495
FXUS61 KLWX 180700
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
200 AM EST Tue Nov 18 2025

.SYNOPSIS...
A wave of low pressure approaching from the Ohio River Valley will
track along a stalled front over or just south of the Mid-Atlantic
through Wednesday. The front will likely remain stalled just to the
south through Thursday. Another area of low pressure may take a
similar path Friday into Saturday. High pressure will likely
return Sunday into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Early morning analysis shows clear skies and cold temperatures
as high pressure briefly ridges overhead. Upstream, low pressure
was taking shape over the Missouri River Valley. This low will
track across the mid Mississippi River Valley today, then up the
Ohio River Valley tonight.

A warm front developing ahead of the approaching wave of low
pressure will lift into the Mid-Atlantic this evening, likely
stalling across southern Virginia as high pressure holds firm to
the north. This sets up a warm advection/overrunning pattern. A
coupled upper jet, a stout mid-level shortwave, and low-level
WAA will work in tandem to produce a swath of precipitation
across the area. Precipitation likely stays west of I-81 through
midday before quickly expanding eastward this afternoon into
this evening. Precipitation will then exit late tonight.

Rain will be the dominant precipitation type for most of the
area, though a few wet snowflakes/sleet pellets are possible at
onset over portions of the Allegheny and Potomac Highlands, as
well as the Catoctin Mountains. Given the setup of high pressure
to the north and low pressure passing to the south, lingering
low-level cold air could prove hard to scour out in the typical
cold spots of eastern Garrett/extreme western Allegany Counties
in Maryland and perhaps into western Mineral County in West
Virginia. Some high resolution guidance depicts spotty light
freezing rain at times this afternoon and evening for these
areas. Have maintained a Special Weather Statement for this
localized/low-end potential, but have pushed the timing a bit
later and focused it slightly more to the typical "cold pocket".
Due to the localized and marginal nature of the threat, a
Winter Weather Advisory is not anticipated, but not totally out
of the question. Regardless, a few slick spots could develop
during the evening commute in the vicinity of western Maryland.

All in all, this will be a beneficial rain for the region given
ongoing drought conditions. Widespread rainfall amounts of a
quarter to half an inch are expected, focused mainly between
US-50/I-66 and I-70. Slightly lower amounts are possible near
the I-64 corridor which may be displaced slightly south of the
best forcing. Meanwhile, amounts could approach an inch for the
higher ridges of the Alleghenies. Although locally higher totals
embedded within the broader frontogenetic band are possible
across the northern third of the CWA, the progressive nature of
the wave, PWs less than 1 inch, minimal MUCAPE, and a lack of a
persistent easterly component to the low-level flow should put
a relatively low ceiling on high-end potential rainfall amounts.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Low pressure will depart into the Atlantic on Wednesday as high
pressure remains to the north and a front remains stalled to the
south (likely over the Carolinas). This sets up a wedge of high
pressure down the east side of the Appalachians Wednesday into
Thursday resulting in abundant cloud cover and muted diurnal
temperature spread (i.e. less difference between daytime highs
and overnight lows). Drizzle or light rain is possible at times
given light onshore flow, but appreciable rain seems unlikely
due to generally weak forcing for ascent and pockets of dry air
aloft. By late Thursday night, deeper moisture and forcing with
the next wave of low pressure begin to approach resulting in
increasing rain chances through daybreak Friday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
A split flow regime will persist to end the week. The northern
branch of the jet is much more amplified which will offer a great
influence to the local weather pattern. In particular, the primary
upper trough of interest is forecast to track from Manitoba toward
southern Quebec/northern New England on Friday through Saturday.
At the same time, what remains of a southern stream shortwave
ejects out of the Four Corners region toward the middle of the
country by late in the work week. These pair of systems
eventually reach the eastern U.S. on Saturday before the mean
upper trough moves offshore late in the weekend. In the wake,
ensembles are in half decent agreement of the flow aloft turning
more west-northwesterly by Sunday before heights briefly build
into early next week.

Friday appears to be the warmest day of the forecast period with a
frontal boundary near or just north of the area and southerly flow
ensuing. This warm up will not be dry, as rain showers are expected
with the front nearby. There is continued uncertainty with regards
to Saturday mainly due to where the fronts will be positioned.
If faster, Saturday may trend drier. Temperatures are also
sensitive to how much cloud cover is present. Regardless, it does
not appear to be a complete washout Saturday, but trends should
be monitored.

To begin the next workweek, high pressure looks to build in with
dry and more seasonable conditions expected.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Clouds will quickly increase and lower from west to east through
the day, accompanied by increasing rain potential. The typically
more pessimistic guidance may be a bit too quick in bringing
lower ceilings in this afternoon, but the overall pattern of
high pressure to the north and low pressure to the south with
overrunning aloft suggests that IFR ceilings will eventually
develop. MVFR likely encroaches on KMRB around 21Z-22Z, then
spreads into the metro TAF sites between 00Z-03Z this evening.
IFR may quickly follow across the north for KMRB and KMTN, but
could be delayed until late overnight for KBWI/KDCA/KIAD. Given
the track of low pressure and the low-level wind pattern, the
onset of lower ceilings could be delayed well into the night at
KCHO, but they may drop very quickly if/when they do develop.
Winds will be light through the TAF period, generally SE to SW.

Conditions may attempt to gradually improve on Wednesday, though
lower ceilings probably persist through Thursday given high
pressure wedging down the east side of the Appalachians. Winds
turn N/NE during this time with periods of drizzle possible.

Continued periods of restrictions are expected Friday with rain
showers around. Winds become southwest through the day, with
afternoon gusts of 15 to 20 kts expected. Thereafter, a pair of
frontal systems track through the first half of Saturday which
may afford additional restrictions. Saturday`s wind fields will
largely be out of the north.

&&

.MARINE...
A period of steady rain is expected from late this afternoon
through the predawn hours Wednesday. Light winds will shift
around to the southeast and south through this evening, then
switch back to the north and northeast tonight through Thursday
as a wave of low pressure passes by to the south. A period of
SCA conditions is possible in northerly flow Wednesday afternoon
as the low pulls away.

Small Craft Advisories may be needed Friday evening as winds
increase ahead of a pair of cold fronts. A breezy northerly wind
on Saturday offers a better chance for advisory-caliber winds.

&&

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

&&

$$

SYNOPSIS...DHOF
NEAR TERM...DHOF
SHORT TERM...DHOF
LONG TERM...CPB
AVIATION...DHOF/CPB
MARINE...DHOF/CPB