968
FXUS61 KLWX 020759
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 AM EDT Tue Sep 2 2025

.SYNOPSIS...
Surface high pressure centered to the north slowly drifts eastward
through midweek. A cold front will reach the area Thursday. A
second, stronger cold front will cross the area Saturday. High
pressure will build in from the northwest early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface high pressure is centered closer to New England this
morning, while the upper level low has drifted close to Lake
Ontario. Very little fog has developed so far, hindered in some
areas by patches of mid level clouds. However, some patchy fog
could occur in some of the river valleys through sunrise where
it is clear.

The upper low will begin to fill today while a shortwave trough
rotates across the Mid Atlantic. Overall the dry airmass should
limit lift to cumulus development for most areas. However, some
isolated showers may form over the higher terrain where
moisture is a bit deeper and there is the added orographic
lift. Guidance also has a secondary signal for a few showers
along the Chesapeake Bay. Have kept this out of the forecast for
now, but if something were to develop, it might be more along
the eastern shore where easterly winds converge with the bay
breeze. Not much change to temperatures today, with highs in the
mid 70s to near 80 (60s in the higher elevations).

Mostly clear skies and light winds will prevail again tonight.
Guidance has mixed signals on fog development, but at least some
patchy coverage is plausible as dew point continue to tick up.
Lows will mostly be in the 50s to near 60, but some outlying
areas, especially in the mountains, could drop into the 40s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
The surface high will stretch along the eastern seaboard
Wednesday, resulting in a shift to southerly winds. Another
shortwave trough will approach from the Tennessee Valley,
although the bulk of this lift may remain southwest of the area.
A few showers and thunderstorms are possible in the afternoon
and evening mainly west of I-81, where moisture advection will
be a bit more pronounced. Daytime highs increase a bit into the
upper 70s and lower 80s. Most of Wednesday night should remain
dry with lows in the mid 50s to lower 60s.

Low pressure will be lifting north of the Great Lakes Thursday
ahead of a potent upper low. A trailing cold front will approach
the Appalachians during the afternoon. While instability will be
modest, it will be compensated by stronger shear, which may
organize convection ahead of the front into a squall line. While
the severe weather threat is still somewhat uncertain, any more
organized segments could carry a damaging wind threat. SPC has
highlighted areas near and west of the Blue Ridge in a Marginal
Risk. Activity may tend to weaken or even fall apart as it moves
eastward due to several factors: a more stable airmass east of
the Blue Ridge, loss of diurnal heating, and mid level support
pivoting off to the north. Any lingering shower risk should end
overnight. The cold front will be in a weakening state as it
reaches the area overnight. Gusty southerly winds help highs
reach the lower to mid 80s on Thursday. Overnight lows will be
in the upper 50s to mid 60s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Height rises Fri into Sat will provide for a brief warmup to the end
of the week before amplifying upper level trough across the
western Great Lks into the Midwest and Ohio Valley pushes a
strong cold front through the area Saturday night. Some timing
differences show up among the global models, however. Showers
will be possible Friday in the warm humid air mass, but are more
likely during the day Saturday. A cool air mass more typical of
late September will establish over the region to start the
second week of September.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Have removed the fog mention for MRB and CHO this morning as
conditions have trended less favorable. Patchy mid level clouds
are across the area and these should expand into a cumulus field
with daytime heating. An isolated shower could develop near MRB
today, but the low coverage and light nature of any such
activity precludes a TAF mention. Northeast winds should remain
less than 10 kt. There are mixed signals for fog and/or low
clouds for tonight, so will keep those out of the forecast for
now.

High pressure continues to provide VFR conditions Wednesday and
Wednesday night, although winds shift to southerly. Any sparse
convective activity likely remains west of MRB and CHO
Wednesday. A cold front will approach Thursday, and southerly
winds ahead of it may gust to 20 kt. A line of showers and
thunderstorms will likely approach from the west during the
afternoon or early evening. MRB has the highest chance of
thunderstorms, which could be gusty. The line may tend to weaken
or break up as it moves east of the Blue Ridge during the
evening.

Minimal risk for significant weather Friday. Scattered showers
and thunderstorms are possible Saturday.

&&

.MARINE...
Northeasterly winds prevail today. There may be a brief uptick
along the bay around sunrise, but any gusts that near advisory
levels should be short lived. Winds switch to southerly on
Wednesday as high pressure moves off the east coast. While
southerly channeling may impact the bay Wednesday night, the
chance for advisories seems to have trended down a bit. That
won`t be the case Thursday and Thursday night as flow increases
ahead of a cold front. Advisories will likely be needed for all
waters. Some gusty thunderstorms could reach the waters during
the evening, but current trends suggest they will be in a
weakening state.

SCA conditions are likely Friday through Sunday.

&&

.TIDES/COASTAL FLOODING...
Water levels hold somewhat steady through tonight as northeast
winds remain in place. Annapolis will likely be the only
location that approaches minor flood stage tonight. A flip to
southerly flow Wednesday should allow for further rises in water
levels. Confidence in Annapolis reaching minor flood increases
Wednesday night. Peak water anomalies appear to occur Thursday
night ahead of a front in strong southerly flow. More locations
may reach minor flood, and some guidance has Annapolis
approaching moderate flood. Water levels should decrease
somewhat Friday as the front passes.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

$$

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