681
FXUS61 KPBZ 060612
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
212 AM EDT Sun Jul 6 2025

.SYNOPSIS...
Hot and dry Sunday with a Major Heat Risk across the Pittsburgh heat
island. Rain returns on Monday with a boundary that stalls across
the region and brings daily rain chances throughout the week along
with near normal temperatures.

&&

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

- Heat continues to build today bringing a Major Heat Risk to the
Pittsburgh heat island
- Dry conditions expected
---------------------------------------------------------------

Our upper ridge is already beginning to flatten some in response to
a trough moving into the Great Lakes. Despite this, 500mb heights
are expected to remain north of 590dam across much of the region
Sunday. Stronger SFC and 850mb flow today strengthens warm and moist
advection pushing our high temperatures past where we stopped
yesterday. For much of the region (outside of the ridges) this
translates to and 80%+ chance to see high temperatures over 90
degrees and a nonzero chance to see the mercury strike 95 in
downtown Pittsburgh and some of our southern river valleys.
Increasing moisture should help pop a diurnal cu field across much
of the region but sunshine will be prevalent.

Heat advisory criterion are unlikely to be met but heat yesterday
combined with little overnight recovery and even hotter temperatures
expected Sunday push Heat Risk into the Major category across the
Pittsburgh heat island and portions of the Ohio River Valley. Those
without AC should take proper precautions and heat awareness is
recommended for all.

Diurnal cu winds down after sunset but skies can remain at least
partly cloudy overnight as moisture continues to rise. Overnight
lows rise once again and many areas can see upper 60s to low 70s.
Little overnight relief from the heat parlays the Major Heat Risk
into Monday.

&&

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

- Major Heat Risk remains across portions of the region
- Showers and storms return Monday with the chance for heavy rain
and isolated instances of flash flooding
----------------------------------------------------------------

The upper trough enters the region Monday and brings with it a weak
cold front draping southward from a low pressure system sweeping
through southern Ontario. Warm air and moisture advection continue
ahead of this front and give the region another chance to see high
temperatures north of 90 degrees (largely 60-80% south of I-80).
Continued moisture advection spurs our PWATs back up above 1.50
inches across much of the region and many locations see jumps of
0.50 inches in 24 hours. More moisture brings increasing clouds and
rising dew points which can return humid conditions by midday.

There remain low chances to see spotty shower coverage across the
region in the convergent air preceding the front but the main show
is expected to kick off with increasing heating and moisture later
in the afternoon. Showers and thunderstorms are expected along and
ahead of the front Monday afternoon and evening.

Overall shear available looks rather low with model soundings
indicating around 15-20 knots of deep-layer. This likely limits
deep, organized convection and tempers our severe threat. However
low shear, light cloud bearing layer-winds and slow downshear
vectors oriented along our boundary point towards a heavy rain
threat instead. Despite continued apathy from global ensembles the
HREF now pegs several areas across our I-80 counties as candidates
to see heavy rain with probabilities of greater than 1 inch of
rainfall between 40-60% in spots. There even is a small contour of
10-30% chance of greater than 2 inches of rain across northern
Venango and Forest Counties. Much of our region is currently in a
Marginal Risk (1/4) of excessive rainfall from WPC.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Unsettled pattern this week with daily rain chances along a
stalled boundary.
- Temperatures stay near normal.
-------------------------------------------------------------------

The boundary looks to slow and stall somewhere south of Pittsburgh
on Tuesday. This keeps rain chances near and along the boundary
elevated as we move later into the week. Heavy rain chances are also
remain elevated along the stalled boundary and southern and eastern
portions of the region have been included in a Tuesday Marginal Risk
(1/4) of excessive rainfall from WPC. Temperatures moderate some
behind this boundary, bringing highs back to near normal values for
this time of year.

Exactly where the front stalls remains dependent on how deep our
parent trough can become. Ensembles continue to prog the most likely
area as near the WV ridges. The highest coverage of rain and storms
through midweek is thus expected along these areas. Each day is
expected to feature a diurnal trend in storm coverage as daytime
heating fires storms along the boundary. PWATs near and along the
boundary remain elevated through the midweek and showers and storms
are expected to be efficient rainfall producers extending our flood
concerns.

Models continue to hint at a developing SFC low driving
northeastward through the Great Lakes late this week or into the
weekend. This will help to push our boundary back north late in the
week, moving rain chances with it.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
High confidence of prevailing VFR conditions at all terminals
through the TAF period. A few instances of fog are possible in
the river valleys but should stay away from the terminals.

Deep boundary- layer mixing is on tap to resume again heading
into the day on Sunday. Given weak deeper wind field, gusty
wind does not seem likely but ought to become prevailing light
out of the southwest. However, a modest afternoon cu field
6-7kft could result for a few hours starting around 17Z. Like
today, the afternoon cu would be expected to erode as heating
wanes.

Cloud cover will be on the increase for Sunday night as the next
cold front moves into the region. Some shower activity may be
possible towards the end of the TAF period.

Outlook...
Daily thunderstorm chances (and associated restrictions) return
Monday through the coming week, likely following a diurnal
pattern with peak probabilities occurring each afternoon and
evening.

&&

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

&&

$$

SYNOPSIS...AK
NEAR TERM...AK
SHORT TERM...AK
LONG TERM...AK
AVIATION...Shallenberger