421
FXUS61 KPBZ 150633
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
233 AM EDT Wed Jul 15 2026

.WHAT HAS CHANGED...
Added smoke to the grids for late this afternoon and into
tonight to include Thursday.

&&

.KEY MESSAGES...
1) Temperatures and heat indices maximize for most Wednesday
with major heat risk likely.

2) Wildfire smoke aloft returns to the area for the beginning of
the forecast period.

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

&&

.DISCUSSION...
KEY MESSAGE 1...
The ridge will be in place over the eastern CONUS today, but
will begin to shift back west. This will keep dry conditions in
place. With northwest flow aloft beginning to take shape, this
will keep the higher dew points out of the region. Thus the Heat
Risk for today will be marginal Heat Advisory values. Values of
100 to 102 are still expected but just confined to the urban
areas of the forecast area. The northwest flow will begin to
usher in smoke to the region by the afternoon and into the
evening.

Thursday, smoke concentrations may be higher, challenging
continued temperatures above 90F, save regions south of US-22
where major heat risk may linger. This will also correlate to
the beginning of the ridge breakdown.

KEY MESSAGE 2...
The aforementioned smoke that HRRR is picking up on is mostly
from wildfires originating in southern Ontario and northern
Minnesota. Exact concentrations of smoke will depend on the
exact intensity of upstream fires. Models show prolific smoke
release given the continued hot/dry conditions.

An initial push of smoke today is expected to remain mostly
aloft and result in a milky/hazy appearance overhead. The main
wave of smoke today is forecast to pass to the south tomorrow,
before wrapping back into the more dense smoke advecting down
from Ontario Wednesday night. This round of smoke may bring
some more near surface smoke that could pose impacts to near
surface air- quality into late Wednesday and early Thursday.
Continued instances of smoke appear likely into the weekend with
little change in mid- level wind direction.

KEY MESSAGE 3...
As with most ridge breakdowns, there will also come a threat for
organized storm formation. Uncertainty with timing and intensity
is still now tied mostly to an infringing Pacific low rejoining
the flow as a shortwave. Once this does so (over the next 24
hours), it`ll become easier to resolve the timing and location
of storms into Friday and Saturday. A faster rejoining of this
would lead to a Friday arrival (lower probability), and a slower
rejoining would lead to a Saturday arrival (higher
probability). If the eastern trough amplitude is towards the
higher end, QPF totals may be towards the higher end of the
distribution and displaced into the northern Ohio Valley,
whereby, a lower trough amplitude would mean perhaps slightly
lower QPF potential and displaced into northern Pennsylvania.

Machine learning carries generally a 5% to 15% chance of severe
weather within 25 miles of a point when and where the threat
maximizes for now. With LREF 50th percentile DCAPE near 600 to
900, a marginal downburst threat is possible, but with mean
500mb flow of 30kts to 50kts, organized convection is certainly
possible. Curved low hodographs will also allude to the
potential for discrete or embedded tornado threats.

Another thing that will need to be monitored, maybe even more
so, is hydrological concerns. LREF 50th percentile PWATS will be
>90th percentile, and convection may be boundary parallel as it
moves from the northwest to southeast. 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 /06Z WEDNESDAY THROUGH SUNDAY/...
High pressure will remain in place across the forecast area.
This will keep dry conditions in place for another TAF period.
Expect some haze to develop today along with some smoke but
mainly north of I-70. Winds are expected to be out of the
southwest up to 10 knots through the day. Some cu is expected at
about 6 KFT with some passing cirrus with traces of smoke in it.
Overall, VFR forecast is expected with the exception of an
instance of fog in the morning.

Outlook... High pressure favors VFR through at least Thursday,
with only low probabilities for river valley fog near dawn. Due
to a dense area of smoke from wildfires in northern Minnesota
and western Ontario, it is possible for MVFR visibility
restrictions on Thursday. Confidence in these impacts is
increasing as upstream airports today feature haze and smoke VIS
reductions.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory from noon today to 8 PM EDT this evening for
     PAZ007-008-013>015-020>022-029-031-073-075-077.
OH...Heat Advisory from noon today to 8 PM EDT this evening for
     OHZ039>041-048>050-057>059-068-069.
WV...Heat Advisory from noon today to 8 PM EDT this evening for
     WVZ001>004-012-021-509.

&&

$$

DISCUSSION...Milcarek/Shallenberger
AVIATION...Shallenberger