558
FXUS61 KLWX 081603
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1103 AM EST Wed Jan 8 2025

.SYNOPSIS...
Upslope mountain snow showers, cold temperatures, and breezy
conditions look to continue through Thursday as a strong Arctic
high pressure slowly builds back into the region. Another area
of low pressure will likely impact the region late Friday into
Saturday with the potential for wintry precipitation. High
pressure briefly returns Sunday before another frontal system
impacts the area early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Mid-morning update: No major changes have been made to the
previous forecast. Previous discussion follows...

Snow showers along the Allegheny Front will continue through
the day today. There will be periods of lighter snow through the
daytime hours before a trough axis digs further south later
this evening, leading to a potentially heavier bout of snow
across the higher terrain into Thursday morning. Snow ratios
will be 20:1 to 25:1 across the Alleghenies which coupled with a
few hundredths of an inch QPF will allow for increased rates at
times during the period. Winter Weather Advisories remain in
effect across the aforementioned areas but we cannot rule out an
upgrade to Winter Storm Warnings for portions of the area
should the anticipated totals over the 12 to 18 hour period
prove worthy of it.

Winds will continue to be gusty out of the northwest, especially
along the ridges and higher terrain. Cannot rule out gusts up to
50 mph along the Allegheny Front with 20 to 35 mph gusts
possible across the lower elevations, especially later this
afternoon. Dry conditions will persist east of the mountains
with highs in the mid to upper 20s for most areas aside from
parts of central VA and southern MD that could be flirting with
32 degrees for a few hours. Overnight lows tonight will be some
of the coldest of the season, with air temperatures getting down
into the teens along the lower elevations and single digits for
the mountains. With the frigid temps coupled with elevated
winds, winds chills tonight will be flirting with zero across
most areas and well into the negative teens across the
mountains. A Cold Weather Advisory has already been hoisted for
the Blue Ridge zones but further expansions may be needed.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
The Winter Weather Advisory for the Alleghenies will continue
into Thursday with upslope snow persisting across the area.
Additional accumulations of 2 to 5 inches will be possible
through this period with locally higher amounts across the
highest elevations. Winds will remain gusty one more day on
Thursday with northwest gusts 25 to 35 mph possible along the
lower elevations and up to 50 mph for the higher terrain. Wind
Advisories may be needed for some of the higher ridges east of
the Alleghenies during this time. Winds will gradually decrease
heading into Friday morning with overnight lows a degree or two
cooler compared to tonights forecasted temps.

High pressure briefly builds in on Friday, leading to drier
conditions across the mountains but it will be brief as the next
low pressure tracks further northeast towards the Mid-Atlantic
late Friday night. There is increasing confidence in a light
snowfall event for the Mid-Atlantic, leading to light
accumulations for areas, especially our southern areas. This is
where the moisture axis will be most abundant during that time.
Guidance continues to have some discontinuity in the track of
the low which would affect snow totals and any impacts related
to this system locally. Timing of the system looks to be late
Friday night into early Saturday. Continue to monitor our
forecast at weather.gov/lwx/winter.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Precip from the progressive Fri/Sat system will be on its way out
Saturday morning, though possibly lingering along the Alleghenies
into the afternoon. Gusty NW winds behind the system on Saturday
may result in wind chills in the teens and single digits overnight.

High pressure is expected to swiftly move in on Sunday, keeping cold
temperatures in place and mostly dry conditions. High temperatures
remain in the 30s for most of the area through the extended, and 20s
in the mountains. Lows will generally be in the teens and 20s,
Sunday night being the coldest with high pressure overhead.

An area of low pressure is expected to pass to our north Monday into
Tuesday, bringing another shot of upslope precip to the Alleghenies.
With temperatures in the teens and 20s, this will likely be in the
form of snow.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions look to continue through Thursday for all terminals
outside of the Allegheny Front. Wind looks to be the biggest
concern to aviation through Thursday. Northwest wind gusts
20-30 knots are possible this afternoon. Gusts of 25 to 35
knots are possible in the wake of a departing shortwave trough
Thursday. Highest gusts will be confined from late morning
through the early evening hours through Thursday. VFR
conditions and northwesterly winds are expected on Friday. Sub-
VFR conditions may be possible Friday night into Saturday
morning in association with low ceilings and snow.

Sub-VFR conditions likely continue into Saturday morning. Conditions
should improve quickly by Saturday afternoon and continue into
Sunday as high pressure builds in. NW winds could gust 15-20 kts
Saturday afternoon into the evening. Winds gradually diminish
heading into Sunday.

&&

.MARINE...
A prolonged period of SCA conditions is expected through
Thursday. Gusts mainly around 20-25 knots, and up to 30 knots
possible. A brief period of gales may be possible over portions
of the waters early Thursday into Thursday afternoon. A Gale
Watch has been hoisted for our lower zones of the Chesapeake Bay
and Tidal Potomac River during this period. Sub-SCA northwest
winds are expected on Friday as brief high pressure sits nearby.

SCA conditions are possible Saturday with gusty NW winds behind the
exiting system as high pressure builds in. Winds will gradually
diminish but could persist into Sunday morning.

&&

.TIDES/COASTAL FLOODING...
Strong offshore flow is expected to persist through the rest of
this week. As a result, water levels are likely to steadily
drop over the next several days, and reach low water threshold
(-1 FT MLLW) across much of the Tidal Potomac and Chesapeake
Bay. Mariners should be especially aware of low water during low
tides this week to avoid running aground.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 7 PM EST this evening for MDZ008.
     Winter Weather Advisory until noon EST Thursday for MDZ001.
     Winter Weather Advisory until 11 AM EST Thursday for MDZ501.
VA...Winter Weather Advisory until 11 AM EST Thursday for VAZ503.
     Cold Weather Advisory from 11 PM this evening to 9 AM EST
     Thursday for VAZ507-508.
WV...Winter Weather Advisory until noon EST Thursday for WVZ501-503.
     Winter Weather Advisory until 11 AM EST Thursday for WVZ505.
MARINE...Small Craft Advisory until 7 PM EST this evening for
     ANZ530>543.
     Gale Watch from 7 PM EST this evening through Thursday
     afternoon for ANZ533-534-537-541-543.

&&

$$

SYNOPSIS...ADM
NEAR TERM...KJP/ADM
SHORT TERM...ADM
LONG TERM...CAS
AVIATION...ADM/CAS
MARINE...ADM/CAS
TIDES/COASTAL FLOODING...LWX