598
FXUS61 KPBZ 212329
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
729 PM EDT Thu Aug 21 2025

.SYNOPSIS...
Daytime temperatures will be near normal today. The region will then
gradually warm into the upper 80s by Saturday. Sunday, an upper
level trough will bring a cold front through allowing temperatures
to drop below normal by Monday. Cool temperatures will last through
mid-week.

&&

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

- Evening showers in the ridges
- Lows in upper 50/lower 60s.
- Potential for river valley fog tomorrow morning.

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

Update...
Updated for a few showers that have developed across the ridges
along an inverted surface trough. These should gradually
diminish later this evening as temperatures fall below
convective thresholds.

Previous discussion...
Portions of eastern Ohio, northern West Virginia, and
southwestern Pennsylvania will see more clearing before
northwestern Pennsylvania by late evening. Overnight, sky
coverage will continue to decrease region-wide as northeasterly
wind becomes light.

Due to light wind and mostly clear skies, temperatures are expected
to drop into the lower 60s/upper 50s. There is also a chance for
river valley fog to develop with the calm/cool conditions.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
KEY MESSAGES:

- Dry weather and temperatures in the mid-80s on Friday.
- Precipitation chances return Saturday into Sunday with a passing
cold front.
----------------------------------------------------------------

A high over the Ohio River Valley will result in dry weather and
warmer temperatures through the start of the weekend. Temperatures
are forecast to warm into the mid to upper 80s by Saturday. During
this time, wind will shift from light out of the east-northeast on
Friday to 5-10 mph out of the southwest by Saturday afternoon.

By Saturday evening, an approaching cold front associated with an
upper-level trough will increase chances of precipitation overnight
into Sunday. Western Pennsylvania and northern West Virginia are
likely to receive measurable precipitation while there is about a
40% probability in eastern Ohio. Total rainfall accumulation will
remain relatively low with the chance for > 0.25" is 30%-40% for
areas east of Pittsburgh and less than 25% chance to the west.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
KEY MESSAGES:

- Cooler weather during first half of next week; highs in the
  70s and lows in the 50s.
- On Tuesday, rain showers possible with northwesterly flow off
  the Great Lakes.
-------------------------------------------------------------------

There is high confidence in a persistent troughing over the eastern
CONUS during the first half of next week. This should keep
temperatures below average through the first half of next week with
highs in the 70s and lows in the mid to high 50s.

On Tuesday, there is a forecast northwesterly flow. With the warm
lake waters (20C [68F] or warmer) and cooler 850mb temperatures (4-
7C [39-45F]), there is a chance that lake-effect rain showers could
pop-up Tuesday afternoon over northwestern Pennsylvania and along
the Appalachian ridge-line in PA.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR, with isolated MVFR, cloud cigs continue across much of the
area with low level moisture in place, and an inverted surface
trough across the region. These clouds are expected to gradually
decrease overnight, though some MVFR to IFR fog and stratus will
likely develop late with low level moisture in place.

The fog and stratus should mix out Friday morning, with model
soundings and the CU rule indicating a diurnal cumulus cloud
layer will remain through part of the day. This will likely
result in VFR cigs, until scattering out later in the day as
high pressure begins to build in from the west.

Outlook...
General VFR is expected Friday into Saturday as high pressure
moves east across the region. A prefrontal trough could result
in a few showers or thunderstorms on Saturday, before higher
chances of showers/storms arrive with a Sunday cold front.
Subsequent upper troughing and cool air aloft could result in
patchy cig restrictions north of PIT Monday and Tuesday, along
with a few scattered showers.

&&

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

&&

$$

SYNOPSIS...Lupo
NEAR TERM...WM/Lupo
SHORT TERM...Lupo
LONG TERM...Lupo
AVIATION...WM