Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 151402
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1002 AM EDT Sun Oct 15 2017

.SYNOPSIS...
High pressure over the area will weaken rapidly through
today. A cold front will push into the Mid Atlantic tonight
followed by a return to high pressure early in the week and hold
through the end of the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The day started with widespread low clouds, areas of drizzle,
and patchy fog. The 12z LWX RAOB depicts a 2000 ft thick
saturated layer trapped beneath a surface inversion. This is
thicker than forecast yesterday, so it will take longer than
previously advertised to erode. On the bright side, literally,
satellite pictures do indicate mostly clear skies west of the
Blue Ridge, aside from a patch of clouds acrpss the Potomac
Highlands. This is further along than this time yesterday, and
mixing should be better. Combining these two puzzle pieces
suggest clearing by/during early afternoon, which is what
short-ranged consensus forecasts predict. Have therefore gone
cloudier than going forecast.

Cloudier will mean cooler as well. High temperatures forecasts
in the Shenandoah Valley have been left close to unchanged.
However, backed DC/Baltimore metro forecasts down to mid-upper
70s...again, with support of short-term consensus guidance.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
Cdfnt will cross the area this evening with showers likely in
the west early and then spreading east overnight. Gusty NW
winds will also accompany the front. Showers will linger across
srn MD through late morning Mon. Then, clearing Mon afternoon
with breezy NW winds with gusts up to 25 mph. Much cooler Mon
and Mon night. Winds diminish Mon night under building high
pressure. Areas of frost will be possible Tue morning as
temperatures drop to the mid 30s under clear skies and light
winds.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
There`s little change in the 00Z guidance for the extended forecast
period, and thus still little in the way of weather impacts. While
its center will wobble some, high pressure will remain squarely over
the area through the end of the week. A weak/decaying cold front
will pass through New England late in the week, which will turn
winds to the north, but otherwise have little moisture or thermal
contrast. Aloft, the pattern will continue to amplify into a west
coast trough/east coast ridge by Friday and Saturday. Temperatures
will be 5-10 degrees above normal through the period.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
Low clouds and some fog affecting the terminals. Anticipate
gradual clearing through midday, with VFR CHO/MRB by noon, and
metro hubs during the early afternoon.

A cold front will cross the area this evening with a chance of
showers. Winds shift and become NW with gusts up to 25 kt Sun
night and Mon. Winds begin to diminish Tue.

No significant weather expected Wednesday and Thursday with high
pressure.

&&

.MARINE...
SCA conditions expected later today through midday Tue. Gusts up
to 30 knots expected over the lower Bay Mon.

Light winds are expected Wednesday and Thursday with high pressure
over the region.

&&


.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EDT Monday for ANZ530>534-
     537>543.
     Small Craft Advisory until 6 PM EDT Monday for ANZ535-536.

&&

$$
SYNOPSIS...LFR
NEAR TERM...HTS
SHORT TERM...LFR
LONG TERM...ADS
AVIATION...HTS/LFR/ADS
MARINE...LFR/ADS



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