Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

268
FXUS61 KLWX 200810
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
310 AM EST Fri Feb 20 2026

.WHAT HAS CHANGED...
00z guidance showing some better consensus when it comes to the late
weekend system although some spread remains in the overall track of
low pressure, precipitation type, and intensity. Added some thunder
west of the Blue Ridge for early this morning with low clouds, fog,
and drizzle lingering. Gradually clearing skies and breezy
conditions this afternoon.

&&

.KEY MESSAGES...
-1) Slight winter storm threat continues for the entire area Sunday
into Monday as low pressure tracks along/near the coast. Colder than
normal temperatures early next week.

-2) Low clouds, fog, drizzle, and pockets of rain/isolated
 thunderstorms through the morning commute. Turning breezy with
 some clearing this afternoon as a cold front pushes through.

&&

.DISCUSSION...
KEY MESSAGE 1...Slight winter storm threat continues for the entire
area Sunday into Monday as low pressure tracks along/near the coast.
Colder than normal temperatures early next week.

A high energy but low predictability pattern looms for the back half
of the 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 also 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.

After reviewing the 00z model guidance suite, some subtle
consistency has been noted although subtle uncertainty remains. Most
of the models has a low tracking up from GA/AL toward the NC
coast and off the Delmarva coast during the late Saturday night
into late Sunday timeframe. The question remains in the proximity
toward the coast along with cold air availability, and the overall
scope of the precip shield pending the placement/intensity of the
system. 25 to 50 miles could make a huge difference between seeing
little to no wintry precip or impactful precip, especially for those
east of the mountains where the confidence remains low due to
thermal issues especially below elevations of 1500 feet. The 00z
GFS/GEFS solutions have come down a tad, but still produce
measurements on the order of 10+" of snow over a large chunk of the
area. Meanwhile, the 12z EPS ensembles came up some, but at much
more conservative levels which align with deterministic runs of the
NAM, RDPS, GDPS, GEM, CMC, EURO/EURO AIFS, and UKMET. The
latest NBM also came up a bit and aligns with the majority
compared to the GFS/GEFS outliers, especially along and east of
I-95. With that said, the 6/12z model suites should put the
remaining puzzle pieces together as we will sit 60 hours from
the event.

Three scenarios remain:

 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.

We still remain 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 to perhaps warning 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 be 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...Low clouds, fog, drizzle, and pockets of
rain/isolated thunderstorms through the morning commute. Turning
breezy with some clearing this afternoon as a cold front pushes
through.

The cool air wedge remains this morning as a stalled front waivers
nearby. The stationary boundary sits south the VA/NC border with a
warm front arcing north through central WV into western PA. Waves of
rain continue to traverse this boundary with even a few embedded
thunderstorms as dying convection pushes east from the Ohio River
Valley. Expect scattered showers and perhaps an isolated
thunderstorm (mainly west of the Blue Ridge) through the early
morning commute. An additional tenth to a quarter of an inch of rain
is possible from the activity this morning with locally higher
amounts across the Alleghenies where the bulk of the heavy rain
resides. Some rises will be noted on smaller streams and creeks
along and west of the Alleghenies given residual snow/ice melt.

Outside of the showers this morning, low clouds, fog, and drizzle
remain given the added saturation from the surface all the way
through the mid levels of the atmospheric column. This was evident
in both the IAD and RNK 00z soundings. As of 250am seeing more in
the way of low stratus with areas fog, especially where the dry slot
has taken hold. This is especially true south of I-66/US-50 and
toward areas along and east of I-95 closest to the bay/tidal Potomac
moist air over cold waters). Visibilities will improve this
afternoon and evening as low clouds lift with a cold front pushing
through.

The front will bring an end to the rain by late morning into midday
with increased winds over the higher ridges of the Alleghenies.
Gusts could reach 40-50 mph (western Allegany, western Grant,
western Pendleton, and western Mineral counties) this afternoon into
late evening, which could cause some isolated/minor damage given the
saturated ground. There`s still a signal in some guidance that these
strong winds could downslope into the lee (US 220 corridor (i.e
eastern Allegany, Hampshire, Hardy, Morgan, eastern Grant, and
eastern Pendleton counties)) during the evening hours. Further east,
more stable low level conditions are expected, so winds will remain
relatively tame with gust of 15 to 25 mph along and directly behind
the front this afternoon and into the evening hours. Lighter winds
are expected Saturday as the front pushes south of the area and
stalls.

Highs today will range from the mid to upper 40s over northeast MD
where low clouds will hang on the longest to near 70 across the
central VA Piedmont/Shenandaoh Valley. Similar values are expected
Saturday although slightly cooler over (in the mid 50s and low 60s)
central VA/Shenandoah Valley due to gradual cold air advection.
&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Widespread LIFR to IFR conditions look to continue across the
terminals through at least 15z/10am this morning. This is largely
due in part to low ceilings, areas of fog, and drizzle over the
region. Pockets of light to moderate rain look to impact the
terminals north of I-66/US-50 over the next 2 to 4 hours. Light to
moderate rain intensity is expected with perhaps a rumble of thunder
or two mainly west of KMRB. Rain will exit by mid to late afternoon
from west to east across the area. However, low ceilings may persist
into the afternoon, especially for the metro terminals, as the warm
front may not fully lift north through the region. BWI/MTN have the
greatest confidence of holding low ceilings through 19z while
IAD/DCA could see improvements a bit sooner based on the placement
of the boundary. Winds will remain light out of northeast switching
to southeast at 10 kts or less. If the warm front lifts north, winds
will shift southerly before the cold front reaches the area during
the late afternoon or evening. Gusts of 15 to 25 kts are possible
along and behind the boundary. Downslope westerly winds will follow
this front. Winds will also increase aloft with the frontal passage,
so have introduced low-level shear groups at the KIAD, KDCA, and
KBWI this evening into the front half of the overnight between 02-
07z/9pm-2am.

VFR conditions return briefly Saturday with light west winds
expected. Next chance of sub-VFR arrives with a coastal low pressure
system passing to the south Sunday into Monday. This system could
bring snow to the region, but exact amounts remain uncertain based
on track and intensity. The most likely time period for impacts from
snow would be late Sunday evening and into Sunday night. At this
point, there is still a good chance for an all rain event a,
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. VFR
conditions return briefly Tuesday before another system mid next
week.

&&

.MARINE...
Marine Dense Fog Advisories remain in effect through 7am this
morning for vsbys less than 1 nautical mile. Light to moderate rain
should move over northern/middle portions of the tidal
Potomac/Chesapeake Bay allowing visibilities to briefly improve
later this morning into midday. Further improvement can be expected
this afternoon and evening as cold front cross the waters. Gusts may
approach advisory criteria later this afternoon into early evening,
but appears to be marginal/brief (4 hour window or less). This
threat will most likely be covered by a Marine Weather Statement
over a Small Craft Advisory given the sporadic nature of the wind
along and behind the front as it pushes through. 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 tonight before tides decrease a bit Saturday behind a
departing cold front. Greatest chance of reaching minor flood stage
will occur at Annapolis this 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...Dense Fog Advisory until 10 AM EST this morning for MDZ008.
VA...None.
WV...None.
MARINE...Dense Fog Advisory until 10 AM EST this morning for ANZ530>543.

&&

$$

DISCUSSION...EST
AVIATION...ADS/CJL/EST
MARINE...ADS/CJL/EST
TIDES...LWX