984
FXUS61 KPBZ 160004
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
804 PM EDT Wed Jul 15 2026

.WHAT HAS CHANGED...
Expiration of the Heat Advisory and update for 00z TAFs.

&&

.KEY MESSAGES...
1) Above average temperatures and smoke persist late-week.

2) Storm chances, along with severe and flooding risks, return
into the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...
Thursday, there is high confidence that near-surface smoke
concentrations will increase from wildfires originating in
southern Ontario and northern Minnesota. Exact concentrations of
smoke will depend on the exact intensity of upstream fires, but
current thoughts show moderate air quality degradations, though
not as severe as the smoke event from June 2023. Smoke will
progress in from the north, with concentrations rising for the
I-80 corridor at sunrise; southwest PA, east OH, and the
northern WV panhandle mid-morning; and northern West Virginia in
the early afternoon. In coordination with OH, PA, and WV
Departments of Environmental Protection, Air Quality Alerts are
in place for Thursday. Refer to your state`s department for
more information.

Smoke may actually knock 2-3 degrees off forecast high
temperatures, slightly reducing heat risk from the day prior.
Temperatures are expected to fall back to near-normal for the
weekend. Near surface smoke is expected to linger until more
flow or rain clears it out. At this point, modeling has it
through at least Friday, but bouts may last through the weekend.

KEY MESSAGE 2...
The ridge breakdown will occur during the Friday and into
Saturday period. This will tend towards a pattern of western
ridging and eastern troughing, along with cooling temperatures
into Saturday, Sunday, and early next week.

Ensemble clustering is in good agreement in the general flow
through the weekend. The main uncertainty will be 1) the
presence of a shortwave trough late Friday and 2) the timing and
position of a shortwave trough Saturday.

GFS dominated ensembles show a shortwave passage late Friday
that would result in heightened convective coverage Friday
afternoon in low cape environment with most flow in the mid-
levels. This could result in some convection, but relatively
low severe chances with DCAPE less than 600. Mid-level flow
might also be progressive enough to mitigate flood risk unless
training exists. All this to say, that this point it is
generally more likely in low to no convective coverage at all,
with Canadian and Euro based ensembles showing a lack of a
shortwave altogether.

Severe and flood chances now definitively maximize on Saturday
with higher confidence of a shortwave passage. In the scenario
where the shortwave is stronger, much of the threat may be
focused to regions southwest of Pittsburgh (GFS scenario), with
severe chances relativity higher and flood risk slightly lower.
In the event that the shortwave is weaker, the threat may be
focused near and northeast of Pittsburgh with severe chances
relatively lower, but flooding risk higher. The reason for
this: stronger flow and forcing aloft is more favorable for
severe convection but worse for flooding via training storms
(and vise versa). Because of this, theoretically all threats are
on the table but certainty may increase as trough intensity is
refined.

As for flood risk, LREF 50th percentile PWATS will be >90th
percentile, and convection may be boundary parallel as it moves
from the northwest to southeast in a weaker or multi-axial
trough passage. Model soundings show long, skinny CAPE. There
are some particularly high-QPF analogs in similar patterns, and
NBM 90th percentile to max QPF shows 2-5" is certainly possible
somewhere.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR continues to open the TAF period. With lessening heating,
winds are beginning to subside. Scattered cirrus likely continue
overnight and there could be some lower end chances of fog,
especially in the southern river valleys. Wildfire smoke could
locally provide increased chances for fog formation.

Smoke effects begin to increase late tonight spreading from
north to south and thickening through the day. Smoke impacts
likely begin as MVFR restrictions to VIS in HZ. As the lobe of
smoke more directly sits across the area, restrictions will
increase and stretches of IFR are possible especially for
FKL/DUJ. In the thickest smoke, LIFR could be possible as noted
upstream today in airports currently experiencing smoke, with
observations as low as 1/2SM in Michigan.

Outlook...
High pressure maintains light winds and few clouds through
Friday. Restrictions will likely come in the way of smoke
reductions to visibility which will continue through Friday
before lessening this weekend. Thunderstorm chances return late
Friday into the weekend as upper level shortwaves traverse the
region.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Air Quality Alert from midnight tonight to midnight EDT
     Thursday night for PAZ008-009-013-015-016-031.
OH...Air Quality Alert from 7 AM Thursday to midnight EDT Thursday
     night for OHZ039>041-048>050-057>059-068-069.
WV...Air Quality Alert from 7 AM Thursday to midnight EDT Thursday
     night for WVZ001>004.

&&

$$

DISCUSSION...MLB/Milcarek
AVIATION...AK