600
FXUS61 KPBZ 151056
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
656 AM EDT Tue Sep 15 2026

.WHAT HAS CHANGED...
No significant changes made to the forecast.

&&

.KEY MESSAGES...
1) Rain and storm chances increase late Wednesday into early
Friday, highest for the day on Thursday. Low, but non-zero flood
and severe weather risks are forecast.

2) A more unsettled weather pattern returns for the weekend with
more rain chances and more seasonable temperatures. Uncertainty
in the weather pattern increases into next week.

&&

.DISCUSSION...
KEY MESSAGE 1...
A cold front is expected to sag down into the Great Lakes region
Wednesday into Friday. This will generally bring ascent and a
saturating trend to the atmospheric column. Rain chances
increase throughout the day on Wednesday. A few showers are
possible in the morning (highest north of I-80) in weak ascent,
but highest chances work their way into the I-80 corridor and
portions on northeast Ohio late Wednesday with models hinting at
a stronger pre-frontal trough in mid-level ascent, and better
timing to utilize daytime destabilization. At this moment,
median SBCAPE is only a few hundred Joules, with sfc-6km shear
at 20-25kts and DCAPE not particularly high at 400. This alludes
to low severe potential, however PWATS pushing 1.8-2.0 inches
allude to flood threats, which will likely only be realized in
the event of training.

A slow moving frontal passage into Thursday will bring higher
chancres of rain, overall. Shear remains non-dissimilar from
the day prior, though ensembles indicate an uptick in
instability (1000-1500 J/kg) and DCAPE (600-900). PWATs at this
point will be pushing 2.0-2.1 inches, which would be an all-time
record for that calendar date. Though flow will generally be
progressive, with a slow moving front, we will have to monitor
for training potential in storms. Overall, the severe risk
remains very low and the flood risk remains low, but increasing
some. Rain chances persist through Thursday night, generally
moving south of I-70 by Friday morning as the front sags. With
probabilistic guidance dominated by global model output this
far, we will have to wait for convective models to start being
ingested to better estimate high-end rain potential.


KEY MESSAGE 2...
There is fairly high confidence that the region will sit on the
northeast side of a east-central CONUS ridge into the weekend,
which generally brings south-southwest surface flow and west-
northwest flow aloft. This will keep more moisture, allow for
shortwave passage potential and, generally, a pattern of
moisture overrunning. This favors wet conditions Saturday
through Monday in showers/storms with more seasonable
temperatures. This confidence breaks down beyond Monday as the
pattern is more bi- modal. Either a front pushes south and
brings in cooler and drier conditions for next week, or it
remains wetter, warmer, and more unsettled should the upper flow
not change much.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
VFR with lighter east to southeast wind under the influence of
high pressure is favored through the TAF period. Though a few
afternoon CU may develop, most passing cloud cover will be
scattered cirrus with periods of mid-level decks closer to
FKL/DUJ.

Low probability shower chances (that could result in a period of
restrictions) exist near/north of FKL/DUJ after 06z tonight but
are too low for mention at this time.

Outlook...
Gradual shortwave progression over the top of the current upper
level ridge will increase shower and thunderstorm chances along
with resultant restrictions Wednesday night into Thursday.

Brief passing high pressure Friday offers quieter weather before
a potentially active pattern develops Saturday into next early
next week.

&&

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

&&

$$

DISCUSSION...Milcarek
AVIATION...Frazier