Area Forecast Discussion
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FXUS61 KPBZ 251839
Area Forecast Discussion
National Weather Service Pittsburgh PA
239 PM EDT Tue Apr 25 2017
Building high pressure will return dry, and very warm weather to
the Upper Ohio Region for Wednesday.
.NEAR TERM /THROUGH WEDNESDAY/...
Upper level low pressure will continue to slowly trundle up the
East Coast tonight with increasing subsidence on the western
flank suppressing residual rainfall. Boundary layer moisture and
a generally warm column should hold morning lows about 7
degrees above the seasonal averages.
Insolation with rising heights/warm advection in response to a
deepening plains trough will maintain dry weather for Wednesday,
and drive temperature well above the averages. Expect readings
either side of the 80 F mark areawide.
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
-- Changed Discussion --Continued warm advection and mixing will support temperatures
well into the 80s on Thursday, but the aforementioned plains
trough is also progged to dig eastward and increase rain chances
as the day progresses.
While the low center is forecast to develop toward the James
Bay, models have been consistent in extending a negatively
tilted axis across the Upper Ohio region in the afternoon or
early eve. Should low/mid 80s temperature occur as projected
with a near 60 dewpoint, surface based instability would be
plenty sufficient to support a severe threat in the progged deep
layer shear field.
Mid level temperature in association with the fading ridge may
provide explosive-inhibition, but current thoughts are the
thermal trough may deepen the mid level lapse rates enough to be
problematic, especially in light of the developing wind
field/high shear environment. An additional point of interest:
NAM/GFS indicated mid level veer in association with a negative
tilt may support some splitting cells in addition to providing
an area of enhanced diffluence at peak heating. At any rate,
will begin a Hazardous Weather Outlook mention today with a
primary wind threat from short bowing segments supplemented with
a large hail threat.
Passage of this systems cold/occluding front will end precip
during the evening with Friday expected to remain mostly dry and
continued warm under a shortwave ridge.
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.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Shortwaves ejecting from a Rockies-to-Plains trough will support
periodic rainfall chance for the weekend, timing and placement
of which remains questionable given expectations of amplified
flow/warm sectorization of the Upper Ohio Region as the Western
States system deepens and digs eastward. Very warm temperature
will continue until that system shunts a front across the region
early next week.
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Ceilings will continue to bounce around this evening, with
localized MVFR conditions possible from HLG and east. Tonight,
remaining cloud cover will lower, but may begin to scatter out
as high pressure begins to build from the west. As skies begin
to clear west to east tonight, some terminals could see fog
development, especially towards daybreak.
Easterly winds at 10kts or less will gradually diminish
The next chance for general restrictions is expected with late
week low pressure.