Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 041518

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1018 AM EST Mon Dec 4 2023

A clipper system will cross the area Tuesday into Wednesday.
High pressure will build over the region Thursday through Friday
night. A strong frontal system will likely impact the region
late in the weekend.


A potent mid/upper-level shortwave will traverse the Mid-
Atlantic through this evening bringing widespread mid and high
cloud cover. The low levels are dry and winds are downsloping
out of the west, so precipitation looks unlikely except perhaps
for a spotty flurry or sprinkle over the Allegheny Front. High
temperatures will range from the 30s over the higher terrain to
the 50s east of I-81/south of US-50.

A few extra flurries or a snow shower or two can`t be ruled out
along and west of the Allegheny Front tonight, but south-of-west
flow and shortwave ridging should cut down on anything more than
that. Further east, clouds will clear. Temperatures will fall
into the mid 20s to mid 30s.


Second and stronger upper level disturbance will begin to dive
from the western Great Lks Tue afternoon and reinforce the
trough pattern across the East. Expect clouds to develop quickly
by midday Tue with isold-sct rain showers expected at low
elevations and snow showers across the higher terrain. Rain may
also mix or change to snow along the Pennsylvania border Tue
night. Snow showers will persist across the Appalachian region
through Wed before trough axis shifts east of the region Wed
night. A few inches of snow are likely across the Appalachian
region which may require Winter Weather Advisories. In addition,
brief rain or snow squalls are possible Wednesday everywhere.
Low-level thicknesses suggest p-type would be snow north of
I-66 and rain south of there. Blustery Wed night with wind
chills in the teens and twenties.


Chilly temperatures continue on Thursday in the wake of the
aforementioned clipper low. High temperatures in the 40s can be

High pressure will shift offshore on Friday into Saturday, meaning
that we will see temperatures moderate a good bit. Highs in the mid
to upper 50s are expected, with lows in the 30s.

Moving into Sunday, eyes turn towards a potent upper-level trough to
our west. There is a lot of uncertainty at this point as to exactly
what the main impacts from this system will be as it moves in our
direction, as well as exactly when impacts may arrive. But there is
the potential for a potent low pressure system and cold frontal
passage. It will all depend on the track, so will have to monitor
for a potential heavy rain and/or severe weather threat as we get
closer in time and have a bit more consistency.


VFR conditions are expected through Tuesday. Mid and high level
broken/overcast conditions are anticipated today with W/SW wind
gusts to 15 kts possible. VFR stratocu is most likely to prevail
through Wednesday night in W/NW flow as a clipper system moves
through. Drops in CIGs/VSBYs are likely especially west of US-15
Tuesday night into Wednesday morning as the clipper brings a
round of showers, most likely in the form of snow for KMRB (with
a mix possible elsewhere).

VFR conditions expected Thursday and Friday with winds out of the
SSW on both afternoons at around 8 to 12 knots.


An enhancement to northerly winds is expected tonight over the
main channel of the Chesapeake Bay as a disturbance pushes to
the east. A clipper system will swing through Tuesday into
Wednesday with 25-30 kt gusts likely in its wake out of the
W/NW. Winds begin to taper a bit Wednesday night, especially
over narrower waterways, but 20-25 kt gusts likely persist over
the wider waters until at least daybreak Thursday.

Winds taper off on Thursday and Friday, with mo marine hazards
expected at this time.


MARINE...Small Craft Advisory from midnight tonight to 7 AM EST Tuesday
     for ANZ531>534-537-539>541-543.



MARINE...LFR/DHOF/CJL is the U.S. government's official web portal to all federal, state and local government web resources and services.