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-- Discussion containing changed information from previous version are highlighted. --
396
FXUS61 KLWX 131934
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
234 PM EST Fri Dec 13 2019

.SYNOPSIS...

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Low pressure will move north up the East Coast tonight and Saturday.
High pressure will return briefly on Sunday before another system
potentially affects the region Monday into Tuesday. Cold high
pressure will then follow for the middle of next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH SATURDAY/...

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Rain continues for most areas along and east of the Blue Ridge
Mountains. Temperatures have risen above freezing for most of our
region but near to below freezing temperatures continue for portions
of western Maryland, the eastern panhandle of West Virginia and
northern Virginia. These freezing temps continue to erode and we
expect most areas to be above freezing by 3pm with portions of
western Maryland remaining below freezing through 5 pm. Freezing
rain and drizzle will continue to be possible for parts of western
Maryland, Northern Virginia, and eastern West Virginia. The threat
for wintry precipitation has mostly diminished and remains focused
to this afternoon.  Temperatures should max out today in the upper
30s to low 40s. with overnight lows this evening in the 30s.


Rain is expected to continue through early Saturday afternoon as the
upper low  moves northward over our region. General trend has the
rain moving out of our region by Saturday evening sometime around
00Z. As the main upper low moves through our region this evening
into early tomorrow, rain may become moderate at times which could
lead to decreases in visibility especially over the higher
elevations. Temperatures on Saturday will be warmer then today in
the mid to upper 40s to low 50s. This indicates we are expecting
mainly a rain threat on Saturday.
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&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...

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Rain will start to diminish after 18Z and be fully out of our region
by 00Z Sunday other than some upslope induced rain and snow showers.
A westerly flow will form as the surface low pressure system lifts
to our northeast. The westerly flow will lead to upslope showers
over the western parts of the Allegheny Mountain range with some
these showers falling as snow. Currently we have potions of the
elevations receiving up to a few inches of snow. The upslope induced
showers should diminish by Sunday morning

High pressure will briefly build over our region late Saturday and
through Sunday. Should become mostly clear on Sunday with some mid
to high level clouds lingering along the Allegheny Mountain range.
Temperatures will be warmer in the 40s to low 50s during the day
with cooler temps in the 30s for Sunday night.


A warm front will lift through our region late Sunday into early
Monday. The shield of precipitation associated with this boundary
will start to affect our area late Sunday evening with outer
portions of the DC metro near Sunrise on Monday. Areas north and
west of the I-95 corridor may experience periods of wintry mix in
the form of rain and snow with best areas for snow being northern
Maryland, Norther Virginia and West Virginia. Any wintry mix will
depend on the temperatures Monday morning and the timing of the
precipitation.
-- End Changed Discussion --


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...

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Low pressure moving from the mid MS valley through the OH valley
Sunday into Monday will bring another threat of overrunning precip.
Some light mixed p-type is possible at onset, but with sfc and 850
mb low centers passing well northwest of the area, expect bulk of
the precip to fall as rain with only light wintry precip possible.
Cdfnt will cross the area Tue afternoon with rain/showers ending
with frontal passage. Winds begin to increase Mon night from the SSW
and then increase further on Tue from the NW as pres gradient
tightens between low pressure offshore and building high pressure
from the west. Think  gales are possible, but wind advisory
headlines appear unlikely at this time. Much quieter wx pattern sets
up for the rest of next week but with more seasonable cool
temperatures for mid to late Dec with highs in the 40s and lows in
the 20s.
-- End Changed Discussion --


&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...

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Rain continues for all terminals leading to mainly IFR conditions
with brief periods of LIFR restrictions. I believe all terminals will
potentially experience periods of LIFR conditions but I didn`t feel
confident on a specific time that LIFR conditions could occur. The
best chance for LIFR restrictions will be when the moderate rain
moves through our area overnight and I have tried to indicate that
in the TAF`s with ceilings hovering near LIFR thresholds. Visibility
will likely be restricted to IFR to MVFR during light to moderate
rain. I believe the two areas that I have the highest confidence for
LIFR conditions will be MRB and CHO terminals since both tend to
restrict much easier. IFR conditions will likely continue through
Saturday morning becoming more MVFR late Saturday morning and into
the afternoon periods as the rain starts to taper off. VFR
conditions are expected Saturday evening and through Sunday.

More rain is expected late Sunday into Tuesday with some very light
wintry precip possible at onset, but bulk of precip should be rain.
Gusty winds Mon night and then windy Tue with gusts to 35 kt
possible.
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&&

.MARINE...

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Small Craft Craft advisories arent expected through Saturday
morning. As the surface low pulls off to the north, winds will pick
up over the waters. Small Craft Advisories will likely be needed for
Saturday afternoon through Sunday afternoon.

Small Craft Advzy conditions likely Monday afternoon and night with
gales possible Tuesday. Continued SCA conditions likely through the
middle of next week.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None.
MD...Winter Weather Advisory until 3 PM EST this afternoon for
     MDZ003-004.
     Winter Weather Advisory until 6 PM EST this evening for MDZ501-
     502.
VA...Winter Weather Advisory until 3 PM EST this afternoon for
     VAZ026>031-040-501-505-507.
WV...Winter Weather Advisory until 3 PM EST this afternoon for
     WVZ050>053-055-501-502.
     Winter Weather Advisory until 6 PM EST this evening for WVZ503-
     504.
MARINE...None.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG
LONG TERM...LFR/JMG
AVIATION...LFR/JMG
MARINE...LFR/JMG