Area Forecast Discussion
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FXUS61 KPBZ 180521 AAC

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
121 AM EDT Fri Aug 18 2017

Rain chance will continue through much of the day. The risk
will return again Saturday afternoon. Temperatures will stay
warm through the weekend.


First shortwave is east of the area, however trough axis remains
situated over the southern reaches of my forecast area. Another
wave is expected to move eastward overnight, reaching Western
Pennsylvania around dawn. Will need to keep in the mention of
showers or storms for the rest of the night on the southern
flank of this wave. No real change in the atmosphere is expected
as temperatures overnight remain warm and conditions humid.

Main trough axis will slowly drift eastward this morning as a
surface cold front moves across Lake Erie. With this area of
large scale ascension still looming and with low level moisture
continuing to feed into it, will need to keep PoPs in the
vicinity of the upper level wave, mainly over the southeastern
quadrant of the forecast area. Surface boundary looks to catch
up to the exiting trough this afternoon, which will provide an
additional eastward push of the moisture. To the west of the
axis, a decrease in cloud cover is expected, as drier and
cooler air drives to the southeast.


Dry and cooler tonight.

The next shortwave trough arrives Saturday afternoon. It
appears another surface boundary will cross the area just ahead
of the upper level energy, so would expect showers and storms to
redevelop as the system passes through.

Surface high builds in on Sunday as the flow aloft becomes


Broad high pressure will keep conditions dry Monday into Tuesday
before another cold front brings a chance of rain back to the
forecast for late Tuesday into Wednesday.


Weakening cold frontal convection is near KPIT as of 01z with an
attendant cold front. As second area of low pressure along the
front should allow it to buckle back northward over the next
several hours, with showers redeveloping around KZZV and
spreading NE from there. With ample rain continuing overnight,
as well as an already damp boundary layer, stratus will become
common overnight with nominal visibility restrictions.

Restrictions are possible with another passing disturbance




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