Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 161949
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
249 PM EST Mon Jan 16 2017

.SYNOPSIS...
High pressure will build over the area through tonight. A stationary
front over the southern mid-Atlantic states will move north as a
warm front Tuesday. A weak cold front will push through the area
early Wednesday. High pressure briefly returns Thursday followed
by another system Friday.

&&

.NEAR TERM /THROUGH TUESDAY/...
Extensive cloud cover remains through today...as low-level
moisture is trapped along and east of the Blue Ridge due to our
region remaining sandwiched between high pressure centered off
the northeast coast and a warm front over the far western
Carolinas. Most areas remain dry through the evening...with just
some spotty showers across central VA, the Mason Dixon line, and
the Highlands.

Warm front and shortwave energy will lift northward toward the
area tonight and into Tuesday...with overrunning precipitation
overspreading the western zones early Tuesday. Rain chances
increase across metro DC/Balt by daybreak...and peak near midday.
Upper-level energy weakens as it approaches the area and it also
skirts by to our north...so expect greater precipitation totals
across NY and PA. Around here...generally less than a quarter of
an inch...except in upslope areas across the Allegheny Front where
a half inch (to locally three quarters of an inch) is possible.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
While steadier rain ends by early evening Tuesday...scattered
showers remain possible until weak cold front pushes through the
area early Wednesday. Further...intense upper-level energy moves
over the region Wednesday...which could lead to at least some
isolated showers. Best chances for these would be across upslope
areas and near the Mason Dixon line. Otherwise...expect warm
weather with highs in the 50s to low 60s Wednesday.

Drying out everywhere late Wednesday as high pressure builds into
the area.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
High pressure over the region Thursday will slide to the East
Coast Thursday night. Dry conditions are expected with mild
temperatures.

A low pressure system over the western Ohio Valley will pivot
northeastward into the Lower Great Lakes region Friday into Friday
night. Some energy associated with this main low will push across
our region during the same time. Light to moderate rain will
gradually spread northeastward across the Shenandoah Valley early
Friday. Rain should reach the District of Columbia and surrounding
areas by Friday afternoon. Temperatures will remain mild with high
temperatures about 10 degrees above normal. Drier air will work its
way into our region from the west behind this wave low pressure
energy and escorted by high pressure building in from the Ohio
Valley.

Even though high pressure will be overhead Saturday into
Saturday night, a weak piece of energy could linger nearby
keeping clouds and perhaps a slight chance for rain showers in
the forecast later Saturday into Saturday night. Temperatures will
stay mild throughout the period. A separate area of high pressure
over New England could aid in the cloud cover as we look at an
onshore flow in the east and an upslope flow along the Blue Ridge
and in the Potomac Highlands.

High pressure will hang on Sunday and Sunday night as a low
pressure system develops and deepens over the Mississippi Valley.
This low could send additional energy into our region Sunday night,
bringing the chance of rain showers once again.

On Monday, the main low will try to pivot northeast, bringing a cold
front across the region. The threat for more rain showers exist
Monday with a continuation of mild temperatures.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...

MVFR...to locally IFR (especially KCHO)...conditions will
continue through the TAF period. Restrictions are a result of low
ceilings through tonight and then for both decreased
ceilings/visibilities beginning tomorrow morning through the
afternoon with rain showers. Improving conditions late Tuesday
into Wednesday as high pressure builds toward the area.

VFR conditions Thursday and Thursday night. Winds northwest
becoming south 5 knots Thursday. Winds south becoming southeast
less than 5 knots.

&&

.MARINE...

Light winds expected through Tuesday. Wind gusts could approach
marginal small craft criteria Wednesday afternoon behind the cold
frontal passage. Winds subside late Wednesday as high pressure
builds into the area.

No marine hazards Thursday and Thursday night.
&&

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

&&

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



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