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FXUS61 KPBZ 300508

Area Forecast Discussion
National Weather Service Pittsburgh PA
108 AM EDT Thu Mar 30 2017

Wrapped-up low pressure will bring rain to the upper Ohio Valley late
Thursday through Friday.


Midnight update made to make only minor tweaks to the forecast
based on the latest observations and trends. Incoming thin
cirrus and strengthening warm advection may limit cooling 
overnight. Thus, low temperatures were bumped up slightly based
on the latest hi res guidance.

Occluded low will move slowly eastward today toward the upper Ohio
Valley. Much of the region should remain dry until late, however 
as we remain situated under an upper ridge. Only exception to 
this is north of I-80 where moisture spilling over the ridge and
isentropic ascent support some rain showers by this afternoon.
Opted to carry coverage wording for the precipitation expected
through this evening. Otherwise, daytime mixing should allow for
temperatures to warm to slightly above averages today despite
increasing cloud cover.


Showers will continue everywhere Friday morning, with the
chances for showers beginning to diminish Friday afternoon and
Friday night. Lingering low level moisture may keep widely 
scattered showers possible through the first part of Saturday 
before building subsidence brings an end to precipitation. Above
normal temperatures are forecast on Friday before dropping to at
or slightly below normal values for Saturday.


While the second half of the weekend will be dry, showers will
begin to threaten the area on Monday, with Monday night having
the greatest chance for showers. While showers could possibly
hold on into Tuesday, a bit of model uncertainty develops for
the timing of the next low pressure system to arrive. Some model
guidance shows rain moving in on Wednesday, with other guidance
delaying rain until Thursday. Temperatures will generally stay
close to or slightly above average for early April.


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.



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