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fxus61 kpbz 161059 
afdpbz

Area forecast discussion
National Weather Service Pittsburgh PA
559 am EST Mon Dec 16 2019

Synopsis...
a wintry mix of precipitation is expected through Tuesday with
crossing low pressure.

&&

Near term /through tonight/...
added a few more counties to the Winter Weather Advisory this
afternoon through Tuesday morning. Latest models have trended colder
aloft, with a band of heavier precip possible with enhanced lift
late this afternoon and evening. This precip should also result in
additional cooling aloft. Concern with the trend and timing of the
precip around the afternoon/evening commute, so issued a quick
expansion of the advisory for this potential.

Previous...an initial lead shortwave ahead of an approaching central
Continental U.S. Trough continue to support mainly light snow across the region
this morning. Areas generally S of I 70 could see a brief period of
light freezing rain before the precip ends this morning, so continued
the Winter Weather Advisory for that area.



Precip should diminish for most areas later this morning as the
shortwave support exits. Areas near Garrett County Maryland should still
see freezing rain through the day, where they are situated close to a
stationary sfc front. Southeast upslope flow should keep sfc temps there
below freezing.

Precipitation should increase again late this afternoon and tonight
as another shortwave approaches in SW flow aloft ahead of the main
trough. Warm advection should also result precip changing to mainly
rain tonight roughly S of a zzv-lbe line, with model soundings and
critical thicknesses indicating a wintry mix of snow, sleet and
freezing rain to the north of this line. Issued a Winter Weather
Advisory for this area beginning late in the afternoon. The Laurel
Highlands and Garrett County Maryland should continue to see freezing rain
as the east-southeast flow maintain sfc temps at or below freezing. Issued an
advisory for the Laurel Highlands through Tuesday morning, and
extended the Winter Storm Warning for Garrett County Maryland also.

Locally heavy rainfall is also possible tonight especially S of I 70
as a jet aloft enhances lift, and a sfc low tracks across WV.

&&

Short term /Tuesday through Wednesday night/...
the wintry mix should change to all snow in cold advection Tuesday
as the sfc low moves east/NE of the area, and the upper trough crosses,
though accumulation should be light. A reinforcing trough and sfc
cold front should result in scattered snow showers Wednesday they
track across the NE Continental U.S.. the snow showers should gradually diminish
Wednesday night as high pressure builds in. Temperatures should
average below seasonable levels.

&&

Long term /Thursday through Sunday/...
generally dry weather is expected Thursday and Friday as ridging sets
up across the region ahead of an approaching trough. The trough
should return slight/low chances for snow showers Saturday before
dry weather returns under high pressure Sunday.

&&

Aviation /12z Monday through Friday/...
restrictions expected through the taf period. Precipitation and IFR
restrictions will resume this evening as low pressure approaches the
region. A wintry mix is expected with the primary ribbon of freezing rain
and/or sleet running along a line roughly from zzv to duj. Farther
north of this line will likely see more snow...and south of the line
will lean more towards rain.



Outlook...
restrictions are likely through Tuesday with crossing low pressure.

&&

Pbz watches/warnings/advisories...
Maryland...Winter Storm Warning until 11 am EST Tuesday for mdz001.
Ohio...Winter Weather Advisory from 4 PM this afternoon to 11 am EST
Tuesday for ohz039>041-048>050-057-058.
Winter Weather Advisory until 10 am EST this morning for ohz057>059-
068-069.
PA...Winter Weather Advisory from 4 PM this afternoon to 11 am EST
Tuesday for paz007>009-013>016-020>023-029-073-074-076.
Winter Weather Advisory until 10 am EST this morning for paz031-075-
076.
WV...Winter Weather Advisory from 4 PM this afternoon to 11 am EST
Tuesday for wvz001-002.
Winter Weather Advisory until 10 am EST this morning for wvz003-004-
012-021-509>514.

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