710
FXUS61 KPBZ 041714
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
114 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 TONIGHT/...
KEY MESSAGES:

- Dry and sunny with a touch of elevated wildfire smoke
---------------------------------------------------------------

Surface high pressure centered over the Mid-Atlantic and mid-level
height rises in response to an amplifying Midwest ridge will provide
a dry holiday with plenty of sunshine. Dry northwesterly mid-level
flow and weak surface wind will keep dew points down with further
diurnal mixing expected this afternoon dropping values into the
upper 50s/low 60s. Afternoon highs will reach a touch above
climatological norms, but with the low dew points, it won`t feel too
sticky out there. The one fly in the ointment is a narrow strip of
wildfire smoke conveniently located atop our CWA, but this will
remain aloft with little impacts to air quality expected.

Some cirrus likely filters in overnight from remnant convection to
our north, and this could limit otherwise ideal radiational cooling
conditions under high pressure with light to calm wind and similar
conditions to Thursday night. Still, expect that some river valley
fog is possible, especially if the cirrus coverage comes in on the
thinner side. Otherwise, a beautiful day and evening to enjoy
festivities.

&&

.SHORT TERM /SATURDAY 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 /17Z FRIDAY THROUGH TUESDAY/...
High confidence in VFR through the TAF period under the
influence of high pressure with a generally light afternoon
northwest wind and a few diurnal cu.

A slight influx in high level clouds overnight from convection
north of the region should limit pre-dawn valley fog.

Outlook...
VFR under the influence of high pressure is favored through
Sunday afternoon.

Hi-res modeling suggests a low end (20-30
percent) potential for convection to trickle towards FKL/DUJ
Saturday afternoon in association with a shortwave rounding the
upper level ridge. Otherwise, late Sunday into Monday will be
the period where shower and thunderstorm chances increase with
the approach of an upper shortwave and surface frontal boundary.
Ensemble models favor an active weather week with restrictions
mainly tied to convective activity.

&&

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

&&

$$

SYNOPSIS...MLB
NEAR TERM...MLB
SHORT TERM...MLB
LONG TERM...MLB
AVIATION...Frazier