241
FXUS61 KLWX 310055
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
855 PM EDT Sun Mar 30 2025

.SYNOPSIS...
Low pressure will track into the Great Lakes tonight, and then
across southern Canada tomorrow, with a trailing cold front
moving through the area tomorrow night. High pressure will build
to our north for Tuesday and Wednesday, before another strong
area of low pressure tracks into the western Great Lakes on
Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Radar imagery as of 850 PM still depicted isolated to scattered
light showers out over the Potomac Highlands. This is starting
to decay at this point, as was anticipated, and is also lifting
northeast into PA. Largely, this only dropped about a tenth of
an inch or so in the "heaviest" of showers. This was because it
had to fight a lot of dry air at the surface.

This round of showers should clear the area in the next hour or
two, as it has been a bit slower to traverse the region than
initially thought. Dry conditions will return areawide for the
first half of the night. The bulk of the forecast area should
experience dry conditions through the second half of the night
as well, but decaying showers and thunderstorms from the Ohio
Valley may reach, and potentially pass over, the Allegheny Front
just prior to daybreak. Actually increased POPs a bit with this
morning round in the latest forecast update. Still only around
30 to 50 POPs, mainly in the north. Additionally, a stiff
southerly breeze and clouds will keep temperatures very warm
overnight, with lows in the 60s for most (50s in the mountains).

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
EVENING UPDATE: No significant changes were made to the timing
of thunderstorms tomorrow, but did add in some enhanced wording
to include damaging wind threat in the forecast text. No real
changes otherwise, so please refer to the previous discussion
below.

A potent shortwave and its associated strong area of low
pressure will continue to lift northeastward across Ontario and
Quebec tomorrow, while a trailing shortwave tracks from OK/AR
tomorrow morning toward the central Appalachians tomorrow
evening. A trailing cold front will extend southwestward from
the low over southern Canada, and track across the forecast area
from west to east during the first half of tomorrow night.

While some questions remain regarding how well decaying
convection from today`s storms in the Ohio Valley will hold
together, model guidance is in reasonably good agreement that
appreciable daytime heating should ensue late tomorrow morning
into early tomorrow afternoon. As a result, surface based
instability will develop, and storms are expected to form by
early- mid afternoon along a pre-frontal trough. There is still
a bit of spread regarding exactly where this pre-frontal trough
will set up, but most guidance has it oriented from southwest
to northeast, somewhere across central or western portions of
the forecast area. Environmentally speaking, most models show
around 500-1000 J/kg of MLCAPE, within what will be a well
sheared environment (around 40-50 knots of effective bulk
shear). Initially, a mixture of short line segments and
supercells may be possible, before upscale growth causes
activity to turn predominantly linear in nature. The primary
hazard should be damaging winds, but a few instances of large
hail or a tornado can`t be completely ruled out. SPC currently
has the bulk of the forecast area outlooked in a Slight Risk for
severe thunderstorms, with an Enhanced Risk clipping Central
Virginia.

Storms should initially develop around mid- afternoon
across central and western portions of the forecast area. Storm
motions will be off toward the north and east, but the zone
where storms are developing will gradually shift to the south
and east, reaching the I-95 corridor during the late afternoon
and evening hours. Storms will linger through the evening along
and southeast of I-95, before finally clearing southern Maryland
around or just after midnight as the system`s cold front moves
through. Northwesterly winds, falling temperatures, and dry
conditions are expected during the second half of the night.
Overnight lows are forecast to be in the 40s for most, with 30s
in the mountains.

Sunny skies and a north to northwesterly breeze is expected on
Tuesday as high pressure builds to our north. High temperatures
are forecast to reach into the upper 50s to mid 60s for most,
with upper 40s in the mountains.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Ridging will build over the East during the middle and second half
of the week leading to a warming trend with 80s expected again.
Moisture return will be underway Wed afternoon into Thu. Light
showers will be possible Wed night into Thu in the return flow
particularly in western areas, but are more likely Fri into Sat when
cdfnt will be moving slowly across the area and area gets into the
cool sector and multiple waves of low pressure move along stalled
frontal zone. After temps in the 80s Thu and Fri, expect temps to
cool down significantly for Sat and Sun and the following week.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Showers over the WV Panhandle and western MD will continue to
push off to the northeast as they continue to decrease in
coverage. The only impacted site was MRB, with showers failing
to reach any terminals east of the Blue Ridge. Removed
previously sent PROB30s with the afternoon/evening TAFs for this
evening.

VFR conditions continue for much of tonight. However MVFR
ceilings will be possible for a few hours late tonight/early
tomorrow morning around sunrise, before conditions return to
VFR tomorrow morning. There`s a slight chance for a shower
around sunrise tomorrow morning as decaying activity moves in
from the west. With the evening package, have included some
brief PROB30s for that into the 00z TAFs.

Better chances for showers and thunderstorms will move into the
area late tomorrow afternoon into tomorrow evening as a cold
front approaches from the northwest. Some of these storms may be
strong to severe. The 00z TAF package attempts to nail down the
most confident period of thunderstorms. There could legitimately
be a good 3 to 4 hours of thunderstorms in that 6 hour timeframe
between early/mid afternoon into tomorrow evening. There are
some questions with how far east storms will pop up, with MRB
being the least certain to actually see the worst. So, did a
PROB30 there rather than a TEMP, just to drive home the fact
that there is still a lot of uncertainty there. Storms may just
pop up too far east, leaving MRB with primarily showers.

The worst of the activity will depart the region by late
evening, with showers perhaps lingering into the early overnight
hours. Outside of thunderstorms, winds will be out of the south
tomorrow around 20 to 25 knots. With showers and storms
departing, VFR conditions will return during the second half of
the night. Winds will shift to out of the northwest behind the
system`s cold front during the second half of the night, perhaps
gusting into the 20 to 25 knot range once again.

VFR conditions and northwest to northerly flow are expected on
Tuesday. Gusty SW winds of 25 to 35 kt will be possible Wed and
Thu. Lots of clouds both days, but no cig restrictions are
expected.

&&

.MARINE...
SCA conditions are likely on and off through the day tomorrow
within southerly flow. Thunderstorms appear likely tomorrow
afternoon into tomorrow evening, with SMWs likely needed during
that time. Some storms could contain winds in excess of 50
knots, especially during the late afternoon throughout the
entire evening. Storms could even linger over the central Bay
and lower Potomac through midnight.

Winds turn northwesterly behind a cold front during the second
half of tomorrow night, and remain north to northwesterly during
the day Tuesday, with SCA level gusts lingering through Tuesday
morning.

SCA conditions likely Wednesday through Friday.

&&

.TIDES/COASTAL FLOODING...
Sensitive tidal locations such as Baltimore, Annapolis, and Havre De
Grace may reach Action stage as a strong cold front approaches the
waters. Strong southerly flow will lead to increased tidal anomalies
ahead of the frontal passage, with anomalies peaking on Monday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until noon EDT Tuesday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until noon EDT Tuesday for ANZ530>543.

&&

$$

SYNOPSIS...KJP
NEAR TERM...CJL
SHORT TERM...CJL/KJP
LONG TERM...LFR
AVIATION...LFR/CJL/KJP
MARINE...LFR/CJL/KJP
TIDES/COASTAL FLOODING...LWX

NWS LWX Office Area Forecast Discussion