Area Forecast Discussion
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FXUS61 KPBZ 250438 AAC
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
1238 AM EDT Thu Aug 25 2016

.SYNOPSIS...
A couple of crossing disturbances will return rain chances to the
Upper Ohio Valley Region this morning, and again late this afternoon
and evening.

&&

.NEAR TERM /THROUGH TONIGHT/...
Changes for the midnight update included an upward adjustment for
precip probability as well as timing adjustments in response to
convection moving out of Ohio under a shortwave in zonal flow
aloft. In short, numerous showers and storms can be expected
through the predawn hours with a taper-off thereafter as the
supporting disturbances progresses eastward.  Lows are expected
to be around 10 degrees above seasonal levels given increased
dewpoints and lack of radiation.

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 today/this evening. Likely
POPS 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.

&&

.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. Given the
strength of the upper ridge, southward frontal penetration is
questionable, but will generally persist with a dry forecast
through Saturday as per the latest deterministic trends as flow
becomes zonal. Warm weather will continue as zonal flow across the
northern ridge periphery shunts warm air across the region.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Flow is expected to back to a southwesterly direction as an upper
high enhances and shifts towards the Mid-Atlantic. As a result of
the strengthening ridge, anonymously high surface temperatures
and upper heights are predicted by ensemble models and have led
to higher confidence in raising forecast temps early in the
period. Overall, hot and humid conditions can be expected in the
beginning of the long term until the passage of a shortwave on
Monday provides some relief from the heat. POPs were maintained in
association of the aforementioned shortwave as per the latest
Superblend guidance.

&&

.AVIATION /06Z 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 /THURSDAY THROUGH MONDAY/...
Periodic restriction chances should persist through Friday with
the approach and passage of a cold front.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$



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