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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 221127
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
727 AM EDT Thu Jun 22 2017

.SYNOPSIS...
Chances of showers and storms will continue into the weekend.
Cooler weather arrives next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Morning update made to make minor adjustments to temperature
and dewpoint this afternoon based on latest observations and
trends.

Previous...
Upper level heights will rise today, which will assist in
dragging the stalled boundary northward. This will in turn allow
the more humid air to overspread much of the region by late in
the day. As heights rise, another shortwave will ride over top
of the weak ridge and provide the risk for afternoon showers and
storms, mainly north of PIT. This wave will also flatten the
ridge by late in the day. With the increasing humidity, surface
temperatures will rise with warm advection and increasing mixing
heights.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
More substantial upper level energy will stream northward from
the lower Ohio Valley tonight. These waves will follow
the intensifying southwest flow aloft, as the remnants of TS
Cindy move over the Lower Mississippi Valley. Deep moisture,
tropical in nature, will also stream northward which will bring
widespread rain and storms to the area late tonight through
Friday night. Warm rain process will develop on Friday,
creating a scenario for very efficient rainfall. As the rain
overspreads the region, a surface cold front will move across
the Upper Midwest, reaching Western Ohio by late in the
afternoon. It is a good bet that rainfall will intensify late
tonight and then ahead of the boundary Friday afternoon, so the
eastward progression of the front will need to be monitored
closely in future model runs. In addition to closely watching
the progression of the front, where the remnants of TS Cindy go,
once it phases in with the upper level flow, will also be
critical.

It will take all of Friday night for the front to exit to the
east, meaning the risk for heavy rain will continue into early
Saturday.

Drier air sags through the area on Saturday behind the exiting
front. This will allow for the area to finally start to dry out
and cool down.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A stark shift in the upper level pattern looks to occur by early
next week. Model and ensemble projections all favor deep
troughing settling over the region by that juncture. With this,
much colder air aloft combined with northwesterly surface flow
will mean temperatures well below normal with chances of showers
as cold air aloft migrates through the region.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR is expected through the period outside of possible scattered
showers/thunderstorms mainly north of KPIT as a stalled frontal
boundary lifts back to the north.

.OUTLOOK...
Widespread restrictions are likely Friday and Friday night with
the encroachment of a cold front.

&&

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

&&

$$