600
FXUS61 KPBZ 271753
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
153 PM EDT Mon Jul 27 2026

.WHAT HAS CHANGED...
The highest potential for severe weather has shifted slightly
westward today into tonight, with a Slight Risk across NW PA
through E OH. A Marginal Risk remains across wrn PA and nrn WV.

&&

.KEY MESSAGES...
1) Showers and thunderstorms at times through tonight, with some
severe and locally heavy rain potential

2) Showers and thunderstorms continue into Tuesday, with
decreasing severe weather potential

3) Showers decreasing W-E Wednesday and Thursday, then mainly
dry and seasonable through Saturday

&&

.DISCUSSION...
KEY MESSAGE 1...
Convection was developing across the Great Lakes region early
this afternoon, and will continue to track southeastward. The
latest mesoanalysis shows increasing diurnal instability across
the region, with ML CAPE ranging from 1000-2000 j/kg. Capping
was observed on the 12Z PIT sounding just under 700mb, which
will likely initially limit convective potential across the area
early this afternoon. Some erosion of the cap is expected
through the day, though a warm layer remains around 700mb
through early this evening.

Expect scattered convection to develop across areas north of
I-70 this afternoon as convective temperatures are reached, and
as the cap slowly erodes. Additional showers and thunderstorms
could become focused along a lake breeze, and with outflow from
convection upstream. Some storms could contain damaging wind
gusts, with increasing shear and dry mid level air. The latest
day one outlook from the Storm Prediction Center maintained a
Slight Risk for severe storms across NW PA into ern OH, with a
Marginal Risk elsewhere.

Additional showers and thunderstorms are expected to cross the
Upper Ohio Valley region tonight ahead of an approaching
shortwave trough and surface cold front. A potential MCS could
clip some of the Ohio counties later this evening as well. The
most favorable instability (1500-2500 j/kg ML CAPE), and shear
(30-40kt) is expected to be across Ohio, with lesser values to
the east. This lines up well with the latest day one outlook
from SPC. The severe potential should wane somewhat overnight,
through there should be enough instability to maintain
thunderstorms. Locally heavy rainfall will be possible if any
training occurs, though the limited potential and uncertainty
precludes a flood watch at this time.

KEY MESSAGE 2...
Expect some ongoing convection and cloud cover Tuesday morning
as the cold front/shortwave continue to approach. Increasing
instability near and SE of the cold front should result in a
Marginal Risk of severe storms, mainly south of a DUJ-BTP-ZZV
line. The extent of any morning convection and cloud cover will
have an impact on the amount of instability, and resulting
severe weather potential through the day.

Showers and thunderstorms should begin to diminish by evening as
the front crosses and begins to exit the region, and as
instability decreases.

KEY MESSAGE 3...
The shortwave trough is progged to deepen into an upper low
across the NE CONUS by mid week. Wrap around moisture and lift
should result in shower chances continuing east of I-77 on
Wednesday, decreasing further from W-E on Thursday as the low
drifts eastward. Shortwave ridging is then progged to move
across the Upper Ohio Valley region later Thursday through
Saturday, with dry and seasonable weather expected. The next
chance for showers and thunderstorms is expected Saturday night
and Sunday with the next approaching shortwave trough.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
No major edits made to mentions of rain/thunder as hi-res
models haven`t changed much over recent runs. For this afternoon
and early evening, favored thunderstorm development mainly in
northwest PA (FKL/DUJ) off a lake breeze, with potential for
storms migrating/developing SE into western and SW PA with
resultant convective outflows.

Convective outlooks remain uncertain after 22z due to their
reliance on the path/effects of upstream thunderstorms or
mesoscale convective systems moving from the western Great Lakes
into the Ohio Valley. Maintained a similar trend as recent TAF
cycles, which assumed MCS activity remains west of the region
but included an uptick in storm development later in the night
(near/after 06z) as an outflow boundary and mid-level shortwave
move across the local area through early Tuesday morning.

Outlook...
Moisture convergence ahead of an incoming trough/surface cold
front may result in MVFR to locally IFR conditions even outside
of convection Tuesday morning. Thunderstorms are likely
along/ahead of the boundary with potential for showers to linger
in the post-frontal environment due cold NW flow aloft
maintaining some buoyancy.

High pressure builds through the mid-week period to increase the
duration of VFR periods with dry weather, with any restrictions
mainly occurring during the morning hours.

&&

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

&&

$$

DISCUSSION...WM
AVIATION...Cermak