Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 181844
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
244 PM EDT Thu Aug 18 2016

.SYNOPSIS...
High pressure builds in through Saturday with a cold front
crossing the area Sunday. High pressure returns for the first
half of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest obs this afternoon indicating weak boundary to the south of
the CWA. Light northwest to west flow injecting in drier air, with
dew points in the 60s to low 70s. Meso models still suggesting a
stray shower or thunderstorm could pop up, mainly terrain driven,
through the late afternoon/early evening with just enough
instability still in place. Anything that does form will be brief
and sub- severe. Precipitation will taper off by the end of the
evening with loss of daytime heating. Dry weather through the
night, with patchy fog possible in the valleys.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
High pressure centered to the southwest will nudge into the region
on Friday. Initially dry conditions Friday morning. However, a
passing upper level disturbance by the afternoon combined with
marginal instability could provide enough forcing to trigger
afternoon showers and thunderstorms. Not anticipating anything in
the severe nature, but would be more scattered in nature compared
to this afternoon. Loss of the diurnal heating will suppress any
thunderstorms Fri night, but with the shortwave energy still in
the region, isolated showers are possible overnight. Another
shortwave on Saturday with a similar surface setup will provide
yet another day of scattered showers and thunderstorms, still
remaining sub-severe. Temps during this time period just slightly
above normal.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
A moderate cold front is expected to move slowly eastward across
the Great Lakes region Sunday. This front could spawn a few
thunderstorms, mainly in the afternoon and along and west of the
Blue Ridge Mountains.

Showers and thunderstorms could linger Sunday night and Monday as the
front moves toward the Chesapeake Bay and possible stalls just east
of the bay.

High pressure will build in behind the front Monday night and linger
through Wednesday. Drier air and slightly cooler temperatures are
expected. High pressure will weaken Wednesday night and Thursday
and move east. A return flow will enable temperatures and humidity
to increase slightly.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Generally VFR conditions for the TAF period. Isolated
showers/thunderstorms possible, mainly KCHO/KMRB/KIAD this
afternoon and then again Friday afternoon. Scattered showers and
thunderstorms possible all TAF sites Saturday. Winds through
Saturday generally less than 10 knots from the W-NW.

IFR conditions at MRB and CHO terminals Sunday morning; MVFR
conditions at other terminals. IFR conditions at all terminals
Sunday afternoon and night. Winds southeast Saturday night
becoming south Sunday then southwest Sunday night.

&&

.MARINE...
Sub-SCA conditions on all the waters through Saturday. An
isolated shower or thunderstorm is possible each afternoon which
could bring gustier winds.

No marine hazards expected Sunday through Sunday night. Winds
south becoming southwest around 10 knots.

&&

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

&&

$$
SYNOPSIS...Sears
NEAR TERM...Sears
SHORT TERM...Sears
LONG TERM...KLW
AVIATION...Sears/KLW
MARINE...Sears/KLW



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