265
FXUS61 KLWX 041936
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
336 PM EDT Fri Jul 4 2025

.SYNOPSIS...
High pressure will build across the area this holiday weekend,
while low pressure develops off the southeastern U.S. coast. A
cold front will approach from the northwest Monday, before
potentially stalling near the area during the middle to latter
portions of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
Compared to recent Independence Day holidays, it is certainly
much less humid than typical days this time of year. The pattern
aloft features a pronounced longwave trough just off the New
England coast, while ridging prevails across the middle of the
country. Generally sandwiched in between this pair of synoptic
features, a northwesterly flow regime is being observed across
the local area.

Through the column, aircraft soundings near D.C. show mainly
uniform north to northwesterly flow. The dry nature of this air
mass is evident in current precipitable water values which
average close to 0.65 to 0.70 inches. Based on the Storm
Prediction Center sounding climatology, this value runs below
the 10th percentile. The net result is sunny conditions over the
area, although some cumulus development has persisted over the
higher terrain the past few hours. Despite these terrain
circulations aiding in enhanced cumulus fields, the vertical
motions should be stunted by dry air and subsidence aloft.
However, there were enough high-resolution models that showed
some weak development to support isolated afternoon showers in
this forecast package. If these do develop, they should be short
lived and dissipate well before sundown.

For temperatures, the combination of ample sunshine and early
July solar insolation angles have raised temperatures well into
the low/mid 80s. The dry nature of the air mass (dew points in
the 50s to low 60s) should allow readings to approach the mid/upper
80s during the next couple of hours. Heading toward sundown and
when fireworks displays will be underway, most can expect
temperatures in the 70s (60s in the mountains). Light winds and
clear skies overnight will yield a seasonably cool night with
lows in the low/mid 60s, locally near 70 degrees inside D.C. and
Baltimore. Some patchy fog may develop across the Shenandoah
Valley and points westward.

Saturday should provide much of the same to the area as
mid/upper heights gradually build under the expanding ridge.
Plenty of sunshine is again expected with high temperatures
likely to near the 90 degree mark in many spots. However, the
overall temperature forecast is fairly close to early July
climatology. The biggest difference is a wind shift over to
south-southeasterly as surface high pressure exits offshore.
This results in an uptick in humidity levels with dew points
rising into the low/mid 60s. Despite this increase in moisture,
subsidence aloft should squash any shower chances on Saturday.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
The uptick in moisture levels will lead to a gradual increase in
overnight lows. Forecast temperatures on Saturday night are
expected to be in the mid/upper 60s, with a few spotty low 70s
possible. While Sunday morning starts off with mainly clear
skies, high clouds may be on the increase as a disturbance over
the southeastern U.S. begins to lift northward. Such a system is
currently an invest area in the latest National Hurricane
Center forecast. At this point, any shot for showers that graze
the area would be along I-95 in central Virginia eastward into
far southern Maryland. This would mainly be during the late
afternoon to evening hours on Sunday.

Forecast temperatures on Sunday are expected to creep up a bit
further with readings in the upper 80s to low 90s. The influence
of humidity will be evident in its heat indices around the mid
90s. Heading into Sunday night, some residual cloud cover is
likely along and east of I-95. Forecast temperatures overnight
will mainly range from the upper 60s to mid 70s (low/mid 60s
across the mountains).

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The long-term period becomes a bit more active across the region.
There are two features in particular to track on Monday. The first
of which is an approaching frontal boundary dropping southward
towards the region. As the upper-level ridge begins to push east
and break down across our region, this will allow for an increased
chance of thunderstorms once again. This will occur in a fairly hot
and humid airmass, so there could be a few strong to severe storms.
Secondarily, there is the low pressure system currently spinning off
the southeast coast. This will very slowly drift north towards the
region. Per the latest guidance, it seems Monday would be the
earliest that any potential impacts from this system could arrive,
particularly later in the day/evening. Still a lot of uncertainty
here, but at this point it just looks like a potential rain maker,
if it even makes it this far north.

Tuesday through the end of the week will be quite active as several
pieces of shortwave energy move across the region. Hot and humid
conditions ahead of all of these upper-level systems will likely
result in several rounds of thunderstorms. At this point, Thursday
probably looks like the most impactful day, at least given the
current model guidance. This looks to be the strongest system, so
would look to this day as a day to watch. Otherwise, there will be
daily chances for isolated to scattered strong/severe thunderstorms
areawide.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions will be commonplace through the holiday weekend.
A building ridge aloft should limit any shower development to
the Allegheny Front today. Otherwise, the forecast remains dry
through Saturday. Some patchy fog development is possible on
Saturday morning, mainly west of the TAF sites. By Sunday, an
approaching area of disturbed weather lifts northward from the
southeastern U.S. coast. While any impacts should stay well
south of the area, some uptick in cloud cover is possible on
Sunday. Initial northerly winds today will give way to south-
southeasterlies this weekend as high pressure moves off the
coast.

Generally expecting VFR conditions through the long term period.
However, each day will come with an increasing chance of
afternoon/evening thunderstorms. This will bring a chance for
restrictions at any of the terminals.

&&

.MARINE...
Conditions across the marine waters are likely to remain
favorable through much of the holiday weekend. Northerly winds
may gust to around 10 knots or so this afternoon, while winds
eventually shift to south-southeasterly for the weekend. The
flow around high pressure off the Atlantic begins to pick up by
Sunday evening. Small Craft Advisories may be needed for Sunday
evening into Sunday due to southerly channeling effects,
especially over the more southern waters.

Showers and thunderstorms are possible over the waters as a cold
front approaches the forecast area next week. Winds are expected to
stay below SCA criteria both Monday and Tuesday, although SMWs are
possible during afternoon showers and thunderstorms.

&&

.TIDES/COASTAL FLOODING...
Southerly winds will return this weekend, driving slight
increases in water level anomalies. While flooding is unlikely
for most areas, a push of slightly stronger winds could result
in Annapolis nearing the minor threshold early Monday morning.

&&

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

&&

$$

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