Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 210056
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
856 PM EDT Mon Mar 20 2017

.SYNOPSIS...
A weak cold front will cross the region tonight. A stronger cold
front will cross the area Tuesday night. High pressure will
return Wednesday through Thursday night. A warm front will cross
the region Friday. Low pressure may affect the area Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 8pm, a broad upper trough is north of the Great Lakes
with low pressure over the Texas panhandle and an associated
warm front extending east to Kentucky. A weakening MCS is moving
southeast from Ohio to eastern Kentucky. This precipitation
looks to graze the far SWrn zones (Highland to Nelson Counties)
with isolated thunder until midnight.

A vort lobe associated with the MCS will shift across the area
after midnight which may should allow some showers to develop
across middle and lower sections of the CWA including southern
Washington DC suburbs. Min temps generally around 40F with low
40s near the Bay (water temps are low 40s).

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Area will be in northwest flow on Tuesday. The downsloping will
keep it dry, although its looking quite cloudy (we will be in
the baroclinic zone). A stronger cold front will cross late
Tuesday night. The thermal packing will be aloft (clearly
evident at 850 mb), so anticipate the front will be marked more
by a surge of wind. Precipitation continues to be pressed south;
have trimmed PoPs once again. There still will be a chase
between exiting moisture and approaching cold air, but with PoPs
very low, this should be a non-factor.

Wednesday and Wednesday night will largely be marked by cold
advection. This will be the coldest part of the upcoming week.
Entire area easily will be in the 20s by late Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
An area of high pressure will be overhead Thursday and Thursday
night. Dry air and chilly temperatures are expected across the
region.

This high pressure will move to the coast Friday and Friday night to
allow for a return flow and milder air to develop for the mid-
Atlantic.

A cold front will sag across the Eastern Great Lakes Saturday before
stalling across our region Saturday night. A chance for rain showers
will develop during this period.

A storm system will develop along the west end of this stalled front
on Sunday, keeping the chance for rain showers in the region. The
storm system will move east along the front toward the East Coast.
The chance for rain showers linger throughout Sunday night.

More rain showers could develop along an associated cold front that
should also stall across our region on Monday. Temperatures will be
more seasonable.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
VFR generally prevails through the rest of the week. A weak low
will move east across the area overnight with brief MVFR
cigs/vsbys possible.

Low clouds will be persistent Tuesday. Believe ceilings will be
low-end VFR. Higher based MVFR within reason. A secondary cold
front will be crossing Tuesday night, before the Wednesday
morning push. Gusts to 25 kt will mark the frontal passage.

VFR/northwest flow gusting up to 30 knots on Wednesday, with
decreasing winds through the end of the week.

&&

.MARINE...
Light winds through midday Tuesday. The direction will be
variable through Tuesday morning, with northwest flow then
prevailing. A NWly surge will cross the Bay Region with a
subarctic cold front late Tuesday night through Wednesday night.
Gales possible around sunrise Wednesday. SCA in effect midnight
Tuesday night through Wednesday and expected to continue through
Wednesday night.

High pressure moves overhead Thursday with southerly flow Friday
and Saturday ahead of the next cold front Sunday night.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from midnight Tuesday night to 6 PM EDT
     Wednesday for ANZ530>543.

&&

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



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