Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 280132
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
932 PM EDT Mon Jun 27 2016

.SYNOPSIS...
A surface trough will remain over the region through Tuesday,
shifting east as a cold front late Tuesday. High pressure will
build from the west through Wednesday, then Bermuda high pressure
will provide a south wind Thursday and Friday. The next cold
front crosses the area from the west Saturday, stalling over the
southern Mid-Atlantic Sunday.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 9pm, surface trough/cold front is stalling over central
VA and southern MD. It will remain roughly there until an upper
trough shifts across the area Tuesday. Scattered showers and
thunderstorms, which persist along this boundary, will continue to
shift northeast to southern MD through the rest of the evening
before diminishing after midnight. As noted previously, some
showers could linger through the night. Elsewhere, particularly in
clearer skies behind the cold front in NWrn zones, patchy fog
could develop. Lows upper 60s to low 70s with plenty of lingering
moisture.

Previous...
Surface trough will remain over eastern portions of the area
Tuesday morning, supporting at least isolated to scattered
showers. Meanwhile, cold front will approach from the west with
better mid-level height falls. Convection could activate along the
front during the afternoon as it cross the Blue Ridge and enters a
more moisture-rich environment. Deep layer shear is still
moderate, but a little stronger than today, so would think there
would be a better chance of isolated strong to severe storms. Weak
mid-level lapse rates will be a limiting factor. With stronger
flow, flooding should be less of a concern. Highs will reach the
mid to upper 80s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Cold front will push east Tuesday night, clearing any remaining
showers and storms. High pressure and drier air will build into
the area Wednesday and Wednesday night; however, upper level
troughing may result in some clouds. Temperatures and humidity
will be a little lower.

On Thursday, upper level troughing will persist, but low level
flow will become more southerly. This may support enough moisture
return to result in a few showers and storms, especially over the
higher terrain. Temperatures may bump up a couple degrees.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The Mid-Atlantic region will be under the influence of an upper
level trough late in the week. Southerly flow ahead of a cold front
will continue through Friday, however temperatures will be near
or below normal with max temps in the low to mid 80s. Showers and
thunderstorms will be possible both days. The front will slowly
move eastward Friday night into Saturday. An additional cold front
will approach Saturday afternoon. Showers and thunderstorms are
possible Saturday through Sunday. High pressure should build into
the region behind the second front Sunday night into Monday.
Showers may linger into Monday.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 01Z, a cold front is stalling over southern MD and central
VA. No more TSRA threats for the TAF sites this evening. Skies are
clearing behind the cold front with thick clouds along the frontal
zone. Fog is possible late tonight, most likely NW where clearing
will last longest. Maintained MVFR conds in 00Z TAFs except for
KCHO which is most climatologically prone for fog.

Scattered thunderstorms will develop along a cold front Tuesday
afternoon. DC/Baltimore the mostly likely affected area. There is
a better chance some of these storms could be strong. Generally
VFR with high pressure from late Tuesday night through Thursday
morning. Showers/storms may develop mainly SW of the metros
Thursday afternoon.

Sub-VFR conditions possible Thursday night-Saturday in SHRA/TSRA.

&&

.MARINE...
Southerly channeling on southern MD waters ahead of a stalled cold
front over northern section of the Bay and Tidal Potomac. Local
gusty showers possible rest of the evening. Behind the front
early Wednesday, westerly winds may also be close to SCA levels.
With high pressure to the north, sub- SCA conditions are expected
Wednesday night- Thursday night.

Sub-SCA southerly winds expected on the waters Friday-Saturday.

&&

.HYDROLOGY...
Heavy thunderstorms have tapered off/shifted southeast with the
cold front which is stalling over the central VA piedmont and
southern MD. locally heavy rain in showers/isolated thunderstorms
likely through the rest of the evening, but nothing that warrants
a flash flood watch.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ532-533-537-
     540-541.
     Small Craft Advisory until 6 AM EDT Tuesday for ANZ534-543.

&&

$$
SYNOPSIS...BAJ/ADS
NEAR TERM...BAJ/ADS
SHORT TERM...ADS
LONG TERM...HAS
AVIATION...BAJ/ADS/HAS
MARINE...BAJ/ADS/HAS
HYDROLOGY...lwx



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