789
FXUS61 KPBZ 212330
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
730 PM EDT Fri Aug 21 2026

.WHAT HAS CHANGED...
The forecast messaging remains generally unchanged. The aviation
discussion has been updated for the 00z TAF cycle.

&&

.KEY MESSAGES...
1) A marginal damaging wind and hail threat may develop with
thunderstorms Saturday afternoon/evening, followed by a cold
front that brings pleasant weather to the area early next week.

&&

.DISCUSSION...
KEY MESSAGE 1...
The main focus remains on a shortwave that acts to deepen upper
troughing over the region Saturday into Sunday morning while
driving a cold front west to east through the region. Hi-res
ensembles are beginning to suggest upstream convection tonight
could result in some sort of decaying convective system
entering our eastern Ohio counties (roughly along/west of the
I-77 corridor) early to mid Saturday morning. Convective-
allowing models have that feature weakening with time, but they
also suggest upwards of 1000-1500 J/kg MUCAPE already
developing ahead of it, thanks to mostly clear skies and a mid-
to-late August sun angle. It`s not uncommon for CAMs to weaken
nocturnal/morning convection too quickly, especially in the
presence of marginal MUCAPE and shear. If that ends up the case,
it`s possible that instead of convective initiation waiting
until late afternoon and evening hours, we see an outflow
boundary triggering thunderstorm development during late morning
and early afternoon as it tracks eastward across the northern
WV panhandle and into western PA.

Assuming the morning convection does decay as CAMs suggest,
confidence is fairly high that by mid to late afternoon the
local storm environment could see upwards of 1500-2500 J/kg
CAPE, around 850 J/kg DCAPE, and 20-30 knots of deep-layer shear
that would be conducive to localized downbursts and perhaps
some weak organization into multicell clusters, both of which
support a damaging wind threat. Dry air aloft will also support
a marginal severe hail threat, though significant/giant hail
still appears unlikely.

Thunderstorm activity should taper off after dark with the loss
of daytime heating, followed by the cold front moving through
and exiting the area by early Sunday morning. Cold core
processes underneath the deeper trough behind the cold front
will keep lake-enhanced shower and low probability thunderstorm
chances in the forecast on Sunday, with the greatest focus
along the ridges and north of Pittsburgh. Thereafter, dry
weather and seasonably cool temperatures settle in through
Monday until building high pressure underneath height rises
fosters a warming trend back to near-seasonal levels Tuesday.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
Localized fog, favoring river valleys, may develop again
Saturday morning with models favoring areas south and west of
Pittsburgh. Confidence in more than brief impact is low, so have
continued with TEMPO groups to cover this at each terminal.

Scattered showers and thunderstorms are expected Saturday
afternoon with an approaching cold front. A few of these storms
could bring damaging wind gusts. Rain coverage generally
decreases after sunset 00z, but isolated showers may linger into
the overnight. Ceilings are expected to lower into IFR range
overnight before improvement through Sunday.

Outlook... Additional rain/restriction chances linger through
Sunday evening thanks to cooler NW flow and lake moisture
enhancement.

&&

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

&&

$$

DISCUSSION...Cermak/Frazier
AVIATION...Rackley