066
FXUS61 KPBZ 161115
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
715 AM EDT Sun Aug 16 2026

.WHAT HAS CHANGED...
12Z aviation discussion was updated.

&&

.KEY MESSAGES...
1) Overnight cluster of storms will bring heavy rainfall and
flood potential to eastern Ohio, northern West Virginia and
possibly southwestern Pennsylvania.

2) Sunday storm evolution is lower confidence as it depends on
the evolution of storms through dawn, but flash flood and
severe risks remain possible Sunday afternoon with potential
renewed storms.

3) After lingering showers dissipate Monday, there is fairly
high confidence in dry weather until Wednesday/Thursday, when
low pressure returns.

&&

.DISCUSSION...
KEY MESSAGE 1...
A weakening mesoscale convective complex driven by an apparent
MCV continues to track across the forecast area in Ohio. Here in
this region, the 2.0 to 2.2 PWATs have come to fruition and
rainfall rates out west show some 1.5 to 2.0 rainfall rates. The
short term hi res models show some uptick in rainfall rates as
it tracks east into the the WV panhandle and into Allegheny
County.

Here, the HREF hints at 1.00 to 1.70 rainfall amounts from
midnight through 10am moving east into the WV panhandle and the
PA border and eventually into Allegheny county. This is of
course only the mean values and higher values are certainly
possible and will thus keep the Flood Watch going.

KEY MESSAGE 2...
Confidence in what follows for Sun and Sun night drops off, as
atmospheric recovery/Sun-afternoon storm evolution will depend
on the mesoscale setup left behind by the overnight into Sunday
morning complex. While stable morning air should limit coverage
and intensity of convection at least into early afternoon,
redevelopment appears increasingly likely tied to a potential
mesoscale convective vortex developing from storms in the
Midwest/northern Plains. The ensemble models such as the LREF
suggest a second 500MB shortwave tracking across the IN and OH
region and into the forecast area. This may be the one needed
trigger to help the recovery form the morning convection.

Here, a pocket of 25-30 knots of 0-6km shear could provide
enough storm organization for a damaging wind potential, while
elongated/curved low-level hodographs (particularly enhanced by
a MCV if present) and sufficient 0-1km SRH suggest a lower-end
tornado threat for esewd-moving storms. Although the interesting
factor here is that the CAMs currently do not produce an
organized MCS and rather a cluster of storms developing.
Machine- learning guidance does support these assertions, likely
picking up on MCV- enhanced fields. Also, the same favorable
heavy- rainfall ingredients from the previous night will
continue, extending the flash flood threat into Sun night.
Another night of PWATs between 2.0 and 2.2 will keep a threat of
flooding across the area. Thus, the Flood Watch will continue.

KEY MESSAGE 3...
Diurnal stabilization should begin to limit convective coverage
and intensity late Sun evening, with a few showers lingering
into Mon with one last shortwave trough. By this point, PWAT
will be dropping off thanks to developing drier nwly flow,
which should help to taper the heavy-rainfall threat. High
pressure building in from the Great Lakes should end
precipitation by Mon evening. Dry weather is then favored until
Wed, when the next front could potentially arrive, although
this timing could change.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Showers and a few thunderstorms will continue across portions of
the area this morning as a warm front lifts across the region. A
period of MVFR to IFR cigs are also expected this morning with
low level moisture in place. Some improvement to MVFR is
expected through the afternoon with some surface heating and
mixing. Expect another round of thunderstorms to develop this
afternoon ahead of another approaching shortwave and prefrontal
trough. Some of these storms could be severe with damaging wind
and heavy rainfall. For now, indicated some wind potential in
the TAFs in the tempo mention for thunder.

Expect deterioration to MVFR, and eventually IFR, this evening
as the thunderstorms exit, and low level moisture lingers. IFR
stratus should then continue into early Monday morning.

Outlook...
Showers, restrictions, and possible thunderstorms are expected
for Monday as a cold front crosses the region. Other than early
morning fog, VFR is then expected through early Wednesday under
high pressure. Restriction and shower/thunderstorm chances
return Wednesday and Wednesday night with the approach and
passage of a cold front. VFR returns Thursday under high
pressure.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch through Monday morning for PAZ020-021-029-031-
     073>076.
OH...Flood Watch through Monday morning for OHZ039>041-048>050-
     057>059-068-069.
WV...Flood Watch through Monday morning for WVZ001>004-012-021-
     509>514.

&&

$$

DISCUSSION...Shallenberger
AVIATION...WM