Area Forecast Discussion
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FXUS61 KPBZ 050544

Area Forecast Discussion
National Weather Service Pittsburgh PA
1244 AM EST Mon Dec 5 2016

Some locations in the higher elevations are expected to receive
freezing rain tonight. An unsettled weather pattern will continue
through the week, with much colder air arriving by Friday.


Area of precipitation is rapidly shifting eastward, as the
negatively tilted trough shifts northeastward, taking much of the
lift with it. While we will see an end to measurable
precipitation within the next hour or two, some drizzle may be
possible as dry air moves in aloft. PoPs were adjusted based on
the latest observations and trends, but have not added widespread
drizzle at this time.

Over these next couple of hours however, southeasterly flow and
low level instability continue support for snow and sleet in our
northern zones and some freezing rain in the ridges. Think that
the window for rain will be rather short over the counties north
of I-80 so Ive upped the snow accumulation in those areas. A
slushy 1-2 inches is likely in the northernmost counties through
this morning. In the ridges, temperatures are gradually warming,
with eastern Tucker most likely seeing rain at this time, but
values remain just at freezing in Garrett. Thus, will keep the
advisory going as advertised.

Cold advection on the backside of this system, though brief, may
allow for some wet flakes to mix in toward morning over the ridges before
subsidence ends precipitation across the entire region. But models
disagree on the depth of saturation of the boundary layer. Have
kept the low chance pops through just after sunrise today.

Despite high pressure settling overhead, cloud cover should limit
temperatures to just below seasonal averages today.


Clouds will stream back in Monday night in advance of a low
pressure system that will move across the region. As precipitation
moves in Monday night and Tuesday morning, many places could have
a brief period of freezing rain before warm advection changes all
precipitation over to rain by Tuesday afternoon. Have continued
with categorical pops through this time period, with rain changing
over to snow as it wraps up late Tuesday night into Wednesday.
High temperatures in the low to mid 40s on Tuesday will likely be
the warmest readings of the 7 day forecast.


Yet another system moves through Thursday, with a cold front
bringing another chance for precip. Most of this precipitation
would likely fall as snow, and behind the front temperatures will
plunge into the teens by Thursday night. Cold advection should
then prompt snow showers to continue through Saturday morning.
Temperatures will struggle to recover, but another cold front will
approach from the west Sunday.


The bulk of the precipitation will be pulling out over the next
couple of hours as low pressure rapidly moves off.  Widespread IFR
or low MVFR ceilings will be left in its wake for the rest of
the night into mid-morning Monday, along with some patchy

Northwest flow behind the system will keep ceilings MVFR into
the afternoon, but improvement to VFR is expected by sunset as
high pressure crosses. While clouds may break for a period this
evening, high clouds will already be advancing northward ahead of
the next system by midnight.

Restrictions are likely Tuesday and Tuesday night as the next low
pressure system crosses.  A strong cold front will bring more
restrictions by Thursday.


MD...Winter Weather Advisory until 4 AM EST early this morning FOR
WV...Winter Weather Advisory until 4 AM EST early this morning FOR


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