Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 240217 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
917 PM EST Thu Nov 23 2017

.SYNOPSIS...
High pressure will build over the area through Friday. Another
cold front will approach overnight Friday into Saturday before
passing through Saturday night. High pressure returns for Sunday
and Monday before moving offshore Tuesday.

&&

.NEAR TERM /THROUGH FRIDAY/...

Clear and cold overnight under high pressure and light winds.
Low temps in the mid 20s except low 30s in southern MD and city
centers.

Friday will be a warmer day than today with some light return
flow developing as high pressure shifts south and east of the
area. Most areas will see highs between 50 and 55.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
A cold front will be approaching from the Ohio Valley by Friday
night, with a gradual increase in clouds after midnight from
west to east. At this point it appears all precipitation will
remain west of the Divide through daybreak Saturday, but the
southerly winds will allow us to remain above freezing all
night.

The cold front moves through the area on Saturday, but the
orientation of the system turns the winds from the west as it
passes through, causing rapid drying and downsloping. Thus the
best rain chances are in the Highlands and Shenandoah Valley,
though a slight chance of a brief light shower is in the
forecast further east. Probably not something that should change
your plans if you`re in the major population centers though.

The pressure gradient tightens behind the front on Saturday
night, which will increase winds to the 10-20 mph range. Not
exactly cold behind the front though (other than the way it
feels with the breeze), with lows still staying above freezing.
The persistent west winds will promote upslope snow west of the
Allegheny Front, with early indications of light accumulations
possible based on our probabilistic snow output.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
High pressure will dominate the region through Tuesday. Dry
conditions with plenty of sunshine and temperatures that will be
near or a few degrees below average are expected through the
period.

The high moves offshore Tuesday night to allow for a dry cold
front to slide across the region to the Tidewater of Virginia
Wednesday. Temperatures will be a couple of degrees milder.

A second area of high pressure will wedge itself southeastward
behind the cold front Wednesday night into Thursday. Temperatures
will be near average. We can`t rule out a couple of upslope rain
showers over the Appalachian Mountains or Blue Ridge Thursday with a
slight chance of rain showers across eastern Virginia and southern
Maryland as a possible weak low pressure system moves north along
the Carolina Coast.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Absolutely no flight restriction concerns for the terminals
through Friday night. Clouds increase Saturday morning with a
chance for a shower, mainly at MRB. Gusty winds 10-20 mph
Saturday night.

VFR conditions Sunday through Tuesday.

&&

.MARINE...
Light winds expected on the waters through Saturday. Behind a
cold front on Saturday night, winds will markedly increase and a
small craft advisory is almost certain for Saturday night into
Sunday.

No marine hazards Sunday night through Monday night. Could see
some gusts above small craft on the open Bay waters on Tuesday.

&&

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

&&

$$
SYNOPSIS...JE
NEAR TERM...LFR
SHORT TERM...JE
LONG TERM...KLW
AVIATION...JE/KLW
MARINE...JE/KLW



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