950
FXUS61 KLWX 311915
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
315 PM EDT Sun Aug 31 2025

.SYNOPSIS...
High pressure will slowly drift north and northeast of the area
through Wednesday. A pair of cold fronts will cross the area
Thursday into Friday. High pressure gradually builds in from the
west sometime next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
To finish out meteorological summer (June 1-August 31), a fairly
persistent pattern has brought continued tranquil weather to the
region. The pattern aloft features broad anomalous troughing
across the Canadian Maritimes down over the eastern U.S. While
the stronger forcing is moving toward Newfoundland, a separate
closed low is gradually developing over the Mid-Atlantic region.
Looking down at the surface, an expansive 1028-dm anticyclone
remains centered over the Great Lakes region.

While the forming upper/closed low is spawning some fair weather
cumulus over the area mountain ranges, the lack of moisture is
the true limiting factor for any shower development. Any
updrafts showing up on radar remain west of the Allegheny
ridges and out of the forecast area. However, given some modest
cumulus development over far western portions of Highland and
Pendleton counties, will maintain isolated afternoon showers in
the forecast.

For late August standards, the current air mass is quite dry,
generally running below the 10th percentile (12Z precipitable
water value was 0.63 inches). With daytime heating/boundary
layer mixing, temperatures have steadily warmed in the sub-
saturated environment. Some hinderance in daytime heating may
be taking place east of I-95 into southern Maryland where a
thicker cirrus shield is tracking overhead. Residing along the
leading edge of a weak jet maxima, such high clouds are likely
restricting some sunshine. Therefore, expect temperatures to
stay closer to the mid 70s in these locations. Elsewhere, ample
solar insolation should carry highs into the upper 70s to near
80 degrees later this afternoon (mid 60s to low 70s across
mountain locations).

Light northerly winds will turn more east-northeasterly today
before going calm overnight. Strong ridging at the surface
combined with light winds and mostly clear skies should support
adequate nocturnal radiational cooling. With guidance not
handling this pattern of late, have maintained the trend of
lowering temperatures a bit. This favors overnight lows in the
upper 40s to low 50s (mid/upper 50s closer to the I-95
corridor). While uncertain, some patchy river and mountain
valley fog are possible, mainly after 2 AM and west of the Blue
Ridge.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The quasi-stationary upper low remains nearby on Labor Day
before lifting poleward into Tuesday. With this system overhead,
this will likely introduce a more extensive fair weather cumulus
field. Moisture does remain quite scant as any appreciable
moisture is tied to an inverted trough off the Carolina coast
and down into Florida. Despite the uptick in cumulus
development, this does not really hinder diurnal heating.
Forecast high temperatures should again rise into the upper 70s
to perhaps even low 80s in a few spots. General onshore
gradients also continue as high pressure bridges the area to the
north. The clockwise circulation about this ridge will favor a
northeasterly wind through the day which should also raise the
dew points (40s back into the low 50s).

High pressure remains to the north but weakens in time. Another
chilly night lies ahead, but with temperatures a tad milder as
lows fall into the low/mid 50s. The I-95 metro hubs should be
closer to 60 degrees, while mid/upper 40s are more commonplace
in the mountains.

As the initial upper low lifts into southern Quebec, trailing
cyclonic flow persists east of the Mississippi River Valley.
With an uptick in moisture levels and lift from the longwave
trough, expect additional cloud cover over the area. However, a
persistence forecast continues with little to no change in the
daily box-and-whisker plots. Thus, it will be another day around
80 degrees with mountain highs in the 60s to low 70s. Winds
shift to southeasterly as high pressure further weakens. This
introduces more maritime effects and thus a slightly milder
night than previous ones. Forecast lows are in the mid 50s to
low 60s, with lows 50s in the mountains.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Surface high pressure shifts offshore over the Atlantic Wednesday
with winds shifting southerly and 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. Severe chances appear
limited at this time with ideal shear parameters lagging behind the
frontal passage timing. That being said, showers and thunderstorms
are expected to develop ahead of the cold front. Precipitation
chances decrease, but linger on Friday as the cold front remains
nearby. Surface high pressure builds in from the west Friday
afternoon and Saturday with dry conditions expected.

High temperatures each day will be in the 70s to low 80s with higher
elevations staying in the 60s. The exception will be on Friday, when
temperatures will be slightly cooler in the wake of the cold front.
Expect high temperatures in the 60s to 70s.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A very persistent weather pattern continues over the region.
Thus, expect dry weather and VFR conditions to largely rule the
period through at least Tuesday night. Any patchy fog that
develops is expected to remain west of the TAF sites. However,
would not be surprised to see brief overnight restrictions at
KMRB or KCHO given these areas are more fog prone.

Initial winds this morning were northerly but have since shifted
to northeasterly. Given the light nature of the winds, some
minor shifts are possible at any time. High pressure gradually
weakens into the new work week as winds turn more easterly on
Monday. A few afternoon gusts up to 10 to 15 knots are possible.
Winds eventually turn more southeasterly by Tuesday as high
pressure moves overhead.

South winds are expected on Wednesday, blowing 5 to 10 knots across
all terminals. Winds remain out of the south on Tuesday, gusting 15
to 20 knots in the afternoon. Sub-VFR conditions are possible on
Wednesday and Thursday as a cold front approaches and moves through
the terminals. Showers and thunderstorms are possible ahead of the
cold front Thursday afternoon.

&&

.MARINE...
Due northerly flow has resulted in some channeling effects over
the more open waters today. However, wind observations largely
have shown gusts to around 15 knots. Would not be surprised by a
few additional upticks given the deeply mixed nature of the
boundary layer. Northeasterly winds pick up again overnight
with Small Craft Advisories in effect across the southern waters
from 4 AM until noon on Monday. Gusts up to 20 knots are
expected during this time. Such advisories may need to be
extended into Monday afternoon as well.

Winds move below advisory levels on Tuesday as high pressure
weakens overhead.

Small Craft Advisories are possible Wednesday and Thursday as south
winds channel up the Chesapeake Bay. The greatest chance for SCA
criteria winds will be Thursday afternoon, when winds around 20
knots across the central portions of the Chesapeake Bay.

&&

.TIDES/COASTAL FLOODING...
Light winds have resulted in increased water levels sloshing
back up the bay. However, no flooding is forecast through Monday
morning. The combination of low pressure passing offshore and
easterly winds will allow water to build by Monday evening.
Should the higher water remain suppressed through Tuesday, a
flip to southerly flow Tuesday night into Wednesday should allow
for further rises. At some point, these increased anomalies 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...Small Craft Advisory from 4 AM to noon EDT Monday for ANZ534-
     537-543.

&&

$$

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