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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 302000
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
300 PM EST Mon Nov 30 2020

.SYNOPSIS...

Strong low pressure will move off to the northeast this
evening. High pressure will gradually build over the area by
Thursday morning. Another storm system may impact the area at
the end of the week or early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Severe wx threat is winding down and should be entirely over by
22Z/5PM EST. Low pressure is moving off to the northeast with
cold front clearing the entire the area by 00Z tonight if not
sooner. Conditions will improve east of the mountains, but over
the mtns, sharply falling heights will result in crashing snow
levels with any rain showers transitioning rapidly to snow
showers early this evening. Winter Storm Warning remains in
effect for Garrett County and Advisories for western Grant and
western Pendleton Counties where significant snow accumulations
are expected. Please refer to WSW for more details.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

Cutoff upper low will cross the area tomorrow with strong
DPVA over the area. This will result in mostly cloudy/cloudy
skies and nearly steady temperatures in the mid 40s. Winds will
remain brisk out of the WNW and gust to nearly 30 mph creating
wind chills in the mid to upper 30s and much colder over the
mountains. Snow showers will continue over the mountains through
Tue night.

Fair weather expected on Wed, but on the brisk side as upper low
moves east and subsidence inversion strengthens. Winds could
gust up to 30 mph with wind chills remaining in the 30s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...

Quite the interesting and active pattern continues for the latter
portion of this week into the weekend. Overall, guidance is in
fairly good agreement in regards to the long term forecast. A
retrograding low over northern Quebec persists while a double barrel
upper level low induces a quasi-Fujiwhara effect over the Southern
Plains. Slight ridging over the southeastern CONUS will keep surface
high pressure just offshore Thursday; keeping the region dry.
However, the upper level trough over Quebec will dive southward over
the Ohio Valley just enough where it will pick up one of the upper
level lows over the Southern Plains. As a result, a surface cold
front will push through the region Friday into Saturday; reviving
the risk for showers.

A Rex Block will then develop over the western CONUS, which will
amplify the upper level trough over the Eastern US. While the
placement of the trough will keep our region dry under a strong NW
flow, brisk conditions will likely return to the area for the
weekend before another storm system possibly approaches early next
week.

&&

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

Showers ending by 21Z or 22Z with cigs gradually improving to
VFR by 00Z tonight, but BKN cigs 035-045 will persist overnight
and part of Tue. Gusty W winds develop Tue with gusts to 25 kt.
Fair weather Wed.

VFR conditions are likely Thursday with high pressure offshore
inducing a southerly flow. Sub-VFR possible by late Fri PM due to
increasing chance for showers as the wind turns SE.

&&

.MARINE...

Gradient winds are diminishing, but showers and isolated
t-storms may still pose a risk of 34kt or greater winds and
isolated waterspouts. Winds dimnish overnight, but solid SCA
conditions are expected on Tue.

A light southwesterly wind is forecast Thursday as high pressure
passes to the south, becoming southerly Thursday night into Friday
as the high moves offshore. The wind may begin to increase as it
turns southeasterly ahead of a low pressure system approaching from
the Tennessee River Valley by late Friday.

&&

.TIDES/COASTAL FLOODING...

Moderate coastal flooding can`t be ruled out at Annapolis early
this evening. Otherwise, high end minor flooding is expected.
Raised CF.Y for Havre de Grace where observational trends
suggest minor coastal flooding is likely. Could get close to
minor at Straits Point in the next hour or two. Water level
should begin to drop more rapidly late this evening and
overnight as westerly flow develops.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Coastal Flood Advisory until 11 PM EST this evening for DCZ001.
MD...Coastal Flood Advisory from 8 PM this evening to midnight EST
     tonight for MDZ508.
     Coastal Flood Advisory until 11 PM EST this evening for MDZ014.
     Winter Storm Warning from 1 AM Tuesday to 7 AM EST Wednesday
     for MDZ001.
     Coastal Flood Advisory until 10 PM EST this evening for MDZ011.
VA...None.
WV...Winter Weather Advisory from 4 AM to 7 PM EST Tuesday for
     WVZ501-505.
MARINE...Small Craft Advisory from 6 PM to 10 PM EST this evening for
     ANZ530>532-535-536-538>542.
     Gale Warning until 6 PM EST this evening for ANZ530>543.
     Small Craft Advisory from 6 PM this evening to 6 AM EST
     Tuesday for ANZ533-534-537-543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...MSS
AVIATION...MSS/LFR
MARINE...MSS/LFR
TIDES/COASTAL FLOODING...LFR