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Area forecast discussion 
National Weather Service Pittsburgh PA
331 am EDT Thu Aug 25 2016

Synopsis...
a couple of crossing disturbances have returned rain chances to
the upper Ohio Valley region for this morning, and again late
this afternoon and evening.

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Near term /through tonight/...
changes for the morning update featured further adjustments to precip
probability in response to weakening convection under a shortwave
in zonal flow aloft. In short, numerous showers and isolated storms
can be expected through the predawn hours with a taper-off thereafter
as the supporting disturbances progresses eastward.

The midday period is expected to be dry given shortwave ridging
between disturbances. Temperature was thus adjusted upward toward
higher guidance; however, the next in series of disturbances is
progged to trigger another round of convection focused on a weak
front moving off the Great Lakes late this afternoon/this
evening. Likely probability of precipitation were maintained for extreme northern zones.
Increased flow aloft may support some severe thunderstorms, but
this potential is expected to be tempered via very warm mid level
temperature.

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Short term /Friday through Sunday/...
precipitation chances are projected to wane on Friday as surface
high pressure builds in the wake of a weak front. Have persisted
with a dry forecast through Saturday as per the latest, and
consistent deterministic trends. Warm weather will continue as
zonal flow across the Northern Ridge periphery shunts warm air
across the region.



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Long term /Sunday night through Wednesday/...
little change in pattern is indicated through the first half of
next week with the southern U.S. Upper high maintaining grip, but
with tropical system encroachment toward the southeastern coast. Shortwaves
with the zonal flow over the immediate area would support periodic,
and diurnally-supported precip chances for the long term. Low-confidence
slight to chance pops were maintained for that eventuality as per
the latest superblend guidance. Warm temperature can be expected
given the lack of any significant airmass alteration.

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Aviation /07z Thursday through Monday/...
showers and a few thunderstorms will encroach from the west
during the early portions of the forecast. Expect coverage and
intensity to continue to decrease overnight, so have only included
restrictions in a tempo group. Shortwave that has sparked the activity
will clear the area quickly this morning. Expect a quick return to
VFR conditions after sunrise.

Outlook /Friday through Monday/...
periodic restriction chances should persist through Friday with
the approach and passage of a cold front.

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Pbz watches/warnings/advisories...
Maryland...none.
Ohio...none.
PA...none.
WV...none.

&&

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