Area Forecast Discussion
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FXUS61 KPBZ 270524 AAC

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
124 AM EDT Thu Oct 27 2016

Low pressure will bring rain to the region today. Dry and cool
weather returns Friday. Warmer but unsettled weather is
anticipated for the weekend.


PoPs have been updated and slowed for the overnight period. A
persistent low-level easterly flow is keeping the air near the
surface relatively dry. The drier atmosphere shows up quite well
on current observations, as surface dewpoints remain in the upper
20s to mid to upper 30s at most locations. This in turn is causing
showers over Ohio to dissipate as they move eastward toward the
area. Expect the lower levels to final moisten late tonight as the
flow shifts to the south-southeast. Temperatures were also
updated with a blend of hires guidance.

Categorical PoPs were maintained over the north and east, where
sufficient lift and moisture are expected to reside. The front is
slated to exit eastern locales late this afternoon and push the
boundary induced showers to the east.

Temperatures will be normal today.


Cold advection behind the departing low pressure will be brief,
but shower chances should continue through tonight, mainly over
the north and east. Some snow may mix in as well, especially
north of I-80 and in the high terrain. Expect any precipitation to
end late tonight as inversions lower.

High pressure will settle over the Ohio Valley Friday, with
decreasing cloud cover as warm air advection ensures.

With the progressive upper level pattern, another system is
expected to approach late on Saturday. However, models are still
showing little agreement on how much impact, precipitation wise,
this next system will have on the area. Felt a model blend was
best for the Saturday forecast. Strong warm advection Saturday,
will allow for temperatures 5-10 degrees above seasonal averages.


The models are in relatively good agreement for the start of the
long term, with another shortwave expected to cross along a slow
moving boundary over the Ohio Valley on Sunday. After this time,
the models evolve the next low pressure system over the northern
Plain/Canadian border differently, so a blend of model guidance
was used. Overall, expect temperatures to remain at or just
slightly above seasonal averages through the period.


Main concern overnight will be potential for LLWS as surface winds
have decoupled from stronger winds already being observed via
RAOB/VWP/MDCRS observations. LLWS potential will continue into
morning. The potential will lessen somewhat as surface winds
increase this morning.

CIGS/VIS will remain VFR the remainder of the evening with MVFR
conditions developing after midnight as low pressure approaches
from the west.

Areas north of Pittsburgh will likely see IFR by sunrise and
continue for much of the day until winds shift and drier air moves
in mid/late afternoon.

VFR returns by Friday. More restrictions are possible this
weekend with another front.




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