994
FXUS61 KPBZ 180752
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
352 AM EDT Mon Aug 18 2025

.SYNOPSIS...
High pressure will provide a couple of days of dry weather
before the next disturbance arrives on Wednesday. Temperatures
will be on the increase through the week. Another trough will
impact the region by the weekend.

&&

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

- "Coolest" day of the week is Monday.
---------------------------------------------------------------

High pressure will be the main weather feature for today and
into Tuesday for the most part. Expect some low stratus to
remain over the area through the morning hours. Some isolated
instances of fog is possible as well through dawn and this is
mainly over the higher terrain and northern WV counties as
these locations received decent rainfall.

Heading into the coming day, dry conditions will persist. The
cooler airmass that moved into the area will result in some
cooler temperatures today. In fact, highs today will be several
degrees below normal in most cases. With light winds and
clearing skies, a comfortable day is in store.

By tonight, daytime cumulus development will dissipate allowing
for clear skies. This will allow for fog development across the
area and mainly in the valleys. The probability for MVFR
visibility for tonight will be around 25% in most places but the
northern WV ridges are looking at near 50% to 60% for MVFR
visibility due to fog. This impact will lessen by 12Z Tuesday
morning.

&&

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

- A few showers possible on ridges for Tuesday
- Needed rainfall could occur Wednesday
----------------------------------------------------------------

By Tuesday, the high pressure centered just north of the Great
Lakes will finally slide east into the New England area. This
will still keep a ridge axis southwest over the Upper OH Valley
region. This will keep drier conditions in place for Tuesday.
However, temperatures will be on the increase with the southerly
flow and mainly sunny skies expected. In fact the probs for
90 degree temps across the area is around 50% to 60%. Tuesday
night will feature above normal low temps with some locations
low temps near 70 degrees.

By Wednesday, with the jet now across the northern CONUS, the
next shortwave will drop into the Upper OH Valley. The probs for
precip increase as thunderstorms are expected to develop by
Wednesday afternoon. However, confidence is low for any severe
threat. There also stands the chance for a downburst potential
as some dry air aloft will be present. As well, the southerly
flow will pump more moisture into the area and thus a Marginal
Excessive Rainfall forecast will be in place for SW PA and
northern WV. All precip will begin to dissipate shortly after
00Z unless and organized complex lingers into the overnight
hours.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
KEY MESSAGES:
- More dry days on tap
- Temperatures above average
-------------------------------------------------------------------

Overall the cluster analysis illustrates good agreement in the long
wave pattern dominated by a mid level anticyclone in the southwest
and a transitory trough moving across southern Canada into the
northern United States by next weekend. Where things become less
certain is with the amplification of the aforementioned mid
level trough when it reaches the Great Lakes by next weekend.
This doesn`t have an impact on us with respect to precipitation
chances until day 6 and 7 of the forecast.

Trends continue to be drier during the late week window as the
result of subsidence on the west side of Hurricane Erin and the
baroclinic zone being well to our south in the heart of Dixie.
Elevated heat source will be the primary trigger for showers and
storms during peak heating hours. NBM 25-50th percentile precip
numbers for Thursday and Friday are near 0 for probs, while the
mean remains at a few hundredths. Will continue to keep these
numbers on the downward trend with values equating to slight
chance to at most chance verbiage in text forecasts.

The good news is that it doesn`t appear we will be adding to our
tally of 90F days at any of our climate sites.  The probability of
exceeding 89F for the long term is 20% or less. Meanwhile, our
air conditioners will get a break at night as well given lower
to mid 60s will be common. We are in the single digit
percentages of seeing overnight lows stay warmer than 70F at any
of our six climate locations.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
MVFR ceilings are likely before around 12z within post-frontal
cool advection. Dry advection within the boundary layer may
cause fluctuations in cloud coverage between BKN and SCT that is
not captured within TAFs. Cloud cover should preclude more than
patchy river valley fog.

NE to SW erosion of the stratocu deck is likely between 08-14z
as subsidence and dry advection filters in. VFR with dry weather
is then expected for the remainder of the TAF period. Generally
light wind will veer ENE with occasional afternoon gusts to
15kt.

Outlook...
VFR weather likely through Tuesday before a likely weakening
upper trough approaches from the northwest to offer elevated
shower/thunderstorm chances midweek. Ensembles strongly favor
high pressure and dry weather to end the week.

&&

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

&&

$$

SYNOPSIS...Shallenberger
NEAR TERM...Shallenberger
SHORT TERM...Shallenberger
LONG TERM...McMullen/Shallenberger
AVIATION...Rackley/Frazier