023
FXUS61 KLWX 190057
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
857 PM EDT Fri Jul 18 2025

.SYNOPSIS...
A stationary front over the area today will return northward as a
warm front tomorrow. A cold front will move through Sunday night.
High pressure will build to our north early next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of ~01Z, showers are the predominant precipitation type
across the FA. A thunderstorm complex exists over
Fredericksburg, but trend has been steady or slightly down in
terms of growth based on lightning and cloud tops. Additional
heavy rainfall is likely in the Fredericksburg vicinity. Expect
continued showers in spots through the evening, with any
remaining activity winding down by around or shortly after
midnight. Dry conditions are expected during the second half of
the night.

Low clouds may try to develop later tonight, and fog
may form in locations that don`t get the low clouds. Overnight
lows are expected to be in the upper 60s and lower 70s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
The stationary boundary located over the area today will make
slight northward progress as a warm front tomorrow. Flow aloft
will remain primarily zonal. A weak convectively generated
disturbance may approach from the west during peak heating. The
combination of daytime heating and weak ascent associated with
this feature will result in another round of showers and
thunderstorms tomorrow afternoon into tomorrow evening.
Currently it appears as though the highest coverage of these
storms (much like today) will be in the Central Shenandoah
Valley and Central Virginia. However, a brief afternoon or
evening thunderstorm may be possible anywhere in the forecast
area. Storms may be capable of producing isolated to scattered
instances of flooding, as well as a damaging wind gust or two.
High temperatures will be in the mid-upper 80s for most, with
dewpoints holding in the 70s.

Upper troughing will start to dig to our north across Northern
New England on Sunday, while low pressure tracks through the
Canadian Maritimes. This will cause a cold front to drop
southward across NY, New England and PA over the course of the
day. Storms may try to form along a pre-frontal trough Sunday
afternoon. Some of these storms may be strong to severe. SPC
currently has the entire area outlooked in a Marginal Risk for
severe thunderstorms.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Characterized by 500-mb height anomalies running around 1.5 to 2
standard deviations below average, a formidable upper trough is
forecast to continue tracking eastward across the Canadian
Maritimes. This pattern shift allows for a broad dome of Canadian
high pressure that settles over Quebec into New England through mid-
week. On Monday, a steady northerly component to the surface winds
will sufficiently lower dew points over the area. This ultimately
results in a multi-day reprieve from the 2 to 3 weeks of continued
heat and humidity. Although the current forecast package shows dew
points in the upper 50s to mid 60s, plenty of solutions carry
readings into the mid 50s. This is accompanied by daily high
temperatures in the low/mid 80s (upper 60s to 70s in the mountains).
Widespread overnight lows will be in the 60s, with some upper 50s
along the mountain ridges. Any shower chances through Tuesday are
tied to the Potomac Highlands into the central Shenandoah Valley.
Some perturbations circulating clockwise around a ridge across the
Lower Mississippi Valley could invigorate some localized lift.

By Wednesday, some return flow picks up as the surface anticyclone
exits the New England coast. The global ensemble consensus shows
this scenario unfolding which helps increase dew points across the
Mid-Atlantic region. At the same time, a broad upper ridge initially
over the south-central U.S. will expand both north and east in time.
Its influence on the local area is expected to come with rising
daily temperatures, especially by Thursday and Friday. A return of
temperatures in the low/mid 90s is looking more likely, but ensemble
spread does increase as noted by sizeable box-and-whisker plots.
While thunderstorms do not come back immediately, expect a better
chance for such storms by late in the week. This is in response to
some northern stream amplification noted in a number of models.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
Removed any thunder from TAFs this evening. Pretty much SHRA at
this point over the southern terminals. Low clouds may move in
later during the night. IFR ceilings appear possible for a time
later tonight into early tomorrow morning, but gradual
improvement back to VFR ceilings is expected over the course of
the morning tomorrow. Thunderstorms will form again tomorrow
afternoon, with most of the activity focused over central VA.
Confidence is currently too low to introduce PROB30s in the
DC/Baltimore Metro terminals, but at least a PROB30, if not a
TEMPO will eventually be needed for CHO. Additional
thunderstorms may be possible on Sunday afternoon.

With precipitation chances looking pretty low on Monday through
Wednesday, expect VFR conditions at all terminals. The shift in the
pattern ushers in a northerly wind on Monday before turning more
east-southeasterly by Tuesday. Once Canadian high pressure exits the
New England coast on Wednesday, a return southerly flow is
expected.

&&

.MARINE...
Light and variable winds are expected over the waters this
evning. An SMW for thunderstorms may be needed later this
evening, particularly over the middle to lower Tidal Potomac.
Light south to southeasterly winds are expected tomorrow, and
then light westerly winds on Sunday. Winds will shift to out of
the north behind a cold front Sunday night, and potentially
could near low-end SCA levels during that time. SMWs may
potentially be needed for thunderstorms during the afternoon and
evening hours both days this weekend.

Winds across the marine waters should stay below advisory levels
through Tuesday. A northerly wind may gust around 10 to 15 knots on
Monday before shifting to east to northeasterly on Tuesday. There is
no threat for thunderstorms as Canadian high pressure builds to the
north.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Flood Watch until midnight EDT tonight for MDZ016.
VA...Flood Watch until midnight EDT tonight for VAZ025>031-036>040-
     050-051-055>057-501>504-507-508-526-527.
WV...Flood Watch until midnight EDT tonight for WVZ055-501-502-505-
     506.
MARINE...None.

&&

$$

SYNOPSIS...KJP
NEAR TERM...KJP/CPB
SHORT TERM...KJP
LONG TERM...BRO
AVIATION...BRO/KJP/CPB
MARINE...BRO/KJP/CPB