Area Forecast Discussion
Issued by NWS
FXUS61 KPBZ 300811
Area Forecast Discussion
National Weather Service Pittsburgh PA
411 AM EDT Thu Mar 30 2017
Wrapped-up low pressure will bring rain showers to the upper Ohio
Valley late today through Friday.
.NEAR TERM /THROUGH TONIGHT/...
Occluded low will move slowly eastward toward the upper Ohio
Valley today. Much of the region should remain dry until late
with the exception of the counties north of I-80, where
moisture spilling over the ridge and isentropic ascent support
some rain showers by mid morning through the afternoon. Opted
to carry coverage wording for the precipitation expected through
this evening as outside of the aforementioned counties, it
appears precipitation will be isolated at best given what is
progged by most of the hi res model guidance and the indication
that we will be in a dry-slot. Otherwise, daytime mixing should
allow for temperatures to warm to slightly above averages today
despite increasing cloud cover.
Better support for rain is expected tonight as the filling low
pressure system takes on a slight negative tilt, supporting an
area of diffluence and upper level lift over the region in most
of the deterministic guidance. Limited instability, with a
strong capping inversion suggests leaving out the mention of
thunder at this time.
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Rain showers will continue early Friday as the upper low moves
overhead. It appears that a dry slow will bring to an end the
widespread precipitation by midday, but scattered showers and/or
drizzle will likely continue with low level moisture trapped
under building subsidence inversion through Fri night.
Surface ridge will start to build overhead on Saturday, but
northwest flow and cold advection will likely keep skies cloudy
for a good part of the day. High pressure will support dry
conditions on Sunday.
Temperatures will remain just slightly above averages on Friday
and return to seasonal values for the weekend.
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Active weather pattern continues starting with the approach of
the next low pressure system sometime Monday. With plenty of
uncertainty apparent in the new model runs, especially in
regard to low placement evolution, opted to use a model blend.
Temperatures will generally stay close to or slightly above
average for early April.
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
Though general VFR is expected for today, marred by possible
scattered showers this afternoon, a gradual deterioration can be
expected late as deep low pressure shunts moisture and develops
a tightening pressure gradient over area terminals.
Showers, general MVFR, and low level wind shear can all be
expected after dark tonight.
Outlook... Restrictions are likely through Saturday as broad
low pressure moves slowly across the region.