North Carolina to push northward midday
Thursday through Thursday evening. During the same time that
this warm front is pushing north, a potent upper level low
pressure system will be shoving eastward across the Lower Great
Lakes and Ohio Valley. Additional warmth and moisture will also
be streaming northward ahead of the main low pressure system and
just behind the advancing warm front. Some pre-warm frontal
rain showers are possible Thursday afternoon, but most likely
showers would be more prone to develop behind the warm front
and ahead of the approaching affiliated cold front Thursday
evening.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
During the late Thursday evening and overnight into early
Friday morning, showers are expected to develop ahead of a
powerful cold front. This will then be followed by a line of
gusty showers and perhaps a few thunderstorms accompanying the
front itself.

There are a lot of factors at play with this system that lend
at least some level of concern in terms of a low-end severe
weather threat. First off, there will be plenty of wind shear to
work with. A powerful, negatively- tilted, upper- trough will
swing through the region early Friday. This will be accompanied
by a 60-70 knots LLJ. In short, deep- layer shear values in
excess of 60 knots are forecast, with impressive curved
hodographs yielding low-level SRH values in the 300-400 m2/s2
range. However, a key component for sever weather is
instability, and this is going to be hard to come by given the
time of day this front rolls through. As guidance continues to
roll in this morning, my thoughts remain largely unchanged in
regards to the overall threat for the region. The most likely
scenario is that this line of heavy showers along the actual
front will bring some gusty winds down with it. This seems
reasonable given the amount of low-level winds at play here.
However, the magnitude is going to be greatly hindered by a very
steep inversion at the surface. While you can punch some winds
through the inversion given strong enough convection, very
rarely do you get all of that wind down. For that reason, my
best thinking is some 40 mph winds along the line of showers,
with a few gusts near 50 mph not out of the question, albeit
pretty isolated in nature. If there were a spot that is slightly
more favored, that would be across southern MD. As is often the
case, this area will see higher dew points than areas north and
west. This would be the area where the highest thunderstorm
threat would be, albeit still small. It is here that there is
some indication of a low-end tornado threat, but again this will
be very conditional on the fact that some instability is able
to develop. A few hi-res models do have some CAPE in that
region, but still thinking it will just not quite be enough to
spin up a tornado. At any rate, it can`t be completely ruled
out, so it is always a good idea to have a way to get warnings
overnight, should we have to issue any.

Behind the cold front, blustery conditions return for Friday
afternoon in strong northwest winds. Winds could gust 35 to 45
mph for most, especially north of the I-66 corridor roughly.
Wind gusts of 45 to 55 mph can be expected over the higher
elevations during this time, with Wind Advisories likely needed
in a future forecast package.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
High pressure quickly moves overhead on Saturday, then departs
offshore Saturday night into Sunday. Overall, conditions are
forecast to be dry and seasonal this weekend, with no significant
weather expected. A dry cold front quickly crosses the area on
Sunday, with some rain/snow showers possible in the Alleghenies on
the backside of the front. Due to temps right or just above
freezing, likely will not see accumulating snow. Another area of
high pressure builds in for the start of next week as temperatures
remain near seasonal values.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Modest LLJ develops near daybreak Wednesday which could result
in some LLWS across terminals. Not enough confidence to add
given we are on the southern periphery. Just something to
monitor. Previous discussion follows...

High pressure will provide dry and cold conditions through
tonight. Winds become southwest around 5 to 10 knots today into
Wednesday night. There could be a brief shift to northwest with
a passing dry weak front. For the most part, we can expect
gradual warming temperatures with a southerly wind ahead of
a powerful front set to push through late Thursday.

Sub-VFR conditions are possible Thursday afternoon as a front
approaches the terminals with restrictions likely during
precipitation overnight. Southerly winds gust 15 to 25 knots
Thursday afternoon and into the overnight ahead of the front.
Some convection is possible overnight, but more likely in the
form of a brief heavy downpours, especially along the actual
front early Friday morning. This could also be accompanied by a
surge of 40+ knot winds along the main line.

VFR conditions and gusty winds are expected across all terminals on
Friday in the wake of the cold front, with gusts likely exceeding
30 knots through the afternoon.

Winds diminish quickly Friday evening before becoming light
overnight.

VFR conditions are likely to persist across the area this weekend as
high pressure traverses the region. Winds could gust around 15-20
knots each afternoon, with southerly winds Saturday and westerly on
Sunday.

&&

.MARINE...
Southerly channeling over the middle Chesapeake Bay and the
southern end of the tidal Potomac have lead to an SCA being
issued through 1 PM this afternoon. Winds will taper off during
the evening into early Thursday.

Small Craft Advisories are likely beginning Thursday afternoon
as southerly winds gust 20 to 30 knots through the overnight
ahead of a powerful cold front. A brief surge of stronger winds
is possible along the cold front early Friday morning with a
line of heavy showers, and perhaps a few thunderstorms (mainly
in southern MD). However, a strong inversion is expected at the
surface, which could help to subdue this threat a bit. Right
now, couldn`t rule out some 40+ knot wind gusts along the line
early Friday morning.

Gusty northwest winds will yield high-end Small Craft
Advisories across the waters on Friday at the very least. In
the northern portions of the waters, north of North Beach,
winds could reach Gale-force, especially after mid-morning into
Friday evening.

As high pressure builds over the area, winds diminish Friday
night, becoming light by Saturday morning.

Southerly channeling is likely to produce SCA conditions across all
the waters Saturday evening into Sunday morning. Winds diminish
Sunday as high pressure moves offshore and a dry cold front moves
through the area. SCA conditions could return Sunday night as
northwest winds increase behind the front.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 1 PM EST this afternoon for ANZ533-
     534-537-541>543.

&&

$$

SYNOPSIS...CJL
NEAR TERM...CJL/CPB/KLW
SHORT TERM...CJL
LONG TERM...KRR
AVIATION...CJL/KRR
MARINE...CJL/KRR