667
FXUS61 KPBZ 161207
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
807 AM EDT Sat Aug 16 2025

.SYNOPSIS...
High pressure will keep hot and dry weather in the forecast
today. Widely scattered showers and thunderstorms will be
possible Sunday as a front crosses the area. The stalled front
will shift back north next week, bringing additional rain
chances Tuesday and Wednesday.

&&

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

- Quiet weather expected
---------------------------------------------------------------

Another quiet and clear night is in store, with very similar
conditions to Thursday night. Temperatures a few degrees warmer
and dew points a few degrees drier should keep coverage of river
valley fog spotty. Highest chances are south and east of
Pittsburgh.

High pressure across the Ohio Valley and into New England should
maintain dry conditions through the day. High temperatures will
push into the lower 90s across much of the region, save for the
I-80 corridor and higher terrain (80s). A stray shower or storm
may once again fire over the ridges with orographic lift, but
the probability for this is low.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
KEY MESSAGES:

- Increasing moisture and instability in WNW flow sets up chance
  for thunderstorms late Saturday night into Sunday
----------------------------------------------------------------

Upper Plains ridge will slowly shift east across the Great Lakes
by Sunday night as a cold front sags southwards across the area.
PWAT values across the Ohio Valley will begin to build into the
1.5-2.0" range by this afternoon. Latest radar imagery already
shows (poorly modeled) convection riding down the eastern side
of the ridge across WI and IL. Another round of convection is
likely to cross into the Ohio Valley by this afternoon and
evening, though staying west of our forecast area. Convection
moving our way overnight will head into a progressively more
stable environment across Ohio. Sunday morning showers chances
for us are unlikely, but non-zero. Given poor modeling of the
current upstream environment, will be monitoring for any
possible MCSs upstream that could possibly persist into the
area.

Spotty diurnal showers and storms may reform Sunday afternoon
ahead of the sagging cold front, but overall coverage continues
to look isolated to widely scattered. Some locations will remain
dry. Frontal passage is expected Sunday night, as the front
eventually stalls along the Mason-Dixon. Lingering evening
convection should diminish with frontal passage and loss of
daytime heating, leaving a mostly dry Sunday night.

Temperatures remain above average on Sunday, but will run a few
degrees cooler than Saturday.

&&

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

- Mainly dry on Monday as front stalls to the south
- Several rounds of showers/storms possible Tuesday and
  Wednesday.
- Low-probability rain chances Thursday and Friday
-------------------------------------------------------------------

Central CONUS ridging is likely to persist through mid-week,
keeping the area under northwest flow aloft. Dry weather is
expected Monday as the stalled front remains to our south, but
this is likely to lift northwards Tuesday and Wednesday as a
warm front, introducing several rounds of showers and
thunderstorms to the forecast those days with crossing
shortwaves.

As previously mentioned, troughs associated with recurving
tropical systems tend to overpreform. So would favor solutions
that have a stronger trough moving into Great Lakes and thus a
bit more vigorous rainfall event. This is is reflected by the WPC
Excessive Rainfall outlook for Tuesday. Will continue to monitor
guidance trends. NBM PQPF remains at 10-30% chance of 1"+ for
the period.

Guidance shows ridging extending from dominant and persistent
four corners upper high stretching across central Plains and
into Ohio Valley on Thursday so drier weather is expected.
However, diurnal isolated showers/storms are possible each
afternoon, especially across the higher terrain. Another
shortwave is expected Saturday into Sunday which may renew
precipitation chances. Typical timing errors and uncertainty
associated with Day 7 render this a relatively low confidence
precipitation forecast.

Monday and Tuesday are likely to be the warmest days of the week
(near 90 for some), with gradual cooling towards climo mid-week.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
High confidence /near 100%/ for VFR weather the duration of the
forecast.

High pressure will allow for another day of high based cu
between 5-6kft and passing cirrus clouds. Some of the more
recent HRRR runs have isolated showers developing in
southwestern PA around 23Z Saturday. Given this is a new
development in the predawn runs and amount of dry air and warm
temperatures above, do not think there is a need to include this
in any terminal forecast. We will be monitoring trends
throughout the day tho. Wind will be from the west less than 10
kts.

Outlook...
There is high confidence in VFR with dry weather through
Sunday morning with high pressure over eastern Canada. The approach
of a cold front within developing NW flow may increase convective
potential Sunday afternoon/evening, especially at the northern
sites, but confidence in coverage and timing is low. VFR
weather returns Monday and Tuesday. There could be patchy fog
Monday morning depending on where and if it rains Sunday.

&&

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

&&

$$

SYNOPSIS...Rackley
NEAR TERM...Rackley
SHORT TERM...Rackley
LONG TERM...Craven/Rackley
AVIATION...McMullen