Area Forecast Discussion

Pittsburgh, PA

Forecast Discussion for PBZ NWS Office
976
FXUS61 KPBZ 252317
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
617 PM EST Wed Nov 25 2020

.SYNOPSIS...
Rain will be widespread this evening and continue into Thursday
morning. Temperatures remain above normal through Thursday, before a
dry and seasonable stretch.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A mature and weakening low pressure system that is sustained by jet
support and vorticity advection will provide the ascent for
widespread rain tonight, before propagating east Thursday morning.
With consistent rain and cloud cover, temperature will remain mild
overnight, above calculated normals.

With a quick and steady progression, moderate to heavy showers
aren`t likely to cause any flooding.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
Rain will end on Thursday followed by a seasonably warm afternoon as
shortwave ridging ensues in response to the advance of another cntrl
CONUS trough.

A weak shortwave trough will cross the area Friday morning. This
will provide brief cold advection which will work to keep cloud
cover over the region and cool daytime highs by a degree or two.
Models are hinting that a passing shower is possible as the colder
air aloft moves through. However, building high pressure will combat
shower development, so for now will leave Friday dry.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A dry stretch is anticipated before a robust low pressure system
will be monitored through the weekend as polar air intrusion and
strong large scale dynamics may collide and provide the chance for
rain or snow early next week.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...

A break in rain showers is expected as drier air advances into the
region from central Ohio. VFR conditions will continue for the next 6
hours as warm air prevails under southerly flow.

Ceilings will drop as a cold front, currently in easter Indiana,
moves east. Expect rain showers along the frontal boundary, vis may
drop briefly to 4SM/5SM. All sites will obs MVFR cigs near or just
after 12Z (IFR at DUJ/FKL). With a strong vertical wind profile, wind
shear too will linger overnight and into early morning hours,
especially south of BVI.

Light rain should then taper into more showery precipitation after
dawn as lapse rates steepen in the wake of the departing
disturbance, eventually diminishing in a lowering subsidence
inversion. Despite building high pressure, trapped moisture within
the aforementioned inversion should maintain MVFR/IFR cigs through
the remainder of the TAF period.

.Outlook...
Cig restrictions are likely for some sites through Friday as winds
shift from the NW and lake moisture advances into western PA.

&&

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

&&

$$

NWS PBZ Office Area Forecast Discussion