Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 270130
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
830 PM EST Sat Nov 26 2016

.SYNOPSIS...
High pressure will move across the region through Sunday, then
move offshore on Monday, ushering in southerly winds and warmer
temperatures. A storm system will begin to approach the region on
Tuesday, but the associated cold front will not move through until
Wednesday or Wednesday night.

&&

.NEAR TERM /THROUGH SUNDAY/...
High pressure will continue to approach from the Midwest
overnight. A northwest flow will usher in dry and chilly
conditions with min temps ranging from the 20s in the mountains to
the lower and middle 30s near Washington and Baltimore.

For Sunday, high pressure and dry air will result in just a few
clouds and an increasingly less breezy day. Temperatures will be
fairly similar to today, but with less wind it will feel a little
less chilly.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
Sunday night will be the coldest of the upcoming stretch, with
high pressure allowing for fairly widespread decoupling of the
winds. Lows mainly in the 20s except in the usual warm spots (and
on ridgetops). Clouds increase Monday. There is a bit of model
disagreement on temperatures. The consensus shows southerly flow
by afternoon, but the GFS doesn`t have it at all, and therefore is
cooler. Will stick with the consensus for now.

The previous forecast seems to have a good handle on the precip
onset Monday night. Of note, it looks like a good chance
temperatures will warm at least for the second half of the night,
so no precip type issues like we sometimes have at onset.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A warm front will lift north across the region Tuesday morning,
followed by a cold front moving northwest to southeast Tuesday
evening. A persistent southerly flow will fuel rain showers
throughout the day Tuesday.

As the cold front slides across southern Maryland and east-
central Virginia Tuesday evening, there could be a brief break in
the rain shower activity into the overnight hours.

A second storm system is expected to develop along the tail-end
of the cold front over the interior Southeast U.S. Wednesday
morning. The storm should ride northeast along the front
Wednesday and Wednesday night, bringing more rain showers to
the region.

The storm system will continue to move northeastward toward
southern New England Thursday. High pressure will build in
behind the storm and its associated cold front Thursday and
Thursday night. Drier and colder air will filter into the
region.

An upper level trough of low pressure is expected to sag southward
into the region from the Eastern Great Lakes Thursday night and
Friday. There may not be a lot of moisture available to fuel any
showers with the trough. Plus, a downsloping flow over the
Appalachian Mountains could encourage a dry day Friday.

High pressure will build in behind the trough of low pressure
Friday night and Saturday. Dry and chilly conditions expected.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
Drier air on a northwest flow will allow for clouds to diminish
tonight. Northwest winds around 5 to 10 knots are expected
overnight...but there could few more gusts around 20 knots
Sunday. VFR conditions expected through Monday.

Outlook...
Conditions will quickly deteriorate to IFR or even LIFR as precip
onset occurs late Monday night or early Tuesday. Rain showers
expected through the day with gusty southerly winds. Low clouds
hang in for Tuesday night and a second round of showers Wednesday.
Could be yet a third round of showers and low ceilings either
Wednesday night or Thursday morning before drying and clearing
occur.

&&

.MARINE...
A Small Craft Advisory remains in effect for the Maryland
Chesapeake Bay and the lower Tidal Potomac River. However...it
will be marginal across the inlets as well as the Maryland
Chesapeake Bay north of Pooles Island. Winds may increase for a
period Sunday due to a deepening mixing layer. A Small Craft
Advisory is in effect for the waters. However...the wind field
will subside Sunday afternoon and the Small Craft Advisory may be
cancelled early. No marine concerns Sunday night through Monday
night.

Small craft advisories likely Tuesday with winds southerly 15 to
20 knots and higher gusts. Channeling may lead to gale force gusts
on Tuesday. Small craft advisory conditions are possible Tuesday
evening. Winds southerly 10 to 15 knots with higher gusts Tuesday
night. May be a second round of southerly channeling up the bay on
Wednesday.

&&

.TIDES/COASTAL FLOODING...
Water levels are dropping below normal. We could approach a foot
below normal tides before winds shift on Monday and the anomaly
starts to rebuild. The southerly channeling favors elevated water
levels, but our model output is not handling it very well this far
out. Bottom line is that minor coastal flooding is possible along
the bay Tuesday/Wednesday but uncertainty is high.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 6 PM EST Sunday for ANZ530>534-
     536>543.
     Small Craft Advisory from 6 AM to 6 PM EST Sunday for ANZ535.

&&

$$
SYNOPSIS...JCE
NEAR TERM...JCE/BJL
SHORT TERM...JCE
LONG TERM...KLW
AVIATION...JCE/BJL/KLW
MARINE...JCE/BJL/KLW
TIDES/COASTAL FLOODING...JCE



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