973
FXUS61 KLWX 270800
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Mon Apr 27 2026

.WHAT HAS CHANGED...
Based on observational trends, have lowered visibilities across
areas currently seeing patchy fog. Also, have continued to
adjust the cloud forecast based on the westward erosion of the
stratus deck. While Wednesday`s thunderstorm chances have
increased, it might still be a bit overdone by the models.

&&

.KEY MESSAGES...
1) Tranquil weather today before turning more unsettled with the
next frontal system on Tuesday into Wednesday.

2) Cooler and dry for most of Thursday through Sunday. A few
rain showers could accompany a trailing disturbance early
Friday.

&&

.DISCUSSION...
KEY MESSAGE 1...Tranquil weather today before turning more
unsettled with the next frontal system on Tuesday into
Wednesday.

The GOES-19 nighttime microphysics channel shows an area of low
stratus continuing to erode from east to west. Based on such
trends, any residual low clouds should dissipate within the next
couple hours across the Alleghenies. In the wake, a number of
locations off to the east have begun to report patchy fog, some
locally dense. Expect this theme to continue until just after
daybreak as low-level moisture gets trapped underneath nocturnal
temperature inversions.

The influence of high pressure stretching from New England down
the spine of the Appalachians is being felt with the colder
early morning temperatures. As of 07Z/3 AM, widespread readings
are in the 40s, with some spotty upper 30s as well. Expect a
chilly start to the day until the radiation inversion mixes out.
Thereafter, temperatures will warm through the day aided by a
deepening boundary layer. Despite the building of heights aloft
with the transient upper ridge, some warming will be negated by
the 1000-850 mb easterly onshore flow. After a day spent in the
50s, today`s high temperatures should rise into the mid 60s to
low 70s. Abundant sunshine is in the forecast before clouds
increase late in response to the next weather maker. Tonight`s
lows fall into the 40s again.

For early Tuesday morning, a residual mesoscale convective
system (MCS) is expected to approach from the Ohio Valley.
However, these features often track along the instability
gradient toward regions of higher CAPE. With the forecast
showing stable profiles over the local area, it is likely this
MCS dives toward the southern Mid-Atlantic. For the area
spanning the Alleghenies into the Shenandoah Valley, some
decaying showers and perhaps a rumble of thunder are possible
during the morning hours. However, the stability of the
atmosphere should win out here. Additional scattered showers can
be expected throughout the afternoon/evening hours as ripples in
the quasi-zonal flow push through. Highs on Tuesday are likely
to remain in the 60s underneath the thickening clouds.

The better chance for showers and some thunderstorms would be on
Wednesday as a brunt of the upper trough moves toward the
Eastern Seaboard. The accompanying frontal system pushes across
the area on Wednesday which provides a soaking rain to the area.
Total forecast amounts largely range from 0.50 to 1.00 inches
which should not cause any hydrologic concerns given ongoing
drought conditions. Surface-based instability remains on the
limited side, generally averaging around 250 to 500 J/kg.
Consequently, the coverage and intensity of any developing
thunderstorms should be subdued. Area-wide temperatures on
Wednesday should push into the mid 60s to low 70s before post-
frontal air arrives by the following day.


KEY MESSAGE 2...Cooler and dry for most of Thursday through
Sunday. A few rain showers could accompany a trailing
disturbance early Friday.

High pressure at the surface will build in across the region behind
a departing closed low pressure system Thursday through Sunday. Most
places will be dry with some morning cloud cover breaking for
afternoon sunshine nearly each day. Models, GFS and EURO, do hint of
a trailing disturbance behind the closed low that could sweep across
the region early Friday. This disturbance, combined with an upslope
component to a cool northwest wind, could spawn a few rain showers
to scattered parts of the region. Confidence as to who gets these
showers are quite low at this point. Temperatures will remain cool
each of the extended day forecast with highs in the middle 50s to
lower 60s.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
The westward retreating MVFR stratus deck has now moved west of
all area terminals. In the wake, a number of locations have seen
patchy fog develop. While not explicitly in the TAFs, will
continue to monitor in case this fog impacts any of the
airports. Otherwise, VFR conditions are expected through tonight
underneath mainly sunny skies. This comes with a light wind that
shifts from east/northeasterly over to southeasterly by tonight.

In response to the next system, showers and perhaps some
thunderstorms (especially Wednesday) will yield some
restrictions at times over the next couple of days. A soaking
rain is looking more likely for Wednesday which would favor a
more prolonged period of sub-VFR conditions. Wind fields largely
vary between southerly and southeasterly through Wednesday, with
afternoon gusts to around 15 to 20 knots. An eventual turn over
to westerly is expected by Wednesday night behind the frontal
system.

VFR conditions Thursday through Friday night. A few rain showers
could accompany a disturbance early on Friday but confidence on
occurrence and locations are low at this time. A brief sub-VFR
status could occur but not certain on which terminals could be
impacted. Winds northwest 15 to 20 knots Thursday, then 10 to 20
knots Thursday night through Friday.

&&

.MARINE...
Most of the marine waters are seeing a significant reduction in
winds. The one exception would be the southern-most waters which
are in Small Craft Advisories through 7 AM this morning. Recent
observations show this region is barely hitting 18 knots so this
product may be canceled early.

Gradients weaken through Wednesday morning which will keep winds
below advisory thresholds. The next ramp up would be Wednesday
afternoon ahead of an approaching cold front. A strengthening
southeasterly wind will likely require Small Craft Advisories
for Wednesday afternoon and through the night. By the overnight
hours, gusts up to 25 knots or so are possible.

Small Craft Advisories likely Thursday through Friday night.
Winds northwest 15 to 20 knots (gusts 25 knots) Thursday, then
northwest around 15 knots (gusts 20 to 25 knots) Thurday night
through Friday.

&&

.TIDES/COASTAL FLOODING...
Onshore flow continues through today as high pressure builds to
the north. Many locations will reach Action Stage during high
tide early this week, with Minor tidal flooding possible,
especially at Annapolis and Dahlgren. A couple other tidal sites
like Alexandria and Havre de Grace could get close during the
higher of the two astronomical high tides through Tuesday, too.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 7 AM EDT this morning for ANZ534-
     537-543.

&&

$$

DISCUSSION...BRO/KLW
AVIATION...BRO/KLW
MARINE...BRO/KLW

NWS LWX Office Area Forecast Discussion