Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Pittsburgh PA
1223 am EST Sat Mar 7 2015
a couple of weak disturbances will cross the region this weekend.
A warming trend is expected next week.
Near term /through today/...
overnight period in good shape. No significant changes needed.
Shortwave trough will swing through the region this afternoon. An
area of scattered snow showers should develop along the wave
mainly over the northern half of the region. With warm air
advection today...low level thickness will rise allowing for the
chance that a mix of rain and snow will occur...particularly late
in the afternoon.
Temperatures will moderate today with warm air advection aloft and
southwesterly flow at the surface.
Short term /tonight through Monday/...
during the evening hours...shortwave will quickly exit to the east
taking the upper level moisture with it. With the loss of ice
crystals into the lower cloud layer and a high snow growth
zone...snow production should end.
A weak cold front will cross the area late tonight setting up a
push of colder air through Sunday.
Models are continuing to show a stratocu deck parking itself over
the region through the weekend and into Monday. Its not out of the
question that patchy freezing drizzle could develop late tonight and
Sunday morning...but this would be primarily over the ridges.
The combination of the clouds and cold air advection will keep
temperatures down a bit on Sunday.
High pressure will settle in on Monday and the stratocu deck will
begin to erode.
Long term /Monday night through Friday/...
the extended period looks to be relatively quiet as zonal flow
sets up across the forecast area and we see a gradual warming
trend in temperatures...extending slightly above normal by
Aviation /05z Saturday through Wednesday/...
VFR will prevail through the immediate Post dawn period...but a
shortwave in northwest flow aloft will cross the region today
accompanied by general MVFR ceilings...with a period of IFR at fkl
and duj...and some scattered snow showers.
Outlook.../Saturday night through Wednesday/...
restrictions are possible into Sunday...with general VFR returning
thereafter and persisting into the middle of next week.