877
FXUS61 KLWX 070801
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
401 AM EDT Tue Oct 7 2025

.SYNOPSIS...
A cold front will approach from the northwest today, before
moving through the area on Wednesday. High pressure will move in
for Thursday and Friday. A coastal low will develop to our south
this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure continues to circulate offshore this morning.
Further off to the northwest, a potent upper trough is tracking
across Ontario toward Lake Superior. A corresponding surface
cold front extends from the Central Great Lakes southwestward
toward the Southern Plains, with high pressure building in its
wake over the Central and Northern Plains.

High pressure will remain in place offshore through the day
today. Light southerly flow to the west of the high has helped
to keep temperatures up and limit fog formation compared to
previous nights, despite the clear skies and higher dewpoints in
place. Winds will gradually increase out of the south through
the day today, eventually gusting to around 15 to 25 mph this
afternoon. Clouds will also be on the increase through the day.
The clouds should move in this morning to the west of the Blue
Ridge, and then during the early afternoon hours further east.
Temperatures will be well above normal once again, with highs in
the upper 70s and lower 80s for most. It will also be a touch
humid, with dewpoints climbing into the lower 60s.

As large scale ascent ahead of the approaching upper trough
starts to overspread the area, showers will gradually move in
from northwest to southeast. Most, if not all of the forecast
area should remain dry this morning, but showers should move
into the Alleghenies early this afternoon. These showers should
reach the I-81 corridor during the mid-late afternoon hours, and
then spread to the east of the Blue Ridge later this evening
into the overnight. Showers will continue on and off for all of
the area through the overnight hours.

Some models show weak surface based instability developing this
afternoon to the west of the Blue Ridge, and then some weak
elevated instability developing across the entire area
overnight. A few embedded thunderstorms may be possible as a
result, but coverage of the storms isn`t expected to be high.
The best chance for a brief thunderstorm will likely be this
afternoon to the west of the Blue Ridge.

Rainfall with this system should be beneficial in nature given
the ongoing drought conditions across the area. Most solutions
have less than an inch of rain across the majority of the area.
However, some CAMs do show isolated totals of 1-2 inches,
especially in the vicinity of Martinsburg and Hagerstown, where
some of the CAMs try to produce thunderstorms this afternoon.
Temperatures will remain mild overnight, with lows in the upper
50s to mid 60s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The aforementioned system`s cold front will move through the
area from northwest to southeast tomorrow morning. Rain will
come to an end and winds will abruptly shift to out of the
northwest behind the front. This will be a powerful
front, causing temperatures to fall during peak heating hours
from daytime highs in the 70s during the morning, to the 60s
during the afternoon hours. Strong dry advection will also ensue
behind the front, causing skies to clear out and sunny skies to
return before the end of the day. Winds will gust to around 20
mph out of the northwest behind the front.

A strong area of high pressure will build to our north behind
the front. Strong cold advection will transport the coolest
airmass of the season into the region from the north.
Temperatures should drop back into the low to mid 40s for most
Thursday night, purely on advection. A few locations in the
Alleghenies, Potomac Highlands, and Central Shenandoah Valley
may be able to decouple and radiationally cool into the mid-
upper 30s. Patchy frost may be possible in those locations late
Wednesday night.

Sunny skies and cool temperatures are expected on Thursday as
high pressure builds to our north. High temperatures will be in
the low to mid 60s for most, with 50s in the mountains. High
pressure will become centered just to our north across NY/PA
Thursday night, with surface ridging extending down the spine of
the Appalachians. This surface ridge should weaken the pressure
gradient enough for most locations to decouple. The combination
of clear skies and calm winds will allow for ideal radiational
cooling conditions within what will already be an ambiently
cool airmass. As a result, temperatures will drop to their
coolest values of the season. Most locations to the northwest
of I-95 are expected to drop into the 30s, with low to mid 40s
along/southeast of I-95. Higher mountain valleys in the
Alleghenies may even experience a hard freeze. Frost/freeze
headlines will likely be needed for much of the forecast area
Thursday night.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
During the extended period, the synoptic pattern will remain highly
amplified across the country. The features of interest include a
western U.S. trough, strong ridge across the Southern Plains, and
split flow across the Eastern Seaboard. For this area consisting of
a split jet, the area of concern is tied to a developing closed low
in the vicinity of the southeastern U.S. How this upper low evolves
between Friday and Sunday is quite uncertain as suggested by the
large spread in deterministic guidance. Ensemble low cluster plots
are highly confident in surface low development, but with
uncertainty in the strength and position of this cyclone. This
appears to remain a threat through Monday to the area spanning the
Mid-Atlantic coast down to the Carolinas. Continue to check back at
weather.gov/lwx for the latest forecast information.

With a seasonably strong area of Canadian high pressure to the
north, below average temperatures will persist through the weekend.
Daily highs will be in the 60s, with 50s across mountain locales.
While some weakening of this anticyclone is possible, an onshore
gradient is likely to remain with the mentioned low pressure to the
south near the southeastern U.S. The resultant onshore flow will
favor more clouds than sun, especially east of the Blue Ridge. For
those to the west, there should be a better shot for some periods of
sunshine. As mentioned, there are a myriad of solutions at hand in
terms of rainfall chances and amounts. For now, the guidance remains
on the conservative side with 20 to 30 percent chances for rain east
of the Blue Ridge.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
VFR conditions are expected today as winds gradually pick up out
of the south. Winds may gust to around 20 knots this afternoon.
Showers will gradually move in from northwest to southeast as a
cold front approaches the area. These showers should reach MRB
later this afternoon and the rest of the terminals later this
evening. A stray thunderstorm can`t be ruled out either, but
chances were only great enough to mention in a PROB30 at MRB
this afternoon. Lower ceilings will also move in late tonight,
with IFR/MVFR ceilings likely.

A strong cold front will move through the area tomorrow
morning. Showers will come to an end, conditions will return to
VFR, and winds will abruptly shift to out of the northwest
behind the front. Winds will likely gust to around 20 knots for
much of the day tomorrow. Winds will shift to out of the north
Wednesday night, and then to out of the northeast on Thursday
with continued VFR conditions.

Canadian high pressure remains in charge on Friday which will favor
VFR conditions. As low pressure develops off the southeastern U.S.
coast, an increase in clouds and shower chances emerge on Saturday.
Depending on how these clouds/showers enter the forecast, some
restrictions are possible on Saturday. Initial winds will be out of
the north before shifting to mainly easterly by Saturday.

&&

.MARINE...
Low-end SCA gusts will remain possible across the main channel
of the bay this morning within southerly flow. SCA gusts appear
likely for all of the waters this afternoon in southerly flow.
The SCA conditions will continue through the night for
Chesapeake Bay and the Lower Tidal Potomac. Winds will shift to
out of the northwest behind a cold front during the day
tomorrow. SCA gusts appear likely tomorrow afternoon behind the
front. These SCA-level gusts could potentially linger into the
day Thursday.

Canadian high pressure to the north will maintain onshore gradients
on Friday and Saturday. Winds should generally meander between
northeasterly and easterly. Some strengthening is likely on Saturday
as low pressure approaches from the southeastern U.S. coast. Small
Craft Advisories are looking likely on Saturday with gusts up to 20
to 25 knots.

&&

.TIDES/COASTAL FLOODING...
Anomalies are expected to hold relatively steady over the next few
days within southerly flow, before decreasing behind a cold front in
northwesterly flow on Wednesday. Several sites may potentially reach
into Action stage around the time of high tide Tuesday, but no
flooding is expected. Anomalies look to climb later this week
and into the upcoming weekend as onshore flow increase with low
pressure moving north along the coast from the southeast U.S.
Additional coastal flooding threats are possible during this
time, although details are yet to be determined due to
uncertainty regarding the track and placement of the
approaching low.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory until 6 AM EDT Wednesday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ530>534-
     539>541.
     Small Craft Advisory from noon today to 6 PM EDT this evening
     for ANZ535-536.
     Small Craft Advisory from noon today to 6 AM EDT Wednesday for
     ANZ537-538-542-543.

&&

$$

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