Martinsburg, West Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

158
FXUS61 KLWX 031431
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
931 AM EST Tue Dec 3 2024

.SYNOPSIS...
Well below normal temperatures continue through Wednesday
morning as high pressure builds south of the region. A potent
area of low pressure will drag a strong cold front across the
area Wednesday night into Thursday. This brings mountain snow,
strong gusty winds, and colder temperatures to the area. High
pressure returns Friday into the weekend, which will bring a
gradual warming trend back towards normal temperatures.

&&

.NEAR TERM /THROUGH TONIGHT/...
Visible satellite as of mid morning shows a few rogue patches of
stratus across the piedmont, with more solid overcast along and
west of the Allegheny Front. Scattered snow showers were dropping
into western MD resulting in a quick coating in spots. This
activity should diminish through midday.

In the wake of a potent upper trough, which is pushing offshore
today, northwest winds will pick up a bit compared to the past
few days. Heights rise a bit today as an upper ridge begins to
push east towards the region. Additionally, strong surface high
pressure pushes through the TN River valley today and nearly
overhead tonight. This will lead to slightly warmer temperatures
today, though still below average. Winds gusting to around 20
to 25 mph will have it feeling like the low 30s for most (single
digits to low teens on the ridges).

Winds will drop off markedly overnight as high pressure moves
overhead. With clear skies accompanying the light winds, still
setting up to be the coldest night of this stretch with
widespread lows in the teens to low 20s. Rural portions of the
VA Piedmont and sheltered valleys west of the Blue Ridge likely
drop into the low to mid teens tonight.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The aforementioned upper-level ridge will be overhead on Wednesday
while high pressure pushes offshore. This will result in temps in
the mid 40s (30s in the mountains). For much of the day, winds
will remain light and turn out of the southwest ahead of an
approaching frontal system.

Looking upstream on Wednesday, a powerful upper-level trough
digs south out of central Canada late in the day into Wednesday
evening. The surface reflection of this upper-level system will
push a very strong cold front through the region Wednesday
night into Thursday. The increasing pressure gradient across the
Mid-Atlantic becomes noticeable by Wednesday afternoon as WAA
allows stronger winds aloft to begin mixing down to the surface.

South-southwest winds sustained at 10-15mph gusting 20-25 mph
are expected Wednesday afternoon, increasing to 25-30 mph gusts
Wednesday night. For the mountains, much stronger winds are
becoming increasingly likely, with Wind Advisories likely
starting Wednesday evening and continuing into the first half of
Thursday. High Wind Watches may be needed. One caveat is that the
winds may not quite be aligned with height, meaning there is
about a 20 to 30 degree directional change from the surface to
about 5 km. This could prevent those strongest values from
making it down. That being said, still forecasting peak gusts of
40 to 50 mph, with high end gusts up to 55-60 mph possible
along the highest ridges of the Alleghenies and Blue Ridge/
Catoctin Mountains.

Now for the precipitation side of the storm, which begins to
move into the area late Wednesday evening, ahead of a rapidly
advancing cold front. It likely is snow in the mountains and a
mix of rain/snow to the east, at least at the onset. The models
indicate strong CAA in the 850-925 mb layer Wednesday night,
that should allow precipitation to quickly transition to all
snow for most of the area after 12AM to 3AM Thursday morning.
The surface temperature forecast becomes a bit tricky at this
point, and will be critical for any potential impacts from any
light accumulating snowfall Thursday morning. Currently the most
likely areas that see temps drop to/below freezing are along
and west of US-15. Most recent model guidance hints at some
heavier elements making it far enough east to potentially be an
issue for the Thursday morning commute. Have maintained some
light accumulations all the way to the metro areas. Thinking
that with such a powerful front and upper-level forcing, that
there will be a few streamers that cause some issues across the
region. Temperatures will be marginal at this time (mid 30s or
so), but could still see a few issues on roads under any
moderate to heavy elements. All that being said, not looking at
much in terms of total accumulation outside of the mountains.
Current forecast calls for a trace to half an inch being the
most likely scenario and mostly on grassy surfaces.

In the mountains, things continue to trend snowier with each
run, so amounts have come up a good bit with this package. Very
cold air, and a deep moisture connection to the Great Lakes will
set the stage for a prime snow squall setup along the Allegheny
Front. Forecast snow amounts between Wednesday night and Thursday
morning are between 3 and 6 inches with potentially higher
amounts up to around 8 inches along the western-facing slopes
above 2500 feet.

One final aspect of this system to consider is the winds paired
with the snow, especially early Thursday morning. With an air
mass this cold, the snow/liquid ratios are going to be very
high, leading to a fine, powdery snow. This paired with the
aforementioned wind gusts could lead to whiteout conditions at
times. It will be treacherous to travel in the mountains
Thursday morning. This will likely even continue to be an issue
later in the day, even after the snowfall ends. With potentially
several inches of powdery snow on the ground, snow is likely to
blow around throughout the day, covering roads that have been
plowed and reducing visibilities.

Highs on Thursday afternoon outside of the mountains should be
in the 30s to low 40s for most, with sunny conditions returning
by late morning/early afternoon. Strong winds continuing
throughout the day will result in wind chills in the 20s for
most (single digits in the mountains).

As we move into Thursday night, cold air rushes into the region,
resulting in lows in the 20s (teens in the mountains). Winds
remain quite strong even overnight, so wind chills are going to
be the coldest of the season. For areas east of the Blue Ridge,
wind chills will drop into the teens. Further west, wind chills
drop into the single digits along and west of the Blue Ridge,
and even well into the negative single digits along the ridges.
Cold Weather headlines are possible in the mountains during
this time. Given the possibility of power outages from the
strong winds, it is important to make preparations now ahead of
this event and be prepared to find a way to stay warm.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
To finish out the work week, longwave troughing persists across
eastern sections of North America. The system from Thursday will
have already pushed into the province of New Brunswick in Canada by
Friday morning. This carries a sub-976 mb surface low farther into
the Canadian Maritimes while a strong anticyclone settles over the
Ozarks region. The net gradient formed by this 60 mb pressure
difference from Arkansas/Missouri to eastern Canada will maintain a
blustery environment across the local area. Forecast soundings show
mixing up to around 800-mb within the deep-layered northwesterly
flow. While winds at the top of the mixed layer decrease relative to
the previous day, gusts of 20 to 30 mph are possible as this higher
momentum air mixes to the surface. Forecast highs stay in the 30s
with a few spots hitting the 40 degree mark. The usual cold spot
will be in the mountains where teens to 20s are more likely. Adding
the wind to the mix should carry wind chills into the single digits,
with 20s to near freezing outside the mountains.

Although the Canadian high ends up southwest of the region, there
should be enough influence to help diminish winds some into the
night. Forecast lows drop into the 10 to 20 degree range, locally up
to 25 degrees along milder spots of the I-95 corridor. Winds remain
somewhat elevated along the Alleghenies which will carry wind chills
to around 0 degrees.

Northwesterly flow aloft continues into Saturday with models
trending toward a mostly dry day. The exception is the Allegheny
Front where some upslope snow showers are possible through the day.
Otherwise, expect a mix of clouds and sun across the remainder of
the area with highs in the upper 30s to mid 40s. A slow, but steady
warming trend ensues into subsequent days as heights build. Daily
temperatures push to near climatology by Sunday before low 50s
return to the forecast on Monday. This does come with increasing
rain chances as a southern stream system approaches from the
southwest. However, believe models are somewhat overdone with this
given the level of uncertainty. Thus, opted to cap the chances for
showers at around 50 percent.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected through Wednesday. Expecting breezy
Northwest winds gusting to around 20 to 25 knots this
afternoon. Winds then taper off overnight as high pressure moves
overhead and eventually offshore. This will turn winds out of
the S/SW heading into Wednesday.

A strong area of low pressure approaches the area late Wednesday
into Thursday, causing winds to increase once again, with gusts
of 20-25 knots out of the SSW likely Wednesday afternoon into
Wednesday night.

The significant wind surge comes along and behind the cold front
into Thursday morning. Winds will quickly shift out of the WNW
between 09z and 13z Thursday and increase to around 35 to 45
knots. Some snow is also possible on Thursday morning at all
terminals, especially at MRB, IAD, DCA, BWI, and MTN. CHO may be
a bit too far south to get any snow, but can`t completely rule
it out. There are even some indications that some streamers
could even drop some brief heavier snow in isolated spots.
Should one of these move over a terminal, could certainly result
in issues with VSBY and runway conditions, albeit briefly.

A dry forecast is in store for the terminals on Friday and Saturday
which will support VFR conditions. Blustery winds do persist on
Friday as a deep area of low pressure inhabits the Canadian
Maritimes. Northwesterly gusts during the afternoon could push to
around 25 knots before decreasing into the evening and night. Winds
shift to west-southwesterly by Saturday with gusts topping out
between 10 and 15 knots.

&&

.MARINE...
For now, marine headlines remain unchanged in regards to winds
today and the system late Wednesday into Thursday.

Gusty northwest winds are expected to continue across all the waters
through this evening before tapering off overnight as high
pressure approaches. Small Craft Advisories are in effect for
all the waters through just after midnight.

Winds drop below SCA conditions for a brief time period Wednesday
morning, then begin to increase substantially on Wednesday
afternoon as a strong area of low pressure approaches the
region. SCA conditions begin again Wednesday afternoon, with
south-southwest gusts of 20-25 knots likely, then increasing to
25-30 knots over most of the waters Wednesday night. Some gusts
to near gale force, around 35 knots, are possible over the open
waters of the bay. Do think the best chance for Gale-force
winds comes on Thursday as winds turn out of the NW as cold air
rushes in behind the aforementioned cold front. SCAs will
certainly be needed into Thursday night, but still not sure if
Gale conditions continue that long. For that reason, did not
decide to extend the Gale Watch at this time, but that may be
necessary at a later time.

A blustery northwesterly wind continues through Friday across the
area waterways. Southern portions of the Chesapeake Bay could near
gale force on Friday morning, but expect largely 25 to 30 knot
gusts. Winds do slowly decrease through the day with Small Craft
Advisories likely required through Friday evening, possibly into the
night for the southern Chesapeake Bay. Winds shift to west-
southwesterly as high pressure passes by to the southwest. Gusts
could near 20 knots at times, but confidence is low at this
time.

&&

.TIDES/COASTAL FLOODING...
The main period of interest will be Wednesday evening into Thursday
as a powerful cold front pushes across the area. Expect a marked
increase in water levels ahead of this system. This places a few of
the more sensitive locations into Action around the time of high
tide. In the wake of this boundary, a blustery westerly wind will
quickly lower water levels. Further drops are possible on Friday as
winds turn more northwesterly. During this phase on Thursday and
Friday, there is some potential for blowout tides.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 10 PM EST this evening for MDZ008.
     Small Craft Advisory from 11 AM Wednesday to 7 AM EST Thursday
     for MDZ008.
     Gale Watch from Thursday morning through Thursday evening for
     MDZ008.
     Winter Storm Watch from Wednesday evening through Thursday
     afternoon for MDZ001.
VA...None.
WV...Winter Storm Watch from Wednesday evening through Thursday
     afternoon for WVZ501.
MARINE...Small Craft Advisory until 10 PM EST this evening for
     ANZ530>532-538>540.
     Small Craft Advisory from 11 AM Wednesday to 7 AM EST Thursday
     for ANZ530>533-535-536-538>542.
     Gale Watch from Thursday morning through Thursday evening for
     ANZ530>533-535-536-538>542.
     Small Craft Advisory until 3 AM EST Wednesday for ANZ533-534-
     537-541>543.
     Small Craft Advisory from 11 AM to 6 PM EST Wednesday for
     ANZ534-537-543.
     Gale Watch from Wednesday evening through Thursday evening for
     ANZ534-537-543.
     Small Craft Advisory until 5 PM EST this afternoon for ANZ535-
     536.

&&

$$

SYNOPSIS...DHOF/CJL
NEAR TERM...DHOF/CJL
SHORT TERM...DHOF/CJL/KRR
LONG TERM...BRO
AVIATION...BRO/DHOF/CJL/KRR
MARINE...BRO/DHOF/CJL/KRR
TIDES/COASTAL FLOODING...BRO