785
FXUS61 KLWX 240032
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
832 PM EDT Sat Aug 23 2025

.SYNOPSIS...
Shower chances increase through tonight west of the Blue Ridge
Mountains as a cold front approaches. Shower and thunderstorm
chances continue as the cold front crosses the area Sunday into
Monday. A strong dome of Canadian high pressure builds thereafter
with near to below normal temperatures for much of next week.

&&

.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
KLWX radar loop as of 8:15PM shows showers and thunderstorms
approaching the forecast area from eastern West Virginia with
light rain showers over western Maryland. These showers and
thunderstorms are expected to move through the western portions
of the forecast area this evening into the overnight, and are
forecast to remain below severe thunderstorm criteria. However,
gusty winds and heavy rainfall are possible within
thunderstorms. East of the Blue Ridge, dry conditions are
expected. The 00Z KIAD sounding showed plenty of dry air aloft
with mid level RH values of around 45%. No changes were made to
the forecast with the previous forecast discussion below.

Weak high pressure dominates the weather over the Mid-Atlantic
as it drifts offshore through tonight. Subtle convergence near
and immediately in the lee of the Appalachians may result in a
few showers or a thunderstorm into this evening, but dry weather
is expected elsewhere due to subsidence and nil forcing.

Humidity will trend up through tonight on south to southeast
winds. This will hold low temperatures in the 60s for most.

&&

.SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
An upper low over southern Ontario on Sunday will dig across the
Great Lakes and northern Mid-Atlantic early next week pushing a
strong cold front through the area Sunday. Showers and
thunderstorms are expected Sunday into Sunday night before the
cold front moves eastward. SPC maintains general thunder for
Sunday with no categorical outlook. Cannot rule out a SVR storm
or two, but there is a disconnect between moisture, instability,
and forcing. Scattered storms should remain progressive limiting
any flood threat, although a few mergers are possible with
locally higher totals from the north-central Shenandoah Valley
into the central Virginia piedmont.

The cold front will exit the area early Monday after 06Z with
showers ending shortly thereafter. Expect a slight bump in
winds Monday as the front exits east and high pressure builds
from the Ohio River Valley. Gusts of 15 to 20 mph are possible
out of the north and northwest. Temps Monday will be below
average with 70s to near 80 for most. Areas AOA 3.5kft in the
Alleghenies likely don`t make it out of the 50s Monday - a sign
of what is to come later this week with a true Autumnal airmass
setting in. Lows Monday night in the 50s for most (60s along
water and city centers). High elevation valleys and bogs likely
see the first frost of the fall.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A broad upper-level trough will dominate the East all of next
week with reinforcing shortwave troughs moving across. At the
surface, Canadian high pressure will build from the mid-Missouri
River Valley Tue to the Mid-Atlantic by Thu morning keeping a
cool and dry air mass in place. Weak moisture return is possible
by the end of next week, but overall any precip chances look
pretty low. It will be cooler than normal, especially at night.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions will continue through tonight as high pressure
pushes east of the region. Winds will remain out of the south
to southeast.

Prevailing VFR conditions are expected on Sunday and Monday,
although temporary drops to sub-VFR may be possible on Sunday
afternoon as scattered thunderstorms move through. Winds will be
out of the south on Sunday, and then out of the west to
northwest on Monday. VFR conditions are expected thereafter for
much of next week (Tuesday through Friday) as Canadian high
pressure settles over the region. No sig weather expected
Tuesday through Wednesday.

&&

.MARINE...
High pressure will continue to weaken while shifting offshore
through tonight. This will allow channeling to occur. Southerly
winds will gust to around 15 to 20 kts through this evening. A
Small Craft Advisory remains in effect to account for this.

Sub-SCA level winds are expected on Sunday outside of marginal
southerly channeling in the early evening, and may approach SCA
levels mainly Monday night as winds turn northwest behind a cold
front. SMWs may potentially be needed as thunderstorms pass
over the waters Sunday afternoon into Sunday evening.

No marine hazards Tuesday through Wednesday night. Winds northwest
10 to 15 knots Tuesday through Wednesday night.

&&

.TIDES/COASTAL FLOODING...
The worst of the coastal flooding has already occurred, but
water levels will be slow to recede due to southerly channeling
and until a cold front clears the area Monday and winds shift to
the NW. Expect one more cycle of moderate coastal flooding at
Annapolis early Sunday due to high astronomical tides.
Otherwise, widespread minor coastal flooding will continue
through early Monday.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until 6 AM EDT Monday for MDZ011-018-
     508.
     Coastal Flood Warning until 10 AM EDT Sunday for MDZ014.
     Coastal Flood Advisory until 7 PM EDT Sunday for MDZ016.
     Coastal Flood Advisory until 8 PM EDT Sunday for MDZ017.
VA...Coastal Flood Advisory until 7 PM EDT Sunday for VAZ054-057.
WV...None.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ531>534-
     536>543.

&&

$$

SYNOPSIS...DHOF/CPB
NEAR TERM...AVS/DHOF/CPB
SHORT TERM...DHOF/CPB
LONG TERM...LFR
AVIATION...LFR/DHOF/CPB
MARINE...LFR/DHOF/CPB/EST
TIDES/COASTAL FLOODING...LWX