420
FXUS61 KLWX 310113 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
913 PM EDT Sat Aug 30 2025

.SYNOPSIS...
High pressure will slowly drift north and northeast of the area
through the middle of the week. An upper-level disturbance may
bring a few showers to the Potomac Highlands Sunday, but most of
the area will remain dry with below normal temperatures through
Wednesday. The next frontal system may bring higher rain
chances toward the end of the week. Cooler tempeatures are
likely in the wake of this front.

&&

.NEAR TERM /THROUGH SUNDAY/...

High pressure will build into the region through Labor Day
keeping a quiet weather pattern. Under ideal radiational cooling
conditions, lows Sunday morning will be similar to this
morning`s in the low 50s away from the cities and 40s in the
mountains.

Previous afd...

Anomalous troughing anchoring much of northeastern North America
has largely maintained an autumnal like air mass over the area.
Characterized by mid-level height anomalies around 2 standard
deviations below average, the core of lower heights extend from
southeastern Quebec and points southward.

A strong anticyclone currently across the Ohio Valley and Great
Lakes will approach from the west this evening into the
overnight hours. This eventually sets up an optimal period for
nocturnal radiational cooling. Models have recently been
underdoing the amount of cooling within these favorable
conditions. Consequently, have favored the colder solutions
which supports overnight lows in the low/mid 50s (mid/upper 40s
across the higher terrain). Relative to late August climatology,
this is around 10 degrees below average. Skies should remain
clear overnight along with calm winds. Some patchy fog
development is possible across the more sheltered river and
mountain valleys.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
Benign weather prevails through the remainder of the holiday
weekend. As a brunt of the upper trough translates offshore into
the Canadian Maritimes, additional longwave energy begins to
close off over the Mid-Atlantic region. While mainly centered
over the local area, this closed low configuration begins to
extend back toward the Upper Great Lakes. However, this does not
contribute to any meaningful shower chances given a dearth of
moisture. A brief uptick across the Potomac Highlands could
introduce a short lived shower, but this would be the exception
more than the rule. Otherwise, modified Canadian high pressure
remains in charge with the primary moisture axis tied to an
inverted trough near the Carolinas.

Forecast highs generally remain on repeat given the fairly
persistent pattern. The current package calls for high
temperatures in the upper 70s to near 80 degrees (60s to low 70s
for mountain locales). Surface high pressure gradually weakens
in time, but this will still support seasonably cool overnight
temperatures. Forecast lows fall into the 50s, with mid/upper
40s in the mountains.

Overall wind fields generally stay out of the east to northeast
through the second half of the Labor Day holiday weekend. Some
minor shifts are possible at times as the anticyclone shifts its
position. However, weak pressure gradients will keep gusts
mainly at 10 mph or less.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Surface high pressure shifts offshore over the Atlantic Tuesday and
Wednesday. Winds shift southerly on Wednesday, ushering in warm and
moist air. This will result in increased moisture, cloud cover, and
gradually warming temps. Precipitation chances increase beginning
Wednesday afternoon from west to east as a cold front approaches
from the Great Lakes region. Precipitation chances increase on
Thursday as the front pushes through the forecast area. Given high
temperatures in the 80s, instability will be limited although
isolated thunderstorms cannot be ruled out. In the wake of the cold
front, surface high pressure returns on Friday.

High temperatures Tuesday through Thursday will be in the 70s to low
80s with higher elevations staying in the 60s. On Friday,
temperatures will be slightly cooler in the wake of the cold front.
Expect high temperatures in the 60s to 70s.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
With the dominance of surface high pressure over the region, VFR
conditions are looking likely through the remainder of the
holiday weekend. Some patchy fog is possible, but this should
stay west of all TAF sites. As high pressure shifts position in
time, expected winds on Sunday and Monday will turn more
northeast to easterly.

VFR conditions are expected Tuesday and Wednesday as high pressure
shifts offshore. Cloud cover increases on Wednesday, with VFR
conditions expected both days. Northeast winds on Tuesday shift to
southerly Wednesday, blowing 5 to 10 knots each day.

&&

.MARINE...
In the wake of yesterday`s frontal passage, any gusty winds have
finally abated. Winds turn more east to northeasterly for
Sunday and Monday with gusts staying below advisory criteria.

Northeast winds on Tuesday shift to southerly Wednesday. Winds
remain below SCA criteria on Tuesday before increasing to just under
SCA criteria on Wednesday. Advisories may be needed in the central
portions of the Chesapeake Bay Wednesday afternoon.

&&

.TIDES/COASTAL FLOODING...
A surge of northerly winds have resulted in decreasing
anomalies today, generally averaging between -0.25 to 0.25
feet. As winds slacken this evening, some of the water may slosh
back up the bay, but flooding is not expected. The combination
of low pressure passing offshore and easterly winds will allow
water to build starting Monday. Winds then remain easterly then
southerly through at least Thursday. This could result in some
minor flooding during the higher high tides along sensitive
shoreline (such as Annapolis).

&&

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

&&

$$

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