Scientific Forecaster Discussion
fxus61 kpbz 141950
Area forecast discussion
National Weather Service Pittsburgh PA
250 PM EST Sat Dec 14 2019
snow will continue through tonight with the passage of a upper-level
trough. Dry conditions return late Sunday under building high
Near term /through tonight/...
A low pressure system will continue to track east this evening, with
backing wind and cold advection snow will prevail. With warm
surface temperatures accumulation will be light around the Pittsburgh
metro; higher terrain and areas north of I 80 may see an 1-3 inches.
Wind gusts will increase throughout the night, especially in the
ridges, due the pressure increase in the wake of the cold front.
Short term /Sunday through Monday night/...
Widespread snow should taper off during the early morning hours as
the main trough axis advances into New England. Lake and terrain
enhancement should maintain snow showers, though less than optimal
westerly wind direction and a lack of decent moisture in the
dendritic layer should limit amounts.
Isolated snow showers may return briefly tomorrow as low-level trough
advances across central Ohio. Dry weather should return by late
Sunday afternoon under building high pressure.
A developing sfc low in response to the approaching trough, should
track from Central Plains to the Ohio Valley region late Sunday night
and Monday, returning precip to the forecast. Model soundings and
critical thicknesses indicate snow is likely initially Sunday night
and Monday morning, with a transition to mainly rain from S-N.
There could be a brief wintry mix during the transition early Monday.
At this time, it appears an inch or two of snow will be possible for
some areas before the transition. Some locally heavy rainfall is
also possible due to the quasi-stationary boundary.
Long term /Tuesday through Friday/...
The central Continental U.S. Trough should maintain precipitation chances
through early Wednesday as it crosses. Dry weather is expected
near the end of the week under a building high pressure. Colder than
average temperatures should return to seasonable levels by Friday.
Aviation /19z Saturday through Thursday/...
widespread IFR/LIFR will continue through the afternoon as a mid-
level trough continues to cross the area. The changeover process from
rain to snow is already underway and will continue from west to east
this afternoon. Improvement to low-end MVFR is forecast for tonight
as the trough pulls east, although scattered snow showers will
continue with brief visibility restrictions possible. Snow showers
will become isolated by the end of the taf period, with continued
slow ceiling improvement to high MVFR.
Gusty west-northwest wind of 15 to 25 knots will continue into the evening
horus with a tight surface pressure gradient. The wind will start to
relax late tonight/Sunday morning as high pressure moves up the Ohio
restrictions are likely again on Monday and Tuesday with The Crossing
of another low pressure system.