557
FXUS61 KPBZ 170013
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
813 PM EDT Mon Jun 16 2025

.SYNOPSIS...
A few showers and thunderstorms are expected tonight. The
flooding threat continues through Tuesday but expands areawide
while Wednesday and Thursday may each have lower probabilities.
The active pattern should break this weekend, followed by area
temperatures climbing into the 90s.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
KEY MESSAGES:

- Rain chances continue overnight and may continue low-end
  flooding concerns primarily across eastern OH, the northern
  WV panhandle, and southwest PA.
- New flood headlines may be issued overnight

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

A quasi-stationary boundary remains situated south of I-70 this
evening. With low-level warm advection over the last 2-4 hours,
convection remains limited due to weak forcing. As an outflow
boundary approaches from the west and moves into eastern Ohio, a
few spotty showers and isolated storms may briefly develop.
However, more recent high-resolution model guidance has lowered
confidence in flooding issues through 10pm. As a result, the
Flood Watch was cancelled early.

Normally, the loss of diurnal heating and the environment being
worked over by outflow boundaries would result in decreased
shower coverage and low rainfall rates during overnight hours.
However, generally after 06z, a weak 700mb "jet" approaches the
area from the southwest with convection likely ongoing along
its leading edge. Hi-res model soundings suggest upwards of
500-750 J/kg elevated CAPE focused below -10C, which coupled
with PWATs increasing to near 1.8 inches, would continue
supporting efficient warm rain processes. As a result, there is
some concern that showers with moderate to heavy rain rates
could persist overnight, particularly along a swath from
Zanesville, OH to Pittsburgh or Butler in SW PA. We will closely
monitor upstream observations and hi-res model trends and may
need to issue a new flood headlines.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
KEY MESSAGES:

- Flash flood threat spreads areawide, with probabilities
  highest in locations previously impacted by flooding.
- Isolated instances of a damaging wind threat south of I-68.
----------------------------------------------------------------

A lower Ohio River Valley trough will start to slide east as
embedded 700mb shortwaves within increased southwesterly flow
are expected to promote more widespread shower and thunderstorm
coverage during the day Tuesday. The environment will remain
similar to the Sunday/Monday setups (near record high PWATs,
saturated grounds) save for two points which may counter each
other: stronger forcing will better aid storm development and
coverage (increasing flood threat) and storm motion will be
closer to 20kts (lowering the flood threat). Latest ensembles
suggest the focus for the heaviest rainfall could be across the
northeastern portion of the local forecast area, roughly between
Pittsburgh and Dubois, with more scattered or isolated instances
of heavy rainfall elsewhere across the area. However, given
that the region has be inundated with recent rain and many
counties have already seen impactful flooding, the messaging
remains the same areawide: Heavy rain showers and thunderstorms
pose a flash flood risk with potentially impactful flooding,
especially in locations that have previously seen flooding.

Unsettled southwest flow continues Tuesday night as additional
embedded shortwaves and jet induced ascent support rounds of
showers and isolated thunderstorms, though the focus for
greatest coverage shifts to areas generally south of
Pittsburgh. The flood risk could continue with these into early
Wednesday morning, especially if they impact any locations that
have already experienced flooding issues due to recent rain.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
KEY MESSAGES:

- Showers and thunderstorms continue Wednesday and Thursday,
  including increasing severe potential.
- Hot and dry weather returns this weekend into next week.
-------------------------------------------------------------------

Convection from Tuesday night departs the area to the east
Wednesday morning. Meanwhile, a more potent upper trough
advances eastward across the Great Plains and towards the Great
Lakes, resulting in strengthening deep- layer west-southwesterly
flow downstream over the Ohio Valley. Weak 500mb height rises
over the local area could provide enough subsidence aloft to
inhibit shower and thunderstorm activity Wednesday afternoon
and evening, with model soundings suggesting a rather stout
capping inversion forming near 700mb. This would be for the
best, as the same soundings also suggest that the strengthening
deep-layer flow, lingering low-level moisture, and dry air aloft
(due to the aforementioned subsidence) would otherwise support
damaging winds (1000+ J/kg DCAPE) and large hail (2500+ J/kg
SBCAPE) in storms.

The upper trough continues to advance eastward across the Great
Lakes Wednesday night into Thursday. As it approaches, height
falls and strengthening large-scale forcing overspread the
region, leading to showers and thunderstorms forming over Ohio
and moving east across the local area. These storms will still
carry a severe weather threat, primarily for damaging winds and
large hail. The Storm Prediction Center currently has much of
the local area in a Marginal Risk (Level 1 out of 5) during that
period. The heavy rain and flooding threat will likewise
continue with these storms, although faster motions will help
limit residence time in any one location and therefore the
threat will become more isolated to areas that already flooded
due to heavy rains in recent days.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
MVFR cigs continue generally along a line from BVI to LBE and
points north. These should continue for much of the night on the
northern side of a low level boundary across the area.
Thunderstorms are possible this evening at ZZV as convection has
fired to the south of this boundary, where clearing and diurnal
instability developed. Otherwise, expect additional showers and
embedded thunderstorms overnight as an upper level wave moves
along the boundary, under a mid level jet. Expect cigs to lower
to MVFR, and patchy IFR, by morning with low level moisture in
place.

The boundary will lift north Tuesday, as additional upper level
lift crosses the area. Expect numerous showers and thunderstorms
by afternoon, with associated vsby and cig restrictions.
Included a tempo mention for thunderstorms for the most likely
time of occurrence. The convection should gradually diminish
Tuesday evening with the loss of daytime heating and diurnal
instability.

Outlook...
Periodic restrictions are expected through Wednesday as another
upper level wave crosses the region. More widespread
showers/thunderstorms are expected late Wednesday into Thursday
with the approach and passage of a cold front. Late night/early
morning stratus and fog is also likely. General VFR is expected
to return Friday as ridging begins to build in.

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Cermak/Hefferan
SHORT TERM...Cermak/Frazier
LONG TERM...Cermak/Frazier
AVIATION...WM