Area Forecast Discussion
Issued by NWS Sterling, VA

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481
FXUS61 KLWX 070845
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
345 AM EST Wed Dec 7 2016

.SYNOPSIS...
High pressure builds into the area today. A reinforcing cold front
will pass through Thursday. Arctic high pressure returns to the
area Friday into the weekend. Another cold front crosses the area
early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Coastal low pressure continues to move out to sea early this
morning and high pressure will approach from the Ohio Valley later
today. A northwest flow between these systems will allow for drier
conditions along with increasing sunshine. Max temps will range
from the upper 30s to lower 40s in the mountains to the middle 50s
near Washington and Baltimore into central Virginia and southern
Maryland.

Surface high pressure will build overhead tonight...bringing dry
and seasonable conditions. A reinforcing cold front will pass
through the Ohio Valley late tonight while a potent jetmax in the
upper-level flow builds in from the southwest. This will bring
some clouds overnight...but little moisture will be in place so
the latest forecast remains dry.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The jetmax will pass through the area Thursday and the reinforcing
cold front will also pass through the area during this time.
Again...moisture remains limited so most areas may end up dry.
However...a couple showers cannot be ruled out ahead of the
boundary. Will continue with slight pops across southern Maryland
where the forcing and moisture have the best chance to line up.
Even across these areas...any precipitation should be light and
much of the day will turn out dry.

Canadian high pressure will build toward the area Thursday night
through Friday night and a blustery northwest flow will allow for
much colder conditions. Upslope snow showers are likely for
locations along and west of the Allegheny Front. Accumulations are
also likely during this time. Elsewhere...dry conditions should
persist.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Artic high pressure shifts overhead during the day Saturday. Highs
across much of the area remaining AOB 40F (i.e., around 10F
below normal). With high pressure overhead...expect lows early
Sunday morning in the 20s everywhere.

High pressure shifts offshore Sunday. With a southerly wind
component developing...highs reach back into the L/M40s across
much of the area. Cold front approaches the area early next
week...with most guidance bringing precipitation in late Sunday
into Monday. Winter p-type issues of all varieties could arise
with this system...though it is too early to determine areal
extent of any threat. Additionally, large QPF spread exists among
long range ensemble guidance.

High pressure returns to the area in the wake of frontal passage
late Monday into Tuesday...with dry weather returning...albeit
briefly.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Areas of low clouds and fog should gradually dissipate early this
morning as a northwest flow begins to usher in drier air. VFR
conditions will prevail today through this evening. An upper-level
disturbance may bring a period of MVFR cigs late tonight into
Thursday across the eastern terminals...but confidence is low at
this time. Otherwise...more VFR conditions are expected through
Friday night.

Northwest winds will gust around 15 to 20 knots today before
diminishing late this afternoon. Gusty northwest winds are
expected behind a cold front for Friday.

VFR conditions prevail Saturday through much of Sunday as high
pressure remains over the area. Some flight restrictions could
develop by early Sunday evening as precipitation begins to move
back into the area.

&&

.MARINE...
Coastal low will continue to move off to the east today while high
pressure approaches from the west. A northwest flow is expected
today and a Small Craft Advisory is in effect for the waters.

High pressure will build overhead tonight and light winds are
expected. A reinforcing cold front will pass through late Thursday
into Thursday night. Gusty northwest winds are expected behind the
boundary. A Small Craft Advisory may be needed Thursday
afternoon...but confidence is low due to timing uncertainties. A
Small Craft Advisory will be needed Thursday night through Friday
night...and a Gale Warning may be needed for portions of the
waters Friday. However...latest information suggest that SCA
conditions are more likely than Gale Conditions.

Winds drop back below SCA Saturday morning as large area of high
pressure builds overhead. Low-end SCA wind gusts could redevelop
Sunday afternoon in southerly flow ahead of cold front.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 8 AM this morning to 3 PM EST this
     afternoon for ANZ530-531-535-536-538-539.
     Small Craft Advisory until 3 PM EST this afternoon for
     ANZ532>534-537-540>543.

&&

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



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