096
FXUS61 KPBZ 131743
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
143 PM EDT Wed Aug 13 2025

.SYNOPSIS...
Showers and thunderstorms are expected today and tonight as a cold
front crosses the region. The front will slowly exit on Thursday.
Mainly dry weather is then expected Thursday night through
Saturday as high pressure builds in.

&&

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

- Showers and thunderstorms today
- Locally heavy downpours possible
---------------------------------------------------------------

A lead shortwave trough that induced morning showers and storms
has largely vacated the region, but destabilization in its wake
and ahead of a second trough is ongoing. Showers/storms are
developing along the Ohio shore of Lake Erie within a lake-
breeze convergence zone, as well as more broadly in ern Ohio,
possibly along residual outflow from morning storms. Coverage of
showers and storms ought to increase quite a bit late today as a
cold front nears.

PWAT remains high, and buoyancy on the weaker side, suggesting
potential for localized heavy rain with any vigorous updrafts,
but storm movement also is non-trivial, which means heavy rain
ought not to linger from any one storm. However, storm
interactions within the increasing coverage area still will
support localized flash flooding despite the storm movement.
With little predictability in where such interactions might
occur, and the overall limited potential, no flash flood watch
appears necessary at this time. The threat has been highlighted
in the HWO and will otherwise be handled with mesoscale
messaging.

&&

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

- A few lingering showers/storm Thursday south of I-80
- Generally dry Thursday night through Friday night
----------------------------------------------------------------

The overnight trough axis will influence the region residually
Thu morning, potentially maintaining showers after sunrise. But
a high-confidence upper-level pattern is evident as shortwave
ridging builds into the nern CONUS and the sern ridge develops
nwwd into the MS valley. The net result during Thu-Fri will be
increasing influence of high pressure and limited risk of
storms.

If any storms do develop, they are most likely to occur within
terrain-induced convergence axes in the ridge zones of WV/PA
during the typical convective diurnal cycle.

With a transitioning pattern and generally clear overnight sky,
heat is not expected to be excessive, with maxima/minima near
normal in the upper 80s/low-mid 60s.

&&

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

- Dry and hot for areas outside of the ridges Saturday
- Shower and thunderstorm chances return Sunday
- Mainly dry and hot Monday
- Showers and thunderstorm possible Tuesday and Wednesday
-------------------------------------------------------------------

A relatively high-predictability pattern is anticipated for the
weekend, as an upper-level ridge builds nwd into the Midwest
while a strong low pressure center remains situated over far nrn
Canada. Between the two extrema, a shortwave trough is expected
to advance across Ontario, with variance in its intensity/poleward
positioning driving uncertainty.

On Sat, this axis is wholly predicted to avoid influencing the
Upper Ohio Valley, with any storm potential tied to terrain-
induced convergence lines in the ridge areas.

On Sun, if the trough axis position develops farther south as
some ensemble members suggest, there may be sufficient ascent on
Sun to support broader storm coverage, especially in the I-80
corridor, where enhanced convergence could exist along a frontal
zone.

Either way, above-average heat (near or above 90F) will return
for the weekend with high confidence. Given potential for higher
PWAT but also greater uncertainty in the degree of dry air
aloft during the weekend, it is unclear at this time whether a
notable risk for flash flooding or severe storms exists. These
concerns will be monitored as confidence in the atmospheric
ingredients increases closer to the weekend.

The broad pattern remains higher-confidence thru early next
week, with a ridge in the wrn CONUS and a trough over ern
Canada. The devil is in the details, though, as there also
remains considerable variance in cluster analysis of the pattern
amplitude and strength.

The net result of this variance suggests that the associated sfc
high pressure to the north of the Ohio Valley has considerable
east/west positioning difference among the ensemble membership,
and therefore makes wind direction/speed prediction difficult,
especially Mon/Tue. Any shower/storm chances during this time
again likely would be tied to terrain-induced convergence lines
along the ridges.

By Wed, the possible approach of another frontal zone into a
warm/moist airmass could support storms.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Many of our ports are coming up now with our first wave of activity
dying down. Another batch of storms is firing near ZZV at this time
and will likely just be VCTS for ZZV but could impact MGW again in a
couple hours. These storms could once again bring reduced VIS in
heavy rain as already seen at MGW.

We are beginning to see a couple of signs of the next round of
storms getting going across Cleveland`s area as the front slowly
moves forward. Coverage of these storms remains scattered but each
storm can bring localized reductions in CIGs/VIS and can bring gusty
winds. The scattered nature of these storms has been captured in
PROB30s across the region later today. Confidence in occurrence
remains far higher than location at this time and thus PROB30s have
been held and TEMPOs have not been used.

Stayed in line with keeping MVFR CIGs largely tied to convection. By
the evening, as convection settles down with the loss of daytime
heating, CIGs should become widespread VFR with higher confidence.
However, this period may be rather short. MVFR or IFR CIGs look
likely overnight with fog possible at a number of ports. At this
time TEMPOs for fog have been included in FKL/DUJ/MGW. If needed we
can expand these in future updates. Degraded CIGs are expected to
begin to scatter by tomorrow afternoon.

Outlook... Thursday, a chance for showers and associated
restrictions return as the weak cold front slowly moves through our
region. A downward trend in rain potential and increasing confidence
in prevailing VFR is favored to end the week as high pressure
develops near New England.

&&

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

&&

$$

SYNOPSIS...Kramar/WM
NEAR TERM...Kramar
SHORT TERM...Kramar
LONG TERM...Kramar
AVIATION...AK