Area Forecast Discussion
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FXUS61 KPBZ 190541
Area Forecast Discussion
National Weather Service Pittsburgh PA
141 AM EDT Wed Apr 19 2017
A series of low pressure systems will keep periodic rain chances
in the forecast through late week.
.NEAR TERM /THROUGH TODAY/...
A shortwave and associated warm front should result in
increasing clouds and low showers chances through the day as
they approach and cross the region, though a lack of deep
moisture and ascent should be a limiting factor. Overnight lows
are expected to be 10-15 degrees above average, with daytime
highs 5-10 degrees above average.
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
A weak, de-amplifying wave will pass well to our north Wednesday
night, pulling a filling surface low with it. A weak boundary
will splay west to east across the area, stalling out due to the
broad ridge resident over the southeast CONUS. Rain showers are
probable along this boundary Wednesday night into Thursday, but
should remain largely disorganized.
Shortwave ridging will then occur briefly Thursday morning as
another system approaches from the west. The upper trough will
dig into the western Great Lakes Thursday afternoon as the
surface low moves through the southern Great Lakes. The
attendant cold front will generate showers and thunderstorms
Thursday evening/night fueled by marginal instability and
favorable uni-directional wind shear. Still some questions as
to how much instability can be generated ahead of the front, but
the current SPC marginal risk looks sufficient at this point.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Zonal flow behind the Thursday`s cold front will bring drier
weather in temporarily for Friday. The trend in operational
guidance is to push the weekend system a bit further south.
Still, looks like rain will be likely over the latter part of
the weekend as an upper-level trough deepens over the
Mississippi Valley. Temperatures initially knocked back by the
late week cold front will remain near seasonal average through
the weekend under general troughing.
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --VFR conditions will remain through early afternoon with a dry
column in place. Slow moisture advection will arrive as a weak
disturbance approaches by late afternoon into tonight. Expect
CIGs to lower to MVFR late afternoon, with some IFR in light
rain across northern ports expected late evening into the
overnight. Winds will generally be south 5-10 KTs.
Restrictions will be possible Thursday with low pressure and a
cold front. Widespread restrictions are possible Saturday and
Sunday with strong low pressure.
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