Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS61 KPBZ 101958

Area Forecast Discussion
National Weather Service Pittsburgh PA
258 PM EST Sun Dec 10 2017

Cold temperatures and periodic snow chances can be expected for
the coming week.


Light snow showers will be possible overnight as a shortwave
crosses the region. Accumulations will be minimal as latest
forecast soundings show moisture and temperature profiles not
favorable for snow growth. Overnight lows again will be slightly
below average.


After a dry and slightly warmer day, the longwave trough that
has persisted over the northeast will deepen as a strong jet
core enters the backside of the trough. Light snow will develop
Monday night as moisture and lift increases ahead of an
approaching shortwave. A couple inches looks likely across
northern zones closer to the surface low by daybreak...with
lesser amounts farther south. A second wave will quickly follow
on Tuesday...reinforcing the longwave trough and shifting the
trough axis east. This will set up strong cold air advection as
flow aloft turns to the northwest. Lapse rates and inversion
heights will quickly increase and allow for a long duration of
lake effect snow potential across the I-80 corridor beginning
Tuesday through Wednesday.

Overall, minimal change was made to the inherited forecast and
the potential for heavy snow across northern counties
remains, therefore, the winter storm watch remains in effect for
Monday night through Wednesday.


An upstream shortwave is projected to back flow to the west on
Wednesday night, thus ending lake enhanced snow, before the reinforcing
front spawns more snow showers on Thursday, and initiates more
cold for Friday. Thereafter, another upstream trough is projected
to flatten flow and moderate temperature briefly back toward
the averages before cold frontral passage drops them again for
the start of the new week.


MVFR cigs will continue to lift over the next couple of hours in
advance of the next fast moving shortwave, progged for tonight.
All terminals should still see a period of VFR, with
deterioration once again as the wave passes. Confidence in
visibility restrictions is relatively low given the lack of
moisture and lift, but brief MVFR and IFR restrictions are

Southwest wind will briefly veer westerly before shifting back
to the SW tomorrow in advance of a more potent system, progged
for Mon night.

The next chance for widespread restrictions will come with low
pressure progged for Monday night/Tuesday with restrictions
continuing through midweek.


PA...Winter Storm Watch from Monday evening through Wednesday
     afternoon for PAZ007>009-015-016.


$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.