392
FXUS61 KPBZ 091335
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
935 AM EDT Thu May 9 2024

.SYNOPSIS...
Showers return today along with possible thunderstorms south of
Pittsburgh. Unsettled weather and cooler temperatures will
continue through Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:

- A frontal boundary will serve as a point of initiation for
  showers and thunderstorms through the day.
-------------------------------------------------------------------

A surface low pressure system will begin to develop to the
south along the Mid Appalachian Range and slowly slide east. As
this feature slides east, further deepening of the low will
assist increase south flow and thus more moisture advection
adding to an overrunning setup into eastern OH and northern WV
and eventually into southwest PA. This will include a flood
threat this afternoon and evening along with a marginal severe
threat as a shortwave crosses the Upper OH Valley during the
evening. Based on instability, the threat still appears to be
minimal, but with at least 500 to 700 J/Kg for the 20Z to 00Z
timeframe and roughly 50 knots of shear or more, there will be a
chance for strong to severe storms. The flood threat will
depend on where the heaviest axis of rainfall sets up but with
the NBM DESI probs showing 30% to 50% prob of greater than an
inch for the northern WV and southern SW PA counties, it does
seem to once again become a dual threat heading through tonight.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Showers/storms continue into Friday and Saturday.
- Ensembles suggest a wet pattern into the weekend.

-------------------------------------------------------------------

The low pushing east will be slowed by surface high pressure
over the east coast. This will allow enough forcing in the area
to keep showers and possibly a few thunderstorms in the area for
Friday. The low will eventually exit by Friday evening but a few
showers are expected to remain given a return to northwest flow
owing to a slight upslope component and lingering gradient.

By Friday night into Saturday, another fast moving shortwave
dives southeast in northwest flow bringing another round of
showers to the area. Overall, a rather damp weekend is on tap.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
KEY MESSAGES:

- Cooler temperatures arrive by late week with highs in the 60s
  this weekend.
-------------------------------------------------------------------

The trough that brought some showers and a few thunderstorms
will continue into Saturday night as the main axis of the
trough begins to exit the area by Sunday morning. However, given
the return to northwest flow behind the trough and a lingering
weak shortwave trough behind the departed front will keep a
chance of showers and possibly a thunderstorm through the day on
Sunday. By Monday, the models suggest a brief break in the
pattern suggesting a shortwave ridge passing through before the
next disturbance. This will be evident as the warm front sets up
across the northern portion of the forecast area by Monday
afternoon.

The low further develops as it shifts east and the main trough
axis crosses southern OH keeping unsettled weather across the
area through the middle of next week.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
MVFR cig restrictions with rain will return from the south
after today as a sfc low passes south of the region. Any TSRA later
in the afternoon should be limited to ports south of KPIT.

It becomes increasingly likely that cigs will lower to IFR/LIFR
from the south after 00Z with lingering moisture and cooler
conditions behind a cold front.

.Outlook...
Restrictions will likely continue through Friday afternoon with
lingering low-level moisture and cold advection.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...Shallenberger
SHORT TERM...Shallenberger
LONG TERM...Shallenberger
AVIATION...88