147
FXUS61 KPBZ 042249
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
649 PM EDT Fri Jul 4 2025

.SYNOPSIS...
High pressure will provide dry weather through the weekend with
temperatures rising to above normal through Sunday. An unsettled
pattern takes hold next week with daily rain chances and near
normal temperatures.

&&

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

- Mostly clear tonight, with warmer overnight lows as compared
  to this morning.
---------------------------------------------------------------

The Upper Ohio Valley sits on the eastern side of an amplifying
Midwest ridge this evening. Earlier ACARS soundings showed
sufficient moisture for scattered cumulus below mid-level
capping, and much of those clouds have mixed out during the
afternoon, and these will disappear by this evening, leading to
mostly clear skies. Also, can still see a thin band of Canadian
wildfire smoke settling south of the Mason-Dixon Line.

Still expect upstream cirrus to float into our region tonight,
some of it from convection over southern Lower Michigan. Some
modest warm advection will help bump low temperatures up a few
degrees as compared to this morning. Any patchy valley fog is
likely to remain east of Pittsburgh, where cooler temperatures
(upper 50s/lower 60s) occur over the warm rivers.

&&

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

- Mostly dry weekend save a rogue shower north of I-80 Saturday
- Increasing temperatures through Sunday
----------------------------------------------------------------

The ridge continues to build into the weekend as surface high
pressure meanders off the East Coast. This will allow for some
southerly return flow to ensue with warm advection underneath the
building ridge. 850 mb temps sneak up to 18-20C on Saturday
allowing for a 70-80%+ probability of MaxTs reaching 90F from
roughly US-422 and south. A bit more of the southerly flow will
push dew points up to the mid to upper 60s, so it will be a bit
more humid with heat indices in the low to mid 90s. Also can`t
rule out a shower or storm scraping the northern part of our CWA
aided by the lake breeze, but it may be tough for any updrafts
to punch through the layer of subsidence around 700 mb depicted
in HREF soundings.

Further warming ensues on Sunday as the flow picks up a bit more out
of the south and allows for stronger warm, moist advection. The
ridge will start to break down in response to an approaching trough
from the Great Lakes. The stronger flow should mitigate a lake
breeze and keep the day dry across the board but it will be hot with
heat indices up to the mid to upper 90s. Heat Advisory criteria
appears less likely to be reach at this point especially with
generally good confidence in the pattern and cloud coverage.

&&

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

- Showers and storms return Monday
- Unsettled pattern with daily rain chances for most of the week
- Temperatures dip back to right around normal
-------------------------------------------------------------------

Along with the aforementioned trough will be a weak cold front
diving out of the Great Lakes on Monday as low pressure tracks
well to our north. The continued deep layer southerly flow ahead
of the boundary will increase moisture with PWAT values
increasing near 1.5" locally as the higher values remain off to
our east coincident with the strongest flow. Some showers may be
ongoing in the morning with weak convergence, but expect that
reinvigoration would occur along the boundary with daytime
heating. Weak support and flow aloft may be a hindering factor
in deep convective development with very weak deep layer shear
in place (<20% for >20 knots) but probability for >1000 J/kg
SBCAPE is up to 70-80%. The boundary is likely to be slow moving
with the deep layer flow oriented parallel, so upscale growth
and training of heavy rain could be a concern given the PWAT
values and slow movement of the forcing. Probability for >1" of
rain is very low in the ensembles currently, but wouldn`t be
surprised to see a bit of an uptick when the CAMs become
available.

Rain chances will continue into the middle part of next week as the
aforementioned boundary stalls just off to our south. How far south
is a bit uncertain with some ensembles suggesting deeper upper
troughing and pushing it farther south, but either way should see
rain chances diminish late Monday before picking back up both
Tuesday and Wednesday afternoon and evening with diurnal trends.
Another developing low toward the latter half of the week looks to
bring the boundary back up north and continue the unsettled pattern
into next weekend.

Temperatures are favored to be right around normal with the cloud
coverage and rain around the area.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
High confidence in VFR for most ports through the period with
medium confidence in VFR for DUJ/FKL. The period will mostly be
defined by high cirrus overnight and calm to light southeast
winds, replaced by light southwest winds for the daytime hours
Saturday with mixing generating a few fair weather cu. There is
a chance of patchy valley fog overnight, though this remains low
probability to impact any given port.

There is a 10% to 20% chance of showers with perhaps a rumble of
thunder for DUJ/FKL in the afternoon/evening hours Saturday as
a weak wave moves in from the north, with some initiation
possible off of the lake-shore, but this remains low
confidence. If coverage does materialize, it is expected to be
isolated at best with dry air aloft.

Outlook...
General VFR is forecast through Sunday with the next chance of
any restrictions or thunder mentions on Monday afternoon/evening
with the next disturbance.

&&

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

&&

$$

SYNOPSIS...MLB
NEAR TERM...MLB/CL
SHORT TERM...MLB
LONG TERM...MLB
AVIATION...Milcarek