Area Forecast Discussion
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FXUS61 KPBZ 260800

Area Forecast Discussion
National Weather Service Pittsburgh PA
400 AM EDT Fri Apr 26 2019

Unsettled period through much of the weekend as a series of low
pressure systems roll through the Ohio Valley.


Deepening surface low will spin northward this morning and the
trailing cold front will quickly move across Ohio after dawn, and
through the rest of the region by early afternoon. Showers and storms
will blossom ahead of the front, but with the lack of upper level
support, and the time of day, would think that any convection will
remain below severe levels and be mainly situated right along the
surface boundary. Heavy downpours are possible with any storm as deep
moisture will overspread the region ahead of the front.

Entire surface system will get a nice push from the digging upper
trough which will shift into eastern Ohio by the afternoon.
Precipitation will decrease from west to east behind the front,
though post-frontal showers will linger through the evening hours
until the trough exits.

A tightening surface pressure gradient ahead of the front and
pressure rises behind it, will support gusty winds today.


Rather impressive post-frontal cold advection will yield chilly
temperatures tonight and Saturday. Would also expect to see a
stratocu deck cover at least the eastern half of the region in the
cold air regime. The lower clouds should remain over a portion of the
region through Saturday morning, until weak warm air advection takes
over and shoves the cold pool aloft to the northeast.

Any precipitation Friday night/Saturday morning would likely be in
close correlation with the coldest air aloft and along the ridges due
to a good upslope flow. The atmosphere across the far north looks
cold enough to support snow flakes, but with lowering inversions and
the loss of upper level moisture, it will be difficult to form

Adequate mixing at low levels will support the continued threat for
gusty wind on Saturday.

A progressive shortwave trough will increase precipitation chances
once again late Saturday/early Sunday, with building high pressure
progged thereafter. Another shot of cold air, behind the shortwave,
will yield another chilly day on Sunday.


Rising heights and building high pressure will support a dry and
warming trend early in the week, with later-period precipitation
chances influenced by upper disturbances embedded within a
predominately zonal flow.


Deterioration to MVFR in rain is expected overnight as low pressure
approaches and pulls a warm front N across the region. Further
deterioration to IFR is expected Friday morning as the sfc low and
its associated cold front crosses the region.

A period of LLWS is expected overnight with an approaching low level
jet. The jet should exit by sunrise ending this potential. Gusty W
wind of 25-30kt is expected after the Friday morning/early aftn FROPA
with a tight pressure gradient, cold air advection, and mixing.

A return to VFR is expected with post-frontal clearing by approx 00z

.Outlook...Restriction potential returns with low pressure Sat
night/Sun and again late Mon/Tue.




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