751
FXUS61 KLWX 081839
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
239 PM EDT Tue Sep 8 2026

.WHAT HAS CHANGED...
Added a slight chance of showers Wednesday over portions of the
Shenandoah Valley and eastern West Virginia panhandle.

&&

.KEY MESSAGES...
- 1) Mostly dry through mid week.

- 2) Shower and thunderstorm chances return Thursday.

- 3) Cooler and less humid conditions are expected on Friday,
  before humidity builds back in this weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Mostly dry through mid week.

Conditions will remain tranquil as high pressure persists over
the Mid-Atlantic through Wednesday before gradually moving
offshore. Large scale subsidence and dry air lead to a mostly
precipitation-free forecast with temperatures rising to several
degrees above normal as the high pulls offshore.

A weak surface trough in the wake of gradually departing high
pressure may be enough to produce a few showers mainly over the
Shenandoah Valley/I-81 corridor into the eastern WV panhandle
from late Wednesday morning through late Wednesday afternoon.

High temperatures may approach 90 Wednesday (slightly cooler in
the mountains). Low temperatures (and dew points) will be in
the 50s and 60s during this time. Some river valley fog is
likely each morning.


KEY MESSAGE 2...Shower and thunderstorm chances return Thursday.

The upper-level ridge will begin to flatten out Wednesday before
breaking down and pushing south and east into Thursday. Several
pieces of upper-level energy rotating around an upper low
centered over Hudson Bay will slowly push a cold front south
towards our region by Thursday. At the surface, high pressure
pushing offshore will bring increasing warmth and moisture
to the area, with highs in the 80s to near 90 especially south
of US-50/I-66 with dew points in the upper 60s to low 70s. Mid-
level moisture will be increasing on westerly flow, but that
introduces a downsloping component in the lower levels. This
reduces the amount of CAPE/DCAPE, especially when given
anticipated cloud cover over the northern half of the area, for
any potential severe weather. Still, a few clusters particularly
from central VA to southern MD could contain gusty winds and
heavy downpours Thursday, mainly in the afternoon and evening.


KEY MESSAGE 3...Cooler and less humid conditions are expected
on Friday, before humidity builds back in this weekend.

High pressure will build to our north on Friday in the wake of
Thursday`s frontal passage. Cooler and drier air will advect into
the region from the north in advance of the approaching high.
Partly to mostly sunny skies are expected, with high temperatures
in the upper 70s and lower 80s. It will also feel considerably
less humid, with dewpoints dropping into the upper 50s and lower
60s. Some shower or thunderstorm activity is possible near and
south of I-64 as the front stalls just off to the south.

High pressure will move offshore and a strong area of low pressure
will track across Hudson Bay on Saturday, causing winds to turn out
of the south in response. Southerly winds will advect a more humid
airmass back into the area, with dewpoints climbing into the upper
60s and lower 70s. Chances for showers and thunderstorms will
accompany the more humid airmass. Both instability and shear values
are forecast to remain relatively modest, so any storms that do
form likely stay on the weaker side.

There is still some model divergence for Sunday. What we do know is
that the humidity will stick around, bringing chances for showers
and thunderstorms. However, there is still some uncertainty as to
whether or not the marine layer will mix out. If not, temperatures
will be cooler with plenty of clouds. If so, there will be some
breaks of sunshine and it will be warmer. Guidance leans slightly
toward the second scenario, but this will have to be monitored as it
gets closer.

High pressure may return behind a weak cold front for Monday and
Tuesday, bringing drier conditions, but temperatures will most
likely still be above climo.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
VFR conditions are expected to prevail through the end of the
week, with two exceptions. Early morning river valley fog could
affect mainly KCHO/KMRB each day roughly 08z-13z (confidence too
low to include in TAF as of 18Z). Then, some shower and t-storm
activity could bring brief restrictions on Thursday (mainly in
the afternoon and/or evening). Winds remain S/SW through
Thursday until a cold front brings a shift to W/NW.

Low clouds are possible late Friday night into Saturday with
sub-VFR conditions. Showers are possible Saturday along with a
possible afternoon thunderstorm.

&&

.MARINE...
Winds may increase in modest channeling tonight over the lower
tidal Potomac River and the main channel of the Chesapeake Bay,
but are more likely to increase Wednesday afternoon into
Wednesday night. Winds shift to the west and northwest and could
remain gusty Thursday as a cold front crosses, possibly
bringing a few showers and thunderstorms.

Sub-SCA level north to northwesterly winds are most likely over the
waters on Friday. Winds will shift to the south on Saturday, and
could near low-end SCA levels within channeled southerly flow
Saturday afternoon into Saturday evening.

&&

.TIDES/COASTAL FLOODING...
Tide levels remain around 1 to 1.25 feet above normal. Light
flow may allow anomalies to drop slightly to around 1 foot
above astronomical norms through the middle of the week.
Annapolis could reach Minor Stage one or two more times through
Thursday prior to a cold front shifting winds to the west. Other
sites could approach minor flood at times, as well, mainly late
Wednesday night into early Thursday morning, though west-of-
south flow by this time lowers confidence.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 1 PM Wednesday to 7 AM EDT Thursday
     for ANZ530>533-538>542.
     Small Craft Advisory from 4 PM Wednesday to 10 AM EDT Thursday
     for ANZ534-537-543.
     Small Craft Advisory from 4 PM Wednesday to 4 AM EDT Thursday
     for ANZ535-536.

&&

$$

DISCUSSION...BRO/KLW/CJL/KJP
AVIATION...KLW/CJL/KJP
MARINE...KLW/CJL/KJP