Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 280137
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
837 PM EST Sun Nov 27 2016

.SYNOPSIS...
High pressure will crest overhead this afternoon and tonight, then
move offshore on Monday. Upper energy from a large low pressure
system over the upper midwest will move into the region Monday
night and Tuesday, followed by a deepening surface low that moves
across the area Wednesday night through Thursday.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
High pressure will remain over the region tonight. High clouds
will increase well ahead of a storm system over the central
CONUS...but current thinking is that the cloud deck should be thin
enough for radiational cooling. Therefore...bumped the temps down
a few degrees in rural areas and sheltered Valleys. Min temps will
range from the lower and middle 20s in the colder valleys and
rural areas to the upper 30s in downtown Washington and Baltimore.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Increasingly active weather then expected as the week progresses.
Strengthening low pressure center across the central US Monday
will eventually weaken, fill, and slowly move eastward into the
Great Lakes Tuesday and into Wednesday. This will slowly push a
frontal zone towards the region, with strong southerly flow out
ahead of it, bringing with it milder and wetter conditions.

Will see a continued increase and thickening of the cloud deck on
Monday. Light and variable winds in the morning will give way to a
developing southerly flow. Highs by the afternoon reach the 50s
area-wide.

A strong push of warm air advection and energy aloft will then
make the move towards the region Monday night and into Tuesday.
Winds at 850 mb increase markedly and by Tuesday morning reach 60
knots. While not expected to reach the surface at most locations,
gusts up to 50 mph are possible across the higher elevations of
the Allegheny and Blue Ridge Mountains, and a Wind Advisory may
be needed. Rain showers will overspread the region during the
overnight hours and into the day on Tuesday. Mixing may increase
a bit during the day on Tuesday as well, so breezy conditions
likely for most locations during the day. Lows Monday night in the
40s climb into the 60s on Tuesday.

There looks to be a lull in the action Tuesday night, with a lower
chance of rain showers. Should be a mild night with lows not
dropping out of the 50s in many locations. Will also likely be
areas of fog with lingering low level moisture and moist and mild
air aloft.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
A storm system is expected to develop along the tail-end of a cold
front over the interior Southeast U.S. Wednesday morning. The storm
should ride northeast along the front Wednesday and Wednesday night,
bringing more rain showers to the region. Temperatures will be on
the warm side of things with a gusty breeze.

The storm system will continue to move northeastward toward
southern New England Thursday. High pressure will build in
behind the storm and its associated cold front Thursday and
Thursday night. Drier and colder air will filter into the
region.

An upper level trough of low pressure is expected to sag southward
into the region from the Eastern Great Lakes Thursday night and
Friday. There may not be a lot of moisture available to fuel any
showers with the trough. Plus, a downsloping flow over the
Appalachian Mountains could encourage a dry day Friday. However,
higher elevations in the Appalachians could encounter a couple of
snow showers Friday into Friday night.

High pressure will build in behind the trough of low pressure
Saturday and Sunday. Dry and chilly conditions expected each day.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
VFR and tranquil flying conditions expected through Monday
increasing cirrus overnight and into Monday morning. Light and
variable winds tonight also give way to a developing southerly
flow on Monday. Conditions will deteriorate Monday night and into
Tuesday as rain overspreads the region bringing periods of MVFR
and IFR. With increasing low level wind field, low level wind
shear is also expected. Some brief improvement is likely Tuesday
afternoon along with breezy southerly flow, with additional low
ceilings/visibilities possible Tuesday night in fog/stratus.

IFR to LIFR conditions expected due to rain showers Wednesday and
Wednesday night. Winds southeast to south around 10 knots with
higher gusts Wednesday. Winds south becoming west around 10 knots
Wednesday night.

&&

.MARINE...
Winds will diminish tonight with high pressure building overhead.
A southerly flow will develop Monday as high pressure moves off to
our east. Winds may approach SCA criteria Monday afternoon,
increasing further Monday night. Therefore SCA is in effect for
all waters Monday evening and Monday night. The strongest period
of winds is expected Tuesday, when a Gale Warning may become
necessary. Winds will then decrease somewhat Tuesday night.

Small craft advisories likely Wednesday. Winds southerly 10 to
15 knots with gusts in excess of 20 knots Wednesday. Small craft
advisories possible Wednesday night as well with winds shifting
to the west and gusting to 20 knots Wednesday night.

&&

.TIDES/COASTAL FLOODING...
Monday through Wednesday will feature a strong southerly fetch up
the bay coupled with a new moon and deepening low pressure. Will
continue to monitor the potential for coastal flooding.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 6 PM Monday to 6 AM EST Tuesday for
     ANZ530>543.

&&

$$
SYNOPSIS...MM
NEAR TERM...BJL/MM
SHORT TERM...MM
LONG TERM...KLW
AVIATION...BJL/MM/KLW
MARINE...BJL/ADS/MM/KLW
TIDES/COASTAL FLOODING...MM



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