692
FXUS61 KLWX 140053
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
853 PM EDT Sun Apr 13 2025

.SYNOPSIS...
High pressure will be pushed to the southeast tonight while a weak
disturbance moves overhead. A strong low pressure system will
move across the Great Lakes Monday, with a trailing cold front
pushing into the area Monday night. A reinforcing cold front
will push through early Wednesday, then high pressure will build
toward the area by Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Ahead of a low pressure system in the upper Midwest, an axis of
warm advection aloft will push into the area later tonight,
coincident with a vort max. Mid and high level clouds will
quickly increase later this evening. Guidance continues to show
very little in the way of measurable precipitation, given
largely mid level forcing and moisture. Some showers showing up
on regional mosaics across central WV, but don`t think that
means they will make it here. Any showers that do try to get
going will be battling 15-20 degree dew point depressions at
the onset. While just about anywhere could see a brief shower or
sprinkle, the highest chance in the mountains and toward the
Pennsylvania border. Clouds will have a stabilizing effect on
temperatures, with readings in the 40s for most.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The low will lift north into the Great Lakes Monday, with a
trailing cold front racing across the Ohio Valley, and
approaching the Appalachians by evening. The amount of
precipitation and saturation that occurs with the weak
disturbance tonight could play a role in convective potential
later Monday. While most guidance suggest there will be plenty
of mixed layer clouds around Monday and the effective warm front
may struggle to lift north of the area, some guidance supports
the day starting with thicker clouds and more low level
saturation across the northern half of the area. This would
result in a tighter thermal gradient as well as limit
instability to the north. Either way, most of the day should
remain dry outside of some upslope showers or drizzle along the
Allegheny Front. Convection originating from the Ohio Valley
likely won`t reach the forecast area until at least 5 PM,
and possibly several hours later. However, once it does, expect
fast storm motions moving eastward across the area.

There remains considerable spread with the environment and
resulting convection east of the mountains during the evening.
Height falls, steep mid level lapse rates, and convergence
along the warm front (and possibly a developing triple point
low) will provide support for at least some showers and
thunderstorms continuing eastward despite the initially capped
atmosphere, nocturnal cooling, and westerly/downsloping flow
component aloft. Hail will be a threat given the steep mid level
lapse rates and strong shear. The wind threat may be somewhat
dependent on low level stability, but at least some wind damage
could occur with any stronger storms given the strong wind
fields and fast storm motions. A non-zero tornado threat could
be present in the vicinity of the warm front. Heavy rain rates
are also possible. Even though individual storms will be fast
moving, enhanced totals are possible along the warm front with
more organized and prolonged storms possible. The threat for
thunderstorms should end between 11 PM and 2 AM, but some
showers could linger as the cold front progresses across the
area.

The strong upper trough digs over the area Tuesday, with the surface
pressure gradient tightening in response to the deepening low to our
north. Model soundings indicate nearly unidirectional deep westerly
flow. This is a favorable setup for strong winds aloft to mix
down to the surface, especially in the climo wind favored area
along/west of the Blue Ridge and along/north of I-66. Winds
could gust around 35-45 mph for most of the area, with 45-55 mph
gusts in the mountains Tuesday afternoon. Wind Advisories are
possible, with some of the higher-end ensemble guidance pointing
to High Wind criteria being met in the higher terrain.
Compressional warming brings highs up to the upper 50s and 60s
Tuesday afternoon.

More clouds than sun can be expected Tuesday with isolated to
scattered showers beneath the trough. While the area dries out
by Tuesday evening, cold air advection in the mountains results
in a transition to snow showers Tuesday night. Upper dynamics
look favorable on the backside of the departing upper trough,
with northwest winds advecting moisture off the Great Lakes.
Snow will be elevation dependent as the atmosphere slowly cools,
with generally an inch or less of accumulation most likely.
However, the higher ridges could see a few inches if higher
precipitation guidance were to verify. East of the mountains,
lows range from the mid 30s to mid 40s with gusty winds
continuing.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Dry conditions and gusty winds are expected on Wednesday in the wake
of a cold front departing the area. West winds gust 25 to 35 mph
during the day with locally higher gusts along the ridges. Wednesday
will be the coolest day of the long term period with high
temperatures in the 50s to low 60s (40s in the mountains)for most.
Overnight low temperatures fall into the 20s and 30s as winds
diminish throughout the night.

As surface high pressure builds overhead from the west through
Thursday, temperatures gradually warm each day. High temperatures
will be in the 60s for most on Thursday with those at higher
elevations staying in the 50s. Dry conditions continue through
Thursday night with overnight low temperatures dropping into the
upper 30s to 40s.

Precipitation chances return for the end of the week and into the
weekend as a low pressure system approaches from the west. A slight
chance to a chance of precipitation is expected both days.
Temperatures continue to warm, with highs on Saturday reaching the
mid 70s to low 80s.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Winds have diminished in the last couple of hours, with all TAF
sites now AOB 10 knots. A light shower or sprinkle could
briefly pass tonight as a mid-level feature pushes through the
region, but probabilities still at 20 percent or less at this
point. Either way, VFR conditions should continue tonight and
Monday.

Showers and some embedded thunderstorms are possible Monday
evening as a cold front approaches the area. Uncertainty remains
high with the severity and coverage of storms as they move east,
but strong winds, hail, and brief heavy rain will be possible.
The highest chance for storms will be at MRB, lowest at CHO.

After showers/storms wane late Monday evening, VFR conditions return
Monday night into Tuesday. The main concern for Tuesday is going to
be strong west winds that gust to 30-35 knots in the afternoon.
Winds remain elevated at 20-25 knots Tuesday night.

VFR conditions are expected Wednesday and Thursday as high pressure
builds overhead. Gusty W/NW winds are expected on Wednesday with
gusts 20 to 30 knots. Winds diminish overnight, with NW gusts around
15 knots expected Thursday morning. Light winds, blowing 5 to 10
knots, Thursday evening through the overnight.

&&

.MARINE...
Winds have quickly diminished in the past couple of hours, so
SCAs were allowed to expire around 7 PM. Winds remain below SCA
criteria through Monday evening. Direction gradually becomes
southeasterly then southerly ahead of an approaching frontal
boundary.

Isolated strong thunderstorms capable of producing wind gusts in
excess of 35 knots and hail are possible Monday evening.

A cold front moves through Monday night, then strong winds develop
behind the front on Tuesday. SCA conditions are likely, with gale
conditions possible Tuesday afternoon into Tuesday evening. A
Gale Watch has been issued where confidence is currently medium,
across parts of the northern bay and upper tidal Potomac. This
situation will continue to evolve. Strong gusts could be
augmented by showers as well, but confidence is currently low
for many showers developing Tuesday afternoon. Winds may
lessen slightly Tuesday night, but it`s not out of the question
they could remain near gale force.

Gusty northwest winds are expected in the wake of a cold front
Tuesday, with small craft advisories likely. Winds diminish
overnight with small craft advisories possible in the southern
portions of the waters through Thursday morning.

&&

.TIDES/COASTAL FLOODING...
Annapolis is forecast to reach action stage, and near minor flood
stage, during the high tide cycle Monday and Tuesday morning due to
southerly winds. Gusty northwest winds are expected in the wake of a
cold front on Tuesday, with tidal anomalies expected to fall.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Gale Watch from Tuesday morning through Tuesday evening for
     MDZ008.
VA...None.
WV...None.
MARINE...Gale Watch from Tuesday morning through Tuesday evening for
     ANZ530-531-535-538.

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS/CJL
SHORT TERM...ADS
LONG TERM...AVS
AVIATION...ADS/AVS/CJL
MARINE...ADS/AVS/CJL
TIDES/COASTAL FLOODING...AVS