247
FXUS61 KPBZ 251122
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
722 AM EDT Wed Jun 25 2025

.SYNOPSIS...
Hot and humid conditions will continue today. Shower and
thunderstorm chances will increase as a cold front approaches.
A few storms could be severe with damaging wind gusts and heavy
rain. The front will stall across the area through the weekend,
with daily shower and thunderstorm chances continuing.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- Extreme Heat Warning/ Heat Advisory in effect until 5pm
- Showers and thunderstorm chances increase through the day
- Marginal Risk for severe storms and locally heavy rainfall
---------------------------------------------------------------

Update...
Added POPs for isolated showers and thunderstorms early
this morning along an old outflow boundary from near Clarion to
eastern Allegheny county. This boundary should exit the forecast
area after sunrise.

Previous...
The persistent upper high will begin to drift southward today.
A shortwave trough, and an associated surface cold front, will
track along the northern periphery of the high by this
afternoon. Expect showers and thunderstorms to increase in
coverage through the day as this front and shortwave approach.
SB CAPE is progged to range from 1500-2500 j/kg by this
afternoon, with little shear in place. Dry mid level air will
enhance the DCAPE, with values around 1000 j/kg expected. This
will result in a damaging wind potential for storms that become
organized.

Weak flow aloft will also likely result in slow storm motion today.
In addition, PWATS from 1.7 to 1.9 will also result in a localized
heavy rainfall and flash flood potential, especially for areas that
see repeated thunderstorms. Will continue to include this potential
in the Hazardous Weather Outlook.

Hot and humid conditions will continue, at least until convection
fires this afternoon. Dropped a portion of the Heat Advisory for
areas along and north of I-80, and for the ridges of PA and WV,
where heat indices should stay in the 90s. Maintained the heat
headlines elsewhere, though did push the expiration time up to 5 pm,
when we should see cloud cover and shower/storms across the region.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
KEY MESSAGES:

- Locally Heavy Rainfall Through Friday
- Daily showers and thunderstorms, especially in the afternoon
  and evening
- Strong storms possible each afternoon and evening

----------------------------------------------------------------

Ongoing convection in the evening, along with the marginal
severe and heavy rain potential, should gradually wane as
instability slowly diminishes. A few showers or thunderstorm is
possible overnight with some lingering elevated instability, and
the front stalled across the region. Patchy fog and stratus is
expected, especially where partial clearing occurs, and where
rain fell during this afternoon.

The quasi-stationary front is expected to lift northward on
Thursday, as another shortwave tracks along the northern
periphery of the upper high. Expect showers and thunderstorms to
increase in coverage again, peaking in the afternoon and early
evening. The mid levels moisten some over what is expected to be
seen Wednesday, though enough dry air is in place to again
result in some wind gust potential with any more organized
storm. CAPE is progged to range from 1500-2000 j/kg by
afternoon, with little shear in weak flow aloft. An increasing
potential for locally heavy rain and flash flooding is expected.
Will monitor conditions over the next few days for any need of a
flood watch. HREF PWATS are progged at 1.6 to 1.8, with the weak
flow aloft resulting in slow storm motions.

Convection should again wane Thursday evening with the loss of
daytime heating and diurnal instability, and as the surface
front lifts northward, as surface low pressure tracks along the
front into Michigan.

A general lull in the activity is expected Friday morning,
before showers and storms increase again by afternoon as the
surface low tracks across the Lower Great Lakes and southern
Ontario. The low will pull a cold front back to the south,
approaching the Upper Ohio Valley region in the afternoon. More
organized storms are possible. The potential for gusty wind will
continue in some storms with dry mid level air enhancing the
DCAPE. PWATs are expected to lower somewhat on Friday, though
with relatively weak flow aloft a locally heavy rain/flood
potential will continue with slow storm movement. Convection
should again wane in the evening with the loss of diurnal
instability.

Very warm and humid conditions will continue through the period.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
KEY MESSAGES:

- Active weather continues with daily shower and thunderstorm
  chances into the start of next week
- Potential for storms and locally heavy rainfall through the
  period
-------------------------------------------------------------------

Model ensembles indicate westerly flow aloft across the Upper
Ohio Valley region through the weekend. Shortwaves embedded in
this flow will continue to result in daily showers and
thunderstorms, with the greatest coverage in the afternoon and
evening hours. Elevated PWATs will maintain a locally heavy
rainfall potential as well.

A deepening trough is then expected to track from the Upper
Midwest to the Great Lake and Upper Ohio Valley region early
next week. This will maintain showers and thunderstorms in the
forecast. The trough axis, and a surface cold front, is
currently progged for a Tuesday passage. A break from the active
pattern is expected after FROPA.

Temperatures are expected to continue to range from 5 to 10
degrees above average for much of the long term period.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
Weak shortwave movement that nudges the upper ridge south
combined with diurnal destabilization will allow isolated to
scattered thunderstorm development aft 18z today, with HREF
modeling favoring the I-70 corridor. The storm environment will
support storms that could produce 1-2"/hr rainfall rates that
quickly lower visibility to 1 mile or less while also generating
erratic gusty outflow winds that could exceed 30kts. Attempted
to provide some wind direction within tempo thunderstorm mention
based on broad atmospheric motion but vastly different
directions can occur.

Loss of diurnal heating should decrease convective activity
after 00z, but the moist/warm environment could allow for
isolated storms to persist or develop through the overnight
hours. Gradual clearing of convective cloud blow off through
Thursday morning may allow for strong radiational cooling that
leads to patchy low stratus/fog, favoring locations that
received higher rainfall totals during the afternoon.

Outlook...
Little pattern change is expected through Tuesday which means
that mainly diurnally driven scattered thunderstorms are
expected during this timeframe. Restrictions will be mainly
tethered to thunderstorm activity and patchy morning stratus/fog
that is dependent on overnight clearing and degree of daytime
saturation (i.e. amount of rainfall received the prior
afternoon).

&&

.CLIMATE...
Daily record high maximum (left) and daily record high minimum (right)
temperatures for Wednesday and Thursday are listed below.


Wednesday June 25th
Pittsburgh, PA:         98F (1988)              75F (1952)
Zanesville, OH:         101F (1988)             72F (1952)
Morgantown, WV:         94F (1921, 1952, 1988)  74F (1952)
Dubois, PA:             91F (1966)              67F (2000)
Wheeling, WV:           97F (1943)              75F (1952)
New Philadelphia, OH:   92F (1966, 2002, 2005)  68F (2013)

Thursday June 26th
Pittsburgh, PA:         95F (1966)              75F (1952)
Zanesville, OH:         97F (1952)              73F (1952)
Morgantown, WV:         96F (1952)              74F (1952)
Dubois, PA:             91F (1966)              66F (2000)
Wheeling, WV:           96F (1943, 1952)        73F (1952)
New Philadelphia, OH:   99F (1988)              71F (2022)

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Heat Advisory until 5 PM EDT this afternoon for PAZ013-022-031-
     077.
     Extreme Heat Warning until 5 PM EDT this afternoon for PAZ014-
     020-021-029-073-075.
OH...Heat Advisory until 5 PM EDT this afternoon for OHZ039>041-
     048>050-057>059-068-069.
WV...Heat Advisory until 5 PM EDT this afternoon for WVZ001>004-012-
     021-509-510.

&&

$$

SYNOPSIS...WM
NEAR TERM...WM
SHORT TERM...WM
LONG TERM...WM
AVIATION...Frazier
CLIMATE...