106
FXUS61 KPBZ 011100
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
700 AM EDT Tue Sep 1 2026

.WHAT HAS CHANGED...
A slight risk has been added for the forecast area for today
into tonight. A slight risk remains in effect for Wednesday.
Heat risk looks to be the greatest on Wednesday but storms and
cloud cover complicate that.

&&

.KEY MESSAGES...
1) Additional shower and thunderstorm chances at times through
late week, with some possibility for severe storms.

2) Heat and humidity build through mid week

&&

.DISCUSSION...
KEY MESSAGE 1...
The 500MB ridge over the central CONUS will shift east as
northwest flow sets up over the Great Lakes and into the Upper
Ohio Valley. This will set up a series of shortwaves to travel
southeast over the region the next few days. The timing of the
shortwaves over the next few days will be the main issue as hi-
res models and ensembles are not handling the setup very well
in the timing and placement.

There is a conditional potential for severe storms today. ML
CAPE increases to between 2000 and 3000 J/kg by late afternoon
and into the evening but consensus in the models suggests a more
overnight threat and MU CAPE aloft suggests a good 2000 to 3000
J/Kg CAPE overnight if the instability can be tapped into
during the overnight hours.

Wednesday appears to be a day where the threat will be more in
the late afternoon and evening. Current indications are the
ridge should begin to break down late Wednesday and Thursday, as
a shortwave and surface cold front approaching. The potential
for severe storms will also increase by Wednesday evening,
increasing again on Thursday as convection increases in diurnal
heating along the slow moving front. Increasing NW flow aloft
should result in increased shear and diurnal instability. The
potential continues for severe storms into Thursday. The latest
ML guidance indicates the increasing severe potential,
especially late Wednesday and Thursday.

KEY MESSAGE 2...
Rising 500mb heights with the building ridge should result in
warmer temperatures each day through mid week, with the heat
peaking Wednesday when the ridge is strongest across the Upper
Ohio Valley region. Most locations outside of the higher terrain
should reach the 85 to 90 degree range today, though there is a
continued potential for convection and/or patchy cloud cover
which could affect daytime highs. The heat should peak
Wednesday, as highs in the upper 80s to lower 90s for most
areas. The combination of heat and humidity should result in
heat index values in the mid to upper 90s Tuesday and Wednesday.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Influence of surface ridging and high pressure aloft favors VFR
through the TAF period. The only non-convectively driven
restriction development expected is near DUJ where moisture
convergence and subtle upslope WSW flow encourages mist and IFR
stratus near dawn Wednesday.

The main storm remains the potential for generally localized
showers and thunderstorms as weak shortwaves move across the
upper ridge. Most likely, terminals remain dry with any
shower/thunderstorm development occurring outside the airport
radius, if they form at all (scenario favored in TAFs). However,
the warm, humid environment could foster such storm that, if it
were to impact a terminal, could quickly reduce visibility in
heavy rain while creating gusty, erratic winds.

Outlook...
Shortwave movement along the northern periphery of the ridge
could create short periods through the week where
showers/thunderstorms may occur. Due to difficulties modeling
these features, timing/coverage of storm potential may be
difficult until 6-12 hours before arrival and cause larger-
than-normal fluctuations in TAF storm timing. Additionally,
storm environments may be conducive to gusty, erratic winds plus
heavy downpours that could contribute to restriction
development.

&&

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

&&

$$

DISCUSSION...Shallenberger
AVIATION...Frazier