Mc Kees Rocks, Pennsylvania Weather Forecast Discussion

193
FXUS61 KPBZ 211034
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
634 AM EDT Sun Sep 21 2025
.SYNOPSIS...
Above normal temperatures will continue while shower and storm
chances increase later today and into next week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:
- Largely dry conditions today
- Continued above normal temperatures
---------------------------------------------------------------
Patchy fog is possible where rain occurred yesterday and sees
partial clearing, but otherwise, most spots will see at least
scattered cloud coverage. Low temperatures will bottom out 5 to
10 degrees above average with the increased cloud coverage due
to a crossing shortwave. Latest CAMs show very limited
convective activity through the afternoon, and model soundings
show warmer air in the lower levels keeping a lid on things.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
KEY MESSAGES:
- Rain chances increase tonight with a warm front
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Tonight the area will see increasing rain chances as a warm
front crosses the region, particularly over eastern Ohio
counties where latest ensemble guidance shows up to 50% PoPs.
Coverage and organization this evening with better deep layer
shear as a broad south/southwest 20-25 knot low level jet
develops beneath increasing veering flow up to 700 mb. HREF
joint probabilities for >1000 J/kg SBCAPE and 25 knots of 0-6km
bulk shear reaches around 25-30% which could point toward a low
end wind threat, though latest CAMs suggest arrival time around
sunset in our eastern Ohio counties which would not necessarily
be the most ideal time, and latest CSU-MLP guidance and CIPS
analog guidance do not show a wind threat for today.
SPC has maintained a Marginal Risk (1/5) for damaging wind for
eastern Ohio, but a lower severe threat is a plausible solution
in our area if arrival time does prove to be after sunset.
Additional shortwaves will support a continued chance of
showers overnight. Warm advection with elevated southerly flow
likely means lows won`t dip out out of the 60s across the area
save north of I-80. On Monday, the Day 2 Marginal was expanded
east almost to the ridges as there should be better shear to
organize convection. Still, the threat will primarily be
damaging winds. This is supported by latest machine learning
guidance.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
KEY MESSAGES:
- Measurable rain expected in the period
- Near average temperatures expected late week
------------------------------------------------------------------
Ridging over the northeast CONUS will weaken as an upper trough
drops in out of the north. This will result in increased west
southwesterly flow, elevated dew points, and enhanced vertical
wind shear that will increase chances for showers and
thunderstorms that will persist through midweek.
Through early Tuesday morning, ensemble guidance indicates a
probability exceeding 60% for at least a quarter inch of
precipitation for areas north of Pittsburgh and into eastern
Ohio. The probability of one inch of rain is considered low over
the 24 hour time period (less than 15%). As we progress into
the mid to late week time period, the potential for additional
rainfall and near- normal temperatures is noted due to an upper-
level low over the southeast CONUS. Overnight low temperatures
may remain 5 degrees above average with lingering low-level
moisture and increased cloud coverage.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Surface high pressure centered over New England will promote
generally dry weather for western PA/northern WV today while
sneaking a brief morning period of MVFR cigs to DUJ that
dissipate with a veering wind.
Daytime hours today are expected to feature scattered to broken
cu and wind veering to a more southerly direction that
occasionally gusts to 15-20kts (near 100% likelihood). There
remains a low probability for a very isolated shower between
KMGW and KPIT from 19z-23z, but probability of terminal impact
is too low for TAF mention. Of higher confidence is weak upper
shortwave movement to the west that likely will spawn a broken
line of convection (30-40% probability for lightning) through
the far eastern OH zones between 22z-04z.
Hi-res modeling suggests any convection generally dissipates
after sunset; however, due to lift with that shortwave, it is
possible an area of showers continues to advance ENE overnight
to produce at least some light rain at area terminals. Even in
this wetter scenario, probability remains low (less than 30%)
for MVFR cigs to develop Monday morning.
.OUTLOOK....
A series of shortwaves will provide varying rain chances
through the middle of the week. While VFR is likely to be the
predominant flight category through this timeframe, periods of
heavier rain and/or patchy morning stratocu may result in MVFR
restrictions.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...88
NEAR TERM...88
SHORT TERM...88
LONG TERM...88
AVIATION...Frazier

NWS PBZ Office Area Forecast Discussion