017
FXUS61 KPBZ 102317
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
717 PM EDT Sun Aug 10 2025

.SYNOPSIS...
Dry weather continues through Monday under high pressure. Shower
and thunderstorm chances return Tuesday and Wednesday with a
passing cold front. Temperatures will climb through Tuesday but
heat indices remain below advisory criteria.

&&

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

- Warm and dry with some afternoon cumulus
- Overnight lows a few degrees above normal
---------------------------------------------------------------

Surface high pressure across the Mid-Atlantic maintains strong
influence on the area to close out the weekend as mid-level ridging
strengthens just a bit and keeps high confidence dry weather in the
forecast. Modest southerly induced gradient flow will increase
temperatures a hair compared to Saturday as most reach into the
upper 80s with a few 90 degree readings plausible in the urban
areas. Dew points remain in check in the low to mid 60s, so it`ll be
warm, but heat indices remain close to air temperatures.

Afternoon diurnally driven cumulus will dissipate after sunset and
give way to a mostly clear but warm night. Lows will hold generally
5-8 degrees above normal with a light southerly flow the only thing
in the way of an otherwise very efficient radiational cooling setup.

&&

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

- Continued dry and warm on Monday
- Warmer Tuesday with some isolated showers/storms
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Dry weather continues Monday with a similar persistence forecast to
Sunday. Modest warm advection with southerly flow in the low levels
will bump 850 mb temperatures to the 18-19C range. With the
afternoon sky only dotted by some diurnal cu, highs a touch warmer
than Sunday are reasonable in the upper 80s with low 90s in the
urban areas and valleys.

Tuesday is looking to be mostly dry across the area with some flat
ridging and modest warming in the mid-levels overhead which should
suppress widespread convective initiation. Can`t entirely rule out
some showers/storms breaking through the cap and taking advantage of
an environment with a 40-70% probability of >1000 J/kg SBCAPE, but
lack of forcing will be the key issue and more likely keep
development isolated and tied to mesoscale features. Global models
are a bit stronger with the warm layer and less bullish on
instability while available CAMs suggest a bit of a deeper CAPE
profile, so will have to see how the finer details iron out.
Advertised PoPs from the NBM around 20-30% appear reasonable at this
point with orographic ascent and a lake breeze aiding in the better
chance, though the latter may be deflected too far north with
ambient southerly flow to bring much into our northern
counties.

The surface pressure gradient ahead of the approaching boundary
doesn`t get all that tightly packed, so not expecting notably strong
deep warm, moist advection in the south to southwest flow out ahead
of it. Still, dew points will climb back up into the mid to upper
60s with highs favored to reach 90 for a good portion of the area,
especially south of I-80. The resultant combination of heat and
humidity will be AppTs in the mid to upper 90s. A few locales in
urban areas and valleys could nose their way to near 100F heat
indices, but don`t see it being widespread and any showers/storms
would suppress that threat. Lows only dipping into the upper 60s/low
70s Monday and Tuesday nights with the warm daytime will bump the
heat risk up to moderate to locally major by Tuesday, so those who
are sensitive to heat should consider reducing their time outdoors.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
KEY MESSAGES:

- Shift in synoptic pattern increases chances of showers and
  storms Wednesday/Thursday
- Above-average temperatures noted late week

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Long-range ensemble guidance indicates a pattern shift Wednesday
into Thursday as a trough moves across the Great Lakes into New
England. This large-scale mechanism coincides with increasing
probabilities of showers and storms. Machine learning signals a
potential in isolated downbursts (straight-line winds) during
this period, through the timing of storms and any upstream
outflow from earlier convection may affect the overall severe
weather threat. A surge of low-level moisture from the Midwest
could support heavy rainfall in isolated storms, with narrow
swaths of 1 inch possible in any training cells. Despite this,
the overall threat risk remains low with our long stretch of dry
weather this month.

Cluster analysis indicates an increase in tropical activity west
of the Caribbean Friday into Saturday, which will need to be
monitored into the following week. At the moment, a broad trough
over the Ohio River Valley may keep tropical concerns out to
sea, lower the potential for East Coast impacts. Late in the
week, above-average temperatures are possible as a reinforcing
ridge builds over the central CONUS. The NWS HeatRisk map
highlights moderate to major impacts for our area Friday into
Saturday, with a 30-40% probability of reaching 90 degrees or
higher. However, the probability of reaching Heat Advisory
criteria are very low (less than 10%).

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
High probability VFR conditions continue through the TAF period
with high pressure. Light and variable wind is expected
overnight as the boundary layer decouples. 4-6 kft Cu
development is expected again Monday afternoon with light
southerly flow.

Outlook...
Approach/passage of an upper level trough and surface cold
front mid-week will increase precipitation chances and introduce
periodic restrictions Tuesday and Wednesday with probabilities
peaking on Wednesday (favoring the afternoon periods).

&&

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

&&

$$

SYNOPSIS...MLB
NEAR TERM...MLB
SHORT TERM...MLB
LONG TERM...Hefferan
AVIATION...Rackley/MLB