Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

564
FXUS61 KLWX 192044
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
344 PM EST Thu Feb 19 2026

.WHAT HAS CHANGED...
Lack of consensus from guidance on Sunday system results in very
minimal changes to the deterministic forecast. Winds have
trended upward in the Allegheny Mountains Friday afternoon and
evening.

&&

.KEY MESSAGES...
- 1) Low pressure tracking nearby brings a slight winter storm
  threat to the forecast area this weekend, followed by colder
  than normal temperatures early next week.

- 2) Cloudy, rainy, and foggy conditions are expected through
  Friday morning as a stalled front meanders nearby.

- 3) A cold frontal passage may bring strong winds to the
  mountains Friday afternoon and evening.

&&

.DISCUSSION...
KEY MESSAGE 1...Low pressure tracking nearby brings a slight
winter storm threat to the forecast area this weekend,
followed by colder than normal temperatures early next week.

A high energy but low predictability pattern looms for late this
weekend. The pattern is forecast to be very amplified but in flux as
a deep upper-level low digs out of the Gulf of Alaska inducing a
downstream ridge-building event over the western U.S. This pattern
amplification in the vicinity of western North America comes with
low predictability due to data sparse regions over the North
Pacific. Meanwhile, a pair of downstream upper lows interact/merge
over Maritime Canada, with inherent low predictability with two
cutoff lows interacting.

If the upstream ridge-building event takes place a bit further west
near 120 W longitude on Saturday, downstream trough amplification
would be favorable for phasing over the mid MS Valley into the OH/TN
Valleys Saturday night. A subsequent low track hugging the coast
would become more likely in this scenario, aided by downstream
blocking and a potential source of cold air given the upper lows
over Maritime Canada and surface high pressure attempting to ridge
into northern New England.

There is an appearance of an inverted trough signature in a subset
of model guidance over the last couple cycles, given interaction
between a more amplified northern stream wave and a bit more distant
offshore southern stream low. This could factor into precipitation
amounts and placement.

Unfortunately, the 12z model suites did nothing to help try to nail
down a particular solution. On one end with the GEFS ensembles, we
have seen an upward trend snow probabilities. However, in the latest
EPS, the probabilities have dropped for portions of the area. Looking
just at 3" snow probs in this timeframe, EPS dropped around 5-10% on
average, while the GEFS jumped up significantly. The 12z Canadian
ensembles also trended down, and by a good bit more than the EPS. I
think this may ultimately translate to a net-zero change when it
comes to the afternoon run of the NBM, but it will take some time to
get that information, which may be elaborated more in the evening
discussion.

As described above, there are a substantial number of very complex
variables at play here, and all of them have to come together at
just the right time in just the right place in order for us to get
snow, and especially significant snow. At present, there are three
scenarios at play here.

 1) The phase of all of these upper level features occurs too late,
    with low development offshore and too far southeast.

 2) Similar to scenario 1, but an inverted trough on the back side of
    the low brings snow to eastern portions of the region.

 3) Low develops closer to shore and strengthens along Delmarva
    Peninsula, resulting in the most snow for our areas.


Exactly how all this occurs will be the difference between a couple
of strung out waves passing through with little fanfare, a modestly
impactful period of snow showers, and a more significant wintry
precip event. We are firmly in the "wait and see" period with this
storm, so just take precautions now, should the worst case scenario
play out. Having a preparedness kit stocked up is never a bad idea.

Lastly, no matter what plays out further east, it seems much more
likely that the mountains will see another round of upslope snow.
The key here will be with how much we manage to get. That will
depend on the storm track as well, but it seems much more likely for
at least advisory level accumulations through the Sunday/Monday
period along/west of the Allegheny Front.

Of note, the higher sun angle later in the season becomes a factor
especially for lower elevations if precip occurs during the day.
Cold air will also filtering into the region as the storm in
question approaches, rather than being locked-in beforehand, which
offers another layer of uncertainty in p-type.

Regardless of exactly how the details of the Sunday-Monday system
play out, another shot of below normal temperatures is favored for
early next week. Currently, high temperatures in the 40s (30s in the
mountains) with lows in the 20s (teens in the mountains) are
forecast through Tuesday night, with some midweek moderation
after.


KEY MESSAGE 2...Cloudy, rainy, and foggy conditions are expected
through Friday morning as a stalled front meanders nearby.

The front has pushed south and west of most of the forecast
area, resulting in a cool and dreary afternoon. Rain has been
filling in as warm advection increases over the boundary and a
vort max approaches. Expect fairly widespread rain into the
early evening hours thanks to this lift. There`s even some
convection west of the Appalachians, but little if any thunder
will make it to our forecast area. A relative dry slot will move
overhead later this evening into the early overnight hours as
the initial wave exits the area. Rain may decrease in coverage
and intensity, but some drizzle may persist as overrunning
continues. Remnant convection from today`s severe weather threat
in the Ohio Valley will reach the area late tonight into Friday
morning. Severe weather isn`t expected locally, but a few
thunderstorms could reach the Allegheny Mountains before they
outrun the elevated instability. However, this activity could
result in some briefly heavier rain rates. Storm total rainfall
amounts will be one half to one inch for many areas, with the
greatest potential for higher totals closer to the Allegheny
Mountains. WPC has a Marginal Excessive Rainfall Outlook in this
area. However, we have already seen most of the snow pack melt
in our area, and ice has been breaking up on rivers. Thus this
amount of rainfall is unlikely to cause too many issues. Most of
the rain should push out of the area by noon Friday.

The other issue is fog. While still reduced, surface
visibilities have been rising through the day and will likely do
so further with any steadier rain. However, cloud bases around
300-400 ft AGL are intercepting the ridges, resulting in low
visibilities. Fog could become dense in the dry slot tonight,
but otherwise, elevation based issues will continue. Some fog
could form near the colder bay waters again as well.
Visibilities will improve from west to east on Friday.

Even after the rain clears out, a cold air damming wedge may
persist over portions of the area until the cold front shifts
the wind to the west later in the afternoon and evening. Thus
low clouds may take some time to clear out, especially northeast
of the Potomac River. This will make the difference between
highs in the 40s versus 60s.


KEY MESSAGE 3...A cold frontal passage may bring strong winds to
the mountains Friday afternoon and evening.

Low pressure moving through the Great Lakes will send a cold
front toward the area Friday afternoon. Wind fields have been
trending stronger with the frontal passage, especially along the
Allegheny Mountains. Gusts could reach 40-50 mph on the ridges
Friday afternoon into Friday night, which could cause some
isolated/minor damage. There`s also a signal in some guidance
that these strong winds could downslope into the lee (US 220
corridor) during the evening hours. Further east, more stable
low level conditions are expected, so winds will remain
relatively tame besides on the higher ridges.

Lighter winds are expected Saturday as the front pushes south of
the area and stalls. Cold advection will be gradual, and above
normal temperatures are expected areawide under partly to mostly
sunny skies.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
While visibilities may improve at times this afternoon, flight
conditions will remain IFR or LIFR straight through Friday
morning due to low ceilings. Occasional rain can be expected
through early evening, then there may be a bit of a dry slot for
part of tonight. Drizzle could still occur at times, and it`s
possible fog could also worsen. Remnant convection from the Ohio
Valley will move through late tonight into Friday morning. While
it`s unlikely any thunderstorms reach the TAF sites, there could
be some briefly heavier rain rates. The rain will exit by midday
Friday. However, low ceilings may persist into the afternoon,
especially for the metro terminals, as the warm front may still
not lift north. Overall winds will remain northeast to southeast
at 10 kt or less. If the warm front lifts north, winds will
shift to southerly before the cold front reaches the area during
the late afternoon or evening. West winds will follow this
front. Winds will also increase aloft with the frontal passage,
but the low levels will be relatively stable, so can`t rule out
some LLWS during this period.

VFR conditions with light west winds can be expected Saturday.

Sub-VFR conditions appear likely on Sunday, regardless of the exact
storm track that takes place with the area of low pressure sliding
by to our south. The big question will be "how much snow?". It is
still too early to tell if we get any snow, and how much, but the
most likely time period for snow would start late Sunday evening and
into Sunday night. At this point though, there is still a good
chance for an all rain event as well, especially if the system
develops too far offshore. In that scenario, we may not even see
severe restrictions. With the level of uncertainty, this storm could
cause restrictions through Monday as well, but right now would favor
clearing by the afternoon.

&&

.MARINE...
The main concern through Friday morning will be fog.
Visibilities are relatively higher this afternoon with
occasional rain. However, probabilities are pretty high tonight
that visibility will drop back below 1 NM. Another round of
moderate rain will move through late tonight into Friday
morning. Should see improving conditions by afternoon. Otherwise
northeast to easterly winds can be expected through tonight.
Gusts may approach advisory criteria this evening, but appears
to be marginal/brief. The warm front could shift winds back to
the south Friday afternoon before a cold front brings another
shift to the west during the evening. While a brief period of
near-SCA winds is possible Friday night, this is likely to be
sporadic enough to not warrant a Small Craft Advisory. Lighter
west winds are forecast Saturday.

A potentially strong low pressure system will slide by to our south
Sunday into Monday. There is a lot of uncertainty at this time, but
should this system track closer to our region and strengthen early
enough, some significant marine winds are possible. SCAs appear
likely at this time, but couldn`t completely rule out Gales in that
period too. However, that will largely be driven by the
track/strength of the low, which it is just too early to tell at
this time.

&&

.TIDES/COASTAL FLOODING...
Sensitive locations are likely to reach Action Stage during
high tide through Friday night before tides decrease a bit
through Saturday night behind a cold front. Greatest chance of
reaching minor flood stage will occur at Annapolis Friday
evening. Tides are uncertain with potential coastal storm Sunday
into Monday given divergent model solutions on the
track/strength. While some tidal flooding can`t be ruled out, a
more probable outcome is that strong north winds could result
in crashing tide levels.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

DISCUSSION...ADS/CJL
AVIATION...ADS/CJL
MARINE...ADS/CJL