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316
FXUS61 KLWX 100839 CCA
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
404 AM EDT Thu Jul 10 2025

.SYNOPSIS...
A weak front will remain across the area through Friday. Weak
high pressure will build over the area Saturday, then another
front may drop southward toward the area Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
A weak surface front/pressure trough extends northeast to
southwest across the area. Aloft, a trough axis extends
southward from the Great Lakes along the western Appalachians.
Moisture and lift in deep southwest flow ahead of trough has
resulted in some scattered showers developing through the night,
although the coverage has started to diminish over the last hour
or so. Low clouds are becoming more common across the area and
may take some time to scatter/lift today. Some patchy fog is
also developing, but thick mid and high levels should prevent it
from becoming too widespread.

There is some uncertainty with coverage of showers through the
morning, as a few models show fairly extensive coverage of light
rain developing, while a larger number just have a few
scattered showers, mainly south and east of DC. This could have
some effect on heating, although with moist southwest flow
remaining in place, few breaks in the clouds will likely occur
until afternoon, generally progressing from southwest to northeast.
With the cloud cover and temperatures only rising into the lower to
mid 80s, instability will be much less than previous days. The
fact that the trough axis will be moving overhead in the moist
environment likely mean that at least some scattered showers and
storms will develop, but severe weather looks unlikely. The
greatest coverage will likely be along the southern and western
periphery of the CWA where there will be more sun. Precipitable
water values will be around 1.5-1.8 inches west of the Blue
Ridge and closer to 2 inches to the east, so there is still some
threat of heavy rain due to slower storm motions. However, due
to the lower coverage and lower instability in place, the
flooding threat should be more isolated today. If there is one
area to key in on, it would be Nelson and Albemarle, where
greater storm potential intersects saturated ground. Will
continue to monitor the need to coordinate a watch in this area.

With the trough axis and deeper moisture progressing to the east
tonight, rain chances should quickly decrease and there may be
some clearing. There`s a signal in guidance for fog to develop,
and some could be locally dense. Lows will be in the mid 60s to
lower 70s.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Subtle ridging will begin to build Friday, and the surface
front/trough will become increasingly diffuse. More sunshine
will allow temperatures to bump upward into the mid 80s to lower
90s. Without a strong trigger, convective development will
likely be tied to the terrain, though scattered activity could
form elsewhere, especially closer to the river/bay breezes.
Low shear will limit the severe threat, though moderate
instability and some drying aloft may support a few pulse
downbursts. Precipitable water values will also trend down, but
slow storm motions on saturated soils could result in an
isolated instance of flooding. However, the pulsey nature of
storms will likely limit their residence time. Fog may develop
again Friday night.

Ridging aloft builds further Saturday. The surface pattern
remains ill defined in the weak gradients, but weak surface high
could be implied. There will also be a weak backdoor boundary
which may attempt to approach between high pressure over New
England and a low off the coast. With all that said, the
forecast is not that much different than Friday without a
notable feature to focus storm development. Generally scattered
coverage is expected with an isolated flood threat remaining
possible for any slow moving storms over saturated grounds.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A typical summertime pattern will persist across the area through
the middle of next week, with seasonable heat and humidity, as well
as chances for thunderstorms each afternoon and evening.

On the synoptic scale, the pattern is expected to change very little
over the course of the long term period, with the stronger belt of
westerlies staying well to our north, and no strong frontal passages
to speak of. While there will be chances for showers and
thunderstorms each afternoon, the greatest coverage of storms will
likely occur on Monday as a shortwave disturbance aloft moves
through, providing a bit more large scale forcing for ascent. Ample
sunshine is expected through the morning hours each day. High
temperatures are expected to rise into the upper 80s to around 90
each day, with overnight low temperatures in the mid-upper 60s to
the west of the Blue Ridge, and then lower to middle 70s further
east.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Cloud decks remain patchy and variable, but guidance suggests
they fill in toward sunrise, with IFR conditions expected for
most areas (LIFR at CHO). While visibility may be reduced,
ceilings should prevail over fog this morning. These ceilings
will gradually lift through the morning and early afternoon.
Some scattered showers will also be possible but should not
carry additional impact. The longer residence time of the clouds
may hamper thunderstorm development today. Included a PROB30
group for DCA/IAD/MRB for the late afternoon, but it`s
definitely at the lower end of the probability spectrum. BWI/MTN
may just see some lingering showers. There is a greater chance
of storms at CHO, however. This threat rapidly diminishes during
the evening, with a pretty strong signal for fog the second half
of the night as skies start to clear. Some locally dense fog
can`t be ruled out.

Friday and Saturday will be similar that afternoon/evening
convection will be more scattered in nature and should be brief
in nature. Patchy fog, or possibly lower ceilings could develop
during the overnights/early mornings.

Prevailing VFR conditions are expected on both Sunday and Monday,
but showers and thunderstorms may lead to brief restrictions either
afternoon or evening. Winds will be light out of the south on
both Sunday and Monday.

&&

.MARINE...
Some brief marginal advisory level gusts occurred on the wider
waters earlier but appear to be diminishing. Otherwise, light
background winds are expected today through Saturday. Prevailing
direction will start southwesterly but become southeasterly over
the next few days. With the light flow, local variations will
occur. The main threat will come from gusty thunderstorms each
afternoon and evening, but overall that threat should be more
scattered in nature compared to Tuesday and Wednesday.

Sub-SCA conditions are expected over the waters on both Sunday and
Monday, with light southerly winds both days. Thunderstorms may be
possible during the afternoon and evening hours, potentially leading
to the issuance of SMWs.

&&

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

&&

$$

SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...KJP
AVIATION...ADS/KJP
MARINE...ADS/KJP