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fxus61 kpbz 151425 
afdpbz

Area forecast discussion
National Weather Service Pittsburgh PA
925 am EST sun Dec 15 2019

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

&&

Near term /through tonight/...

Morning update: no major changes made for this forecast period.

Previous discussion: scattered snow showers should end as broad
upper troughing flattens and high pressure builds. Temperatures
should stay slightly below the climatological average under west-northwest flow.



&&

Short term /Monday through Tuesday night/...
an initial shortwave ahead of a central Continental U.S. Trough is progged to
approach and cross the region tonight and Monday. Snow is expected
initially, with critical thicknesses and model sounding indicating
the precip should mix with or change to a period of freezing rain
roughly along and south of I 70 by Monday morning in warm, moist
advection. Issued a Winter Weather Advisory in this location in
coordination with surrounding National Weather Service offices. Areas further north
should stay snow, before a mix/change to rain occurs. A brief period
of freezing rain is possible Monday morning, though sfc temperatures
should be rising by the time this change occurs, so did not include
any additional areas in the advisory at this time.

Garrett County should see more prolonged freezing rain through the
day Monday, with a later ending time to the advisory there. More snow
is also expected, with 2-4 inches across the higher terrain of
Garrett County. Elsewhere an inch or two is expected in the advisory
area, with an inch or less for areas further north.

The central Continental U.S. Trough is expected to track east Monday and Tuesday
as a sfc low moves across the Tennessee and Ohio Valley regions. Additional
shortwave support and moist advection should increase precip coverage
later in the day Monday and Monday night. Much of the area should see
rain through locations north of pit could also see a wintry mix as temps
aloft warm, but the sfc temps remain cold. Precip should become light
and change to mainly snow Tuesday in cold advection behind the
exiting sfc low.

&&

Long term /Wednesday through Saturday/...
snow shower chances continue Wednesday with cold northwest flow and a
crossing upper trough. Generally dry weather is then expected through
the Friday under a building ridge ahead of a wrn Continental U.S. Trough.
Slight chances for precip return Saturday as the trough approaches.

&&

Aviation /14z Sunday through Thursday/...
widespread MVFR conditions are expected through much of the day
with low level moisture under a temperature inversion. Broad upper
troughing should also support scattered snow showers tonight this
morning, with localized vsby restrictions.

A return to VFR is expected by late afternoon/early evening as high
pressure briefly builds in. Mixing and a sufficient temperature
gradient should maintain wind gusts through late this afternoon. IFR
in snow is expected again late tonight with approaching low
pressure. Some of the snow could mix with freezing rain for ports
south of pit.

Outlook...
restrictions are likely to continue Mon and Tue with crossing low
pressure.

&&

Pbz watches/warnings/advisories...
Maryland...Winter Weather Advisory from 9 PM this evening to 7 PM EST Monday
for mdz001.
Ohio...Winter Weather Advisory from 9 PM this evening to 10 am EST Monday
for ohz057>059-068-069.
PA...Winter Weather Advisory from 9 PM this evening to 10 am EST Monday
for paz031-075-076.
WV...Winter Weather Advisory from 9 PM this evening to 10 am EST Monday
for wvz003-004-012-021-509>514.

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