Mount Lebanon, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

489
FXUS61 KPBZ 201751
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
151 PM EDT Sun Jul 20 2025

.SYNOPSIS...
Isolated showers/storms possible today with marginal severe
flood threats this evening/early overnight. Pleasant weather
early week with seasonable temperatures, no rain, and low
humidity. Heat, humidity, and storm chances return late week.

&&

.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:

- The marginal risk for severe weather has been reduced to just
  far southeast Ohio and a part or northern West Virginia, with
  a low probability of damaging winds from 6pm to midnight.
- A marginal risk of excessive rainfall overnight southwest of
  Pittsburgh.

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

Trends with the 12Z sounding indicate that severe weather
chances have reduced for most of the area today on a passing
cold front. There are a few reasons for this. First, a layer of
relatively moist air the the 0km to 3km layer will inhibit much
low-level instability generation even if profiles wet bulb.
Second, this aforementioned moisture has held a low stratus
deck through much of the morning, inhibiting efficient heating
near the surface needed for storm buoyancy. Third, a dry layer
between roughly 4km to 6km will be difficult to penetrate
without vigorous updrafts. This has prompted the SPC to "pull
back" their marginal risk for the majority of the area.

As the front moves farther south into southeast Ohio and
portions of northern West Virginia, there is some indication of
more mid-level moisture moving up from the west along the front
axis and a longer window to heat during the day, which might
suggest a higher chance of storms themselves, but lower modeled
DCAPE values between 300 to 400 J/kg would not be supportive of
damaging wind gusts. That would leave the only conditional
probability of severe weather dependent on storm motion alone,
mostly reliant on a cohesive shear-driven cold pool between
roughly 6pm and midnight. This low probability threat is
generally only possible for the southern fringes of the county
warning area.

Despite the lowered severe chances, a marginal risk for
excessive rain still persists, mostly overnight (10pm to 6am).
Though column moisture can be an inhibitor for severe, it is
more favorable for efficient rains. With PWATS pushing 2" with
warm rain processes in storms (HREF max suggestive of 1" to 2"
per hour rates), flooding is still possible, mostly southwest
of Pittsburgh, but would rely on shear parallel training with
storm motions of 20kts to 30kts. This would preclude widespread
flooding concerns, but the threat could not be ruled out with
HREF maxima suggesting localized 6hr totals of up to 2"
possible, bordering up against FFGs thresholds. Hence the
marginal risk for flash flooding persists.

Overnight lows south of and near the front in northern WV and
southeast Ohio will remain above average in low-moisture and
clouds, while areas north of Pittsburgh may see low below
average for the first time in a while with clearing, cold
advection, and dry advection. Patchy fog is possible in areas
that do see rain today.

&&


.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- High pressure will return dry conditions dry Mon through Wed
- Heat returns by mid week with heat indices approaching 100F
  by Thursday

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

High pressure will be the dominant feature through mid-week as
ridging builds over the eastern CONUS. This will result in the
return of dry conditions as subsidence and warm air aloft
suppresses any convection. Highest probabilities from any model
guidance for precipitation during any 12hr period through mid
week is less than 5%.  As heights continue to rise into mid-
week, temperatures and and heat indices will also increase.
&&

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

- Heat and humidity continue to increase
- Shower/thunderstorm chances increase Thursday and into
  weekend.
-------------------------------------------------------------------

Latest ensemble guidance shows the probability of max
temperatures 90F or greater near 100% by Thursday, and mean
apparent temperatures near 100F. By Friday, the ridge axis will
be east of the region and, as upper flow becomes more zonal, the
door for showers/storms will open again. Machine learning
guidance and analog guidance also suggest a return of severe
potential as well.
&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Tracking closer to current radar and satellite trends, a tempo
timing showers along a frontal passage has been included for all
ports. This will be earlier in the period for FKL/DUJ
(18Z-20Z), and track to the south as the front and shower
activity progresses down to MGW (04Z-08Z). Marginal MVFR/VFR
conditions are possible in showers with a temporary brief drop
in cigs/vis should one occur. Showers are fairly widely
scattered, so it is not a sure bet that any give port experiences
rain, through chances increase from north (30%) to south (50%).
Thunder could not be ruled out for any port today (chances in
any given shower are 10% to 30%), but most likely generally the
farther south you go. Because of this, some VCTS was denoted at
ZZV with the most likely arrival time of a potential storm.
Elsewhere, no mentions were included.

Behind the cold front, winds will veer more northerly and ceilings
are expected to fall again overnight with some cooling and
moisture along the cold front, which will be most likely south
of PIT. The farther north you go, the more likely chance of
clouds scattering to mostly clear skies with the arrival of
drier air behind the front. Because of this, the only port with
a >50% chance of MVFR is MGW for now near daybreak Monday.
Fog/haze is possible but generally less than 30% likely at any
given port; some haze is possible at ports that do see rain.
Mixing and scattering to widespread VFR is likely thereafter,
with perhaps a fair weather daytime cu deck Monday in light
northerly flow.

Outlook...
High confidence exists in high pressure promoting dry weather
and VFR conditions Monday through at least Thursday morning
before precipitation chances return late week into next weekend.

&&

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

&&

$$

SYNOPSIS...Milcarek
NEAR TERM...Milcarek
SHORT TERM...88
LONG TERM...88
AVIATION...Milcarek