507
FXUS61 KLWX 200052
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
852 PM EDT Tue Aug 19 2025

.SYNOPSIS...
High pressure to our north will continue to funnel cool and
moist air into the region off the Atlantic Ocean through
Wednesday. A cold front will approach the region Wednesday
before pushing through Wednesday night. This will help to drag
Hurricane Erin well offshore. Weak high pressure builds across
the region late in the week into Saturday. An area of low
pressure will track toward Hudson Bay over the weekend. The
associated cold front will move through early next week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
An onshore flow will continue through the night. Some drizzle or
a few showers will linger across southern Maryland and the
Chesapeake Bay. Low temperatures will drop into the 60s.

An approaching cold front and departing surface high pressure
to our northeast will result in a shift to southerly winds
across the region. Low clouds and patchy fog to start the day
Wednesday will give way to sun and then increasing clouds
through the day Wednesday. A warm front will lift into the
region before a cold front arrives and brings a couple of
showers and thunderstorms to the region. Highs Wednesday
afternoon should rise into the lower to middle 80s.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Previous discussion...
Showers will likely continue into Wednesday night with some
pretty decent moisture in place ahead of the front itself. As
this collides with the outer periphery of Hurricane Erin, this
could result in a localized zone of very heavy rain during the
overnight hours. No Flood Watch is necessary at this point, but
some of the high-resolution model guidance has some substantial
rainfall amounts, particularly in central/northeast MD.

On Thursday morning, the frontal boundary nearby begins to
accelerate toward the southeast as a cold front. As this occurs,
Hurricane Erin is expected to be a couple hundred miles offshore
of the Outer Banks of North Carolina. Despite its position well
southeast of the Mid-Atlantic region, an uptick in synoptic
winds is likely due to the very expansive wind field that Erin
has amassed at this point. The current forecast calls for high
temperatures in the mid 70s to low 80s, but with northerly gusts
of 15 to 25 mph. While some showers are possible, much of the
day is likely dry with the post- frontal wind shift to
northerly. This cold advection regime will make for a cooler
night on Thursday. Low temperatures are expected to drop into
the upper 50s to mid 60s (mid/upper 50s for mountain locales).

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
High pressure to the northeast will build into the area Friday, and
a shortwave ridge will quickly pass across the area aloft. This
should keep conditions dry, although some residual moisture may
linger across the southwestern part of the CWA as the frontal zone
hangs up along the central and southern Appalachians. The high will
move farther to the east on Saturday, allowing southerly flow to
take over which will warm temperatures back closer to normal (though
likely remaining below 90F for most areas). A potent shortwave
trough will also be digging through the Great Lakes over the
weekend. There is some uncertainty with how much forcing will reach
the area Saturday, but there may be enough height falls along with
increasing moisture and terrain circulations to result in some
showers and thunderstorms mainly west of the Blue Ridge.

While there is some uncertainty still in the timing, the cold front
will approach the area on Sunday. The chance for showers and
thunderstorms will be highest this day as increased dew points pool
ahead of the front. Machine learning models indicate low
probabilities of severe thunderstorms given increasing wind profiles
aloft. Modest instability will be the limiting factor. Some guidance
is slow to move the front eastward Monday, but the highest chance of
rain should be east of the area. If not Monday, then definitely
Monday night and Tuesday will feature the arrival of cooler air and
lower dew points. Highs Tuesday will be in the upper 70s and lower
80s as dew points drop to the 50s if not upper 40s under mostly
sunny skies.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
IFR to LIFR CIGs are likely again tonight owing to persistent
low stratus. There will also likely be drizzle in most of the
same spots, perhaps lasting into the mid- morning hours.

On Wednesday, the frontal zone to the south eventually begins to
move across the area as a warm front. Depending on its location,
a gradual shift to southeasterly winds are expected on
Wednesday. Some restrictions are possible in the morning as low
ceilings continue, but improvement is expected mid-late morning.

Some afternoon showers and thunderstorms may impact the more
western TAF sites. The frontal zone eventually pulls away from
the region late Wednesday into Thursday as a cold front. During
the overnight hours on Wednesday, some heavy rain is possible in
central/northeast MD, so that will be something to watch in
future TAF updates.

In the wake, increasing north- northeasterly winds are likely
with gusts up to 15 to 20 knots, perhaps a bit higher depending
on Hurricane Erin`s influences. A few showers are also possible
on Thursday as the system pulls away.

Tranquil weather is expected Friday under weak high pressure. A
thunderstorm is possible at MRB Saturday afternoon or evening as the
next frontal system begins to approach. This front will cross the
area Sunday with a greater chance of showers and thunderstorms
areawide.

&&

.MARINE...
Small craft advisories for the open waters of the Bay will
linger for another hour or so as northeast winds remain a little
gusty. Winds should start to taper off before midnight as a
mesolow pulls away.

After a temporary reprieve in the winds, another round of gusty
conditions are expected late Wednesday into Thursday. This is in
response to the expanding wind field of Hurricane Erin. Northerly
gusts of 20 to 25 knots are looking likely, with the potential
for Gale/Tropical Storm Force wind gusts, at least briefly,
Thursday afternoon/evening as Erin makes its closest approach.

SCA conditions may continue into Friday for parts of the waters in
northerly flow. High pressure building north of the area will turn
winds to the east Friday night and then to the south Saturday,
likely below advisory levels. Southerly channeling may increase
winds to near advisory criteria by Saturday evening. An approaching
cold front may bring thunderstorms on Sunday as southerly winds
continue.

&&

.TIDES/COASTAL FLOODING...
Tidal anomalies will steadily rise for the next 24 hours as
onshore flow strengthens in response to Hurricane Erin tracking
east of the area. A Coastal Flood Warning remains in effect for
Annapolis, with Coastal Flood Advisories for Solomon`s Island,
Baltimore, and Dahlgren. Additional advisories are likely needed
to account for high tides Wednesday into Wednesday night. The
winds turn northeast then north by Thursday morning, which will
allow water levels to rapidly drop Thursday afternoon into
Friday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory from 3 AM to 9 AM EDT Wednesday for
     MDZ011.
     Coastal Flood Warning until 8 AM EDT Wednesday for MDZ014.
     Coastal Flood Advisory until 4 AM EDT Wednesday for MDZ016.
     Coastal Flood Advisory until 2 PM EDT Wednesday for MDZ018.
VA...Coastal Flood Advisory until 4 AM EDT Wednesday for VAZ057.
WV...None.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ534-
     537-542-543.

&&

$$

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