Area Forecast Discussion
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FXUS61 KPBZ 250731

Area Forecast Discussion
National Weather Service Pittsburgh PA
331 AM EDT Tue Apr 25 2017

Low pressure tracking along the East Coast should result in
periodic rain chances mainly east of I-79 early in the week.
Dry and warm weather is expected with mid-week high pressure.


At this writing, light rain is mainly confined to areas south
and east of Pittsburgh. Winds along/in the western lee of the
ridges have remained mostly around or under 30 MPH. Will
continue to monitor, but the risk of higher gusts appears to be
decreasing. Upper level low pressure continues to spin up the
Atlantic seaboard today. Easterly flow along the periphery of
this system will continue to pump Atlantic moisture mainly into
the ridges for most of the day, and as such have continued with
the higher PoPs in the east. Early on though, models have been
consistent in showing a short period of low- level convergence
that should generate at least scattered showers over even the
western CWA this morning. Have thus extended chance values all
the way to ZZV. This support breaks down by midday, with the
continued ridge focus thereafter. Southeast Ohio will see the
most sun today on the outer edge of the cloud shield.
Temperatures will be above normal here, and closer to
climatology further east.

The upper low takes on more of a northeastward component this
afternoon and tonight in response to increased ridging over the
Ohio Valley. This will lead to a slow decrease in rain chances,
with the last straggling showers moving east overnight. Despite
decreasing clouds, temperatures will remain above normal with a
lack of cold advection.


Quiet weather is anticipated for Wednesday and Wednesday night
with surface high pressure and the passage of a mid-level ridge.
Rising heights and flow turning southwest point to rising
temperatures, with all locations rising well above normal, many
reaching or exceeding 80 degrees Wednesday afternoon.

Even warmer temperatures are expected Thursday afternoon as
strong southwest flow should efficiently mix down +18C 850 mb
temperatures to get many locations into the mid 80s. However,
clouds will be on the increase as a shortwave trough rotates
from the upper Midwest into the Great Lakes, pushing a boundary
towards the area. Best support for precipitation will lies from
Pittsburgh on northwest, where likely PoPs were maintained.
Instability and shear levels point to a few strong storms, but
not expecting a widespread severe threat at this time.


Surface high pressure in broad SW flow aloft may provide a
relatively dry Friday with cooler but still above-normal
temperatures. Rain chances increase into the weekend as a trough
deepens over the Rockies and the Plains, with embedded
shortwaves providing some rounds of rainfall. Rising heights
will lead to a slow warmup back into the 80s by Sunday. The
trough may eject Sunday night/Monday and push a fairly strong
cold front our way by Monday. With a negative-tilted trough and
and moist SW flow, we will need to monitor the severe risk from
this system over the next several days. Dry and cooler weather
follows this system.


VFR conditions through most of the day as mid-deck shield will
continue to blanket the region. The exception will be at DUJ,
which will see lower moisture spill over the ridges in easterly
flow, causing a reduction to MVFR as dawn approaches. LBE will
also see MVFR cigs by late morning. Models are indicating
another round of light showers crossing the area late tonight
and during the morning hours.

Light easterly winds will increase later this morning, with
gusts of 20 to 25kts possible.

By late in the forecast period, all ports are expected to see
MVFR restrictions, as the continued easterly flow pushes low-
level moisture further west.

The next chance for general restrictions is expected with late
week low pressure.




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