Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

824
FXUS61 KLWX 041900
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
200 PM EST Wed Feb 4 2026

.WHAT HAS CHANGED...
Winter Storm Watches have been issued for the western Alleghenies
late Friday morning through Saturday morning. Gale Watches have
been issued for all waters Saturday morning into Saturday night.
Additional wind and cold weather headlines will likely be needed
(as confidence increases)for the remaining area late Friday into
Saturday.

&&

.KEY MESSAGES...
- 1) Near-Blizzard conditions possible in the Alleghenies late
  Friday morning through Saturday morning.


- 2) Increasing confidence for wind and cold weather headlines
  Friday night into the weekend.

- 3) Light (on and off) wintry precipitation expected to
  continue across portions of the central Shenandoah Valley
  into southern MD through early Thursday morning.

&&

.DISCUSSION...
KEY MESSAGE 1...Near-Blizzard conditions possible in the
Alleghenies late Friday morning through Saturday morning.

Confidence has increased enough to warrant the issuance of a
Winter Storm Watch for portions of the Alleghenies (Garrett,
western Grant, western Pendleton Counties) from Friday morning
through Saturday. Upwards of 4-6" of snow are likely, with
significant impacts from blowing and drifting snow. Travel
disruptions are likely along I-68/US-40 west of Frostburg, MD,
US-219 from the PA/MD line south to the WV line, US-48 west of
Moorefield, WV, US-33/WV-28 west of Franklin, WV, and US-250
west of Monterey, VA. The probabilities for 6 inches of snow
remain between 50 to 80 percent, with probs at or just below
the 30 percent for 8 inches on the western favored slopes (i.e
Backbone Mountain, Piney Mountain, Marsh Mountain, Keysers
Ridge, Bear Rocks, North Fork Mountain, Spruce Knob, etc.).

With plenty of instability within the DGZ and Arctic air
rushing in behind the Arctic front expect increasing SLRs during
the event. SLRs look to start around 15:1 Friday afternoon
increasing to 25:1/30:1 Friday night into Saturday morning when
the bulk of the moderate to heavy snow looks to fall. Snow is
going to be hard to measure due to strong winds causing drifts
and blow snow. Winds in the mountains ramp up late Friday
afternoon into Friday evening as the Arctic front and upper
level trough begin to pivot through. The strongest winds look to
arrive Friday night into Saturday in the wake of the front and
trough swinging through. The combination of gusty winds and
moderate/heavy snowfall could lead to near blizzard conditions
at times across the mountains. Expect a reduction in visibility
below 1/4 mile under heavier bands of snow streamers/squalls
along with gusts up to 50 mph (locally higher along the ridges).

Areas further east also have the potential to pick up on a
dusting to perhaps one inch of snow as the Arctic front sweeps
through. This is due in part to snow streamers/squalls that make
there way over the mountains. FROUDE numbers remain less than 1,
which means limited blocking within northwesterly flow. One
thing that remains uncertain is how much of a moisture fetch
there is off of Lake Erie and Lake Huron since they are mostly
frozen over. Yes, moisture will funnel in from the south ahead
of the boundary, but what is left to be tapped into in the wake
of the front when the highest snow squall parameter is maximized
(as the trough swings ) through remains in question.

The probabilities for at least 0.1" of snow remain at 60-90
percent across areas mainly along and north of I-66/US-50. This
indicates we could see those streamers and/or snow showers reach
the DC and Baltimore metros sometime Friday late afternoon to
evening. The probabilities trickle down into the 30 to 50
percent range further south. The probabilities for 1" are at 10
to 20 percent probs east of the mountains during the Friday
night into Saturday timeframe. Favored areas for a dusting-1"
would be Parr`s Ridge, Catoctin Mountains, South Mountain,
Sideling Hill, and other higher ridges of the Potomac Highlands.
More on snow amounts at weather.gov/lwx/winter.

KEY MESSAGE 2...Increasing confidence for wind and cold weather
headlines Friday night into the weekend.

A very strong pressure gradient will set up over the area in the
wake of the cold front/potent upper level trough late Friday into
much of Saturday. Blocking high pressure to the north and west
combined with strengthening low pressure off the Atlantic coast will
further exacerbate the magnitude/intensity of winds between 850
and 925 mb (winds greater than 40-60 kts). Expect a very sudden
onset of winds sometime early Saturday morning just before
daybreak. This is when the axis of the upper trough digs into
the Appalachians / northern Mid-Atlantic. Model geopotential
heights have a very wavy pattern over the mountains, which
indicate high likelihood for breaking lee waves that could mix
down stronger winds just off the surface. Even as the trough
quickly pushes east Saturday afternoon, very strong pressure
rises / CAA with a high building in from the west will support
windy conditions the entire afternoon to evening. The biggest
question is how much of this wind mixes down to the surface,
especially during the daylight hours Saturday when deeper
mixing is maximized.

Current guidance suggest two surges of wind, one with the
front/trough Friday night and a secondary surge with the
pressure rises Saturday. Confidence continues to increase for
the need for wind headlines over both land and water. Highest
confidence for wind headlines right now appear to be in the
mountains where probs for 40 to 50 mph gusts remain above 50
percent. Lower probabilities have also been noted further east
of the mountains and toward the I-95 metros generally running
between 15 to 20 percent for 50 mph gusts and 70 to 80 percent
for 40 to 45 mph gusts.

The most likely scenario at this time is steady gusts of 35-45
mph with occasional gusts of 50-60 mph, with up to 60-70 mph
over and just downwind (on the eastern slopes) of the mountains
(Catoctins, Blue Ridge, Alleghenies).

On top of the wind, will come the dangerously cold temperatures and
frigid wind chills. Look for lows back in the single digits and
teens Friday night with highs Saturday struggling to get out of the
teens and mid 20s (single digits mountains). Lows Saturday night
areawide with below zero values over the mountains. You combine the
Arctic air temperatures with the wind to get widespread subzero
wind chills late Saturday afternoon into early Sunday morning.
Cold Weather Headlines will likely be needed to encompass this
threat with wind chills east of the mountains between 0 and -10
degrees and -20 to -30 degrees over the mountains. These values
slowly improve Sunday as winds/gradient begin to relax.

KEY MESSAGE 3...Light (on and off) wintry precipitation expected
to continue across portions of the central Shenandoah Valley into
southern MD through early Thursday morning.

An additional weak impulse of energy will traverse the area to the
south this evening into tonight bringing another round of light
wintry precipitation across far southern portions of the forecast
area. This is associated with a southern stream trough that will
pass to the south. At the surface, low pressure will move into the
Carolinas with an inverted trough stretching northward into the Mid-
Atlantic region. These features will support additional light winter
precipitation chances later this evening across the far southern
Shenandoah Valley and south-central VA Piedmont before drifting
toward the northern neck of VA late tonight. Temperatures will once
again remain around freezing before falling into the upper 20s as
the system departs during the pre-dawn hours Thursday morning. Main
precipitation type appears to be snow although some rain may mix in
on the northern neck of VA at the onset. Any accumulations will be
light and limited to elevated/colder surfaces with a dusting to
perhaps 1" expected.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR conditions are expected across most of the terminals with
perhaps a brief period of MVFR cigs down around KCHO and KRIC late
tonight into Thursday morning as a weak wave of low pressure passes
to the south. Brief high pressure returns Thursday with no hazardous
weather expected for aviators through Friday morning. Winds
will remain out of the north at 5 to 10 kts with occasional
gusts up to 20 kts at times this afternoon. Winds will remain
light out of the north tonight into Thursday with speeds less
than 15 kts. Winds will change to the south Friday ahead of an
Arctic cold frontal boundary.

Sub-VFR conditions associated with a strong Arctic front will likely
start to impact terminals by late afternoon Friday, with elevated
northwest winds following. Snow showers and some light
accumulating snow is possible at most of the terminals Friday
afternoon to evening. Beyond the snow, lower CIGs and VSBYs
will likely persist into early Saturday morning. Gusts up to
40-50 knots across terminals are likely for Saturday, then
quickly decrease Saturday night into Sunday.

&&

.MARINE...
SCAs continue for the open/ice free waters of the middle/open waters
of the Chesapeake Bay and lower tidal Potomac through Thursday
afternoon. Northerly channeling will lead to gusts up to 20 kts at
times. These advisories will need to be expanded through Thursday
evening with a brief lull in the winds late Thursday night into the
first half of Friday.

Winds turn south to southwest ahead of a powerful Arctic front
on Friday, but winds should stay below SCA levels, and could
actually be around or less than 5 kt. Expect a very sudden onset
of Gale conditions across all of the waters early Saturday
morning around sunrise. Winds will snap to the northwest,
increasing for around 10 kt gusts to 35-40 kt gusts. A Gale
Watch is now in effect Friday night into Saturday night for all
of the waters. Special Marine Warnings are likely to be needed
to message the sudden onset of dangerous winds. Occasional gusts
to Storm-force (50kt) are possible at times.

For ice free waters, freezing spray is going to be an issue, so
expect Freezing Spray and/or Heavy Freezing Spray products to
be issued. Winds quickly diminish Sunday, but likely won`t fall
below SCA levels until Sunday evening.

&&

.TIDES/COASTAL FLOODING...
Blowout tides are expected late Friday night through Sunday night.
Water levels as low as -2 ft MLLW are possible. Low Water Advisories
may be required. The ice covered waters of the northern/middle
bay and tidal Potomac could result in the potential for damage
to docks, moorings and etc., especially when blowout tides
result in significantly lower water levels.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Winter Storm Watch from Friday morning through Saturday
     morning for MDZ509-510.
VA...None.
WV...Winter Storm Watch from Friday morning through Saturday
     morning for WVZ501-505.
MARINE...Gale Watch from late Friday night through late Saturday night
     for ANZ530>543.
     Small Craft Advisory until 6 PM EST Thursday for ANZ533-534-
     537-543.

&&

$$

DISCUSSION...KRR/EST
AVIATION...KRR/EST
MARINE...KRR/EST
TIDES...KRR/EST