934
FXUS61 KPBZ 152023
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
423 PM EDT Wed Oct 15 2025

.SYNOPSIS...
A Frost Advisory tonight and Freeze Watch for Thursday night
highlight the potential for frost and freeze conditions the next
two days that could impact outdoor vegetation. Dry conditions
and temperature moderation will occur into Saturday before
likely widespread rain ahead of a cold front arrives Sunday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
KEY MESSAGES:

- Dry conditions continue with near-normal temperatures
- Frost and isolated freeze is possible late tonight and early
  Thursday for much of the area
---------------------------------------------------------------

Surface high pressure centered over the Michigan Peninsula will
promote dry weather the rest of this afternoon and into the
overnight period. Mid to upper level clouds are expected to
thin/dissipate through tonight as warm/moist advection with
height rises aloft slow with weak shortwave movement through the
New England region.

Lower area dewpoint, light wind, and clear skies offers the
potential for strong radiational cooling overnight that poses a
risk for frost formation. A Frost Advisory remains in effect
between midnight and 9am Thursday for areas that show at least
50 (and closer to 80-90) percent probabilities for the ideal
frost combo of cold temperature, light wind, and high humidity.
Pockets of freezing/sub-freezing temperature can`t be ruled
out, especially within valley locations north/east of Pittsburgh
as well as Canaan Valley (WV), but are too localized or low
confidence for freeze highlights at this time.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
KEY MESSAGES:

- Frost conditions are likely areawide Thursday night/Friday
  morning, with Freeze Watch in effect for the eastern two
  thirds
- Precipitation free weather conditions with temperature
  moderation Friday
----------------------------------------------------------------

High pressure will continue to dominate the region Thursday into
Friday as the cooler air mass becomes fully in place Thursday
morning. Daytime highs will run a few degrees below the daily
average Thursday but are likely to feature plenty of sunshine.
Height rises and continued insolation Friday is expected to
moderate temperature near seasonal levels before high clouds
increase late in the day.

The most notable impact weather of the period will be frost and
freeze potential Thursday night into Friday morning. Ensemble
guidance is bullish (60-90% probability) on sub-freezing
temperature for locations north and east of Pittsburgh, which
lent to the issuance of a Freeze Watch. The Freeze Watch was
extended a county or two westward where guidance is a bit more
uncertain (30-60% probability for freezing temperature),
suggesting it may be more localized or just exclude urban areas.
Given there is still potential, the watch included these
counties for awareness but final Freeze Warning headlines may
end up trimming some of these areas out. Even if freeze isn`t
achieved, there is fairly high confidence (60-100%) for almost
the entire forecast area to see Frost conditions by Friday
morning. Frost headlines are likely, but will wait on issuance
to ensure easier public messaging tomorrow.

&&

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

- Above average temperatures return Friday into the weekend
- Breezy conditions and increasing rain chances along a cold front
on Sunday
- Cool and dry weather returns early next week

-------------------------------------------------------------------

The long term begins with a deepening trough over the central CONUS
and a narrow upper ridge over the eastern seaboard pushing eastward
over the Atlantic. A rather potent shortwave ejects eastward from
the central Rockies during the day Saturday, traversing the Plains
and reaching the Mississippi Valley overnight Saturday into early
Sunday morning. Meanwhile, a surface low develops in the IA/WI/IL
vicinity, which rapidly deepens and lifts northeast towards the
Great Lakes, eventually becoming vertically stacked beneath the
parent shortwave. As all of this occurs, it causes deep-layer
southwesterly flow to strengthen downstream over the Ohio Valley and
lower Great Lakes, which in turn brings moisture and unsettled
weather back to the local area Saturday night through Sunday night.
This will also result in a warming trend for temperatures Saturday
and Sunday, with highs climbing into the low 70s each day.

The hazards associated with Sunday`s forecast are two-fold. First,
the stacked low moves closer in proximity to the local area as it
crosses the Michigan lower peninsula and southern Ontario, which
will cause the pressure gradient between it and a broad surface high
centered off the southeastern U.S. coast to tighten. This will
result in an uptick in non-convective winds. Latest probabilities
for max wind gusts exceeding 30 mph on Sunday are 70-90% across the
entire area, while probabilities for max gusts exceeding 40 mph are
as high as 50% in the Pittsburgh-Wheeling corridor of southwest PA
and the northern WV panhandle. The second hazard will be showers and
thunderstorms associated with this system. Instability will be weak,
as highlighted by an NBM mean SBCAPE of only 100-200 J/kg and a 95th
percentile of 400-500 J/kg. However, wind shear will be strong (LREF
mean sfc-500mb shear ~50 kts), so if any deep updrafts are able to
form, they will be in an environment that supports at least a
limited damaging wind threat. Flooding is of lower concern at this
time given the preceding drought conditions and only around a 30%
probability of exceeding an inch of rainfall (mainly across eastern
Ohio) per the latest NBM.

Following the passage of the low, cooler and drier conditions set up
under northwest flow and building high pressure.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR is favored through the TAF period under the influence of
high pressure centered around northern Michigan. Northwest wind
gusts will intermittently hit 15-20kts the remainder of the
afternoon before surface winds decouple between 23Z and 00Z, and
become generally light into Friday.

There is potential for localized river valley steam fog early
Thursday morning given difference between air/water temperature
but only ZZV shows some probability (30-40%) for IFR/LIFR fog.
The likely more limited boundary layer moisture at other valley
terminals may prevent any fog layer to be deep enough to create
impacts (HLG/FKL/AGC/MGW).

.OUTLOOK...
Surface high pressure with height rises aloft favor VFR into
Saturday before a series of shortwaves ahead of the next cold
front bring increased rain and restriction chances.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory from midnight tonight to 9 AM EDT Thursday for
     PAZ007>009-013>016-020>022-029-031-073>078.
     Freeze Watch from late Thursday night through Friday morning
     for PAZ007>009-013>016-020>022-029-031-073>078.
OH...Frost Advisory from midnight tonight to 9 AM EDT Thursday for
     OHZ039>041-049-050.
     Freeze Watch from late Thursday night through Friday morning
     for OHZ041.
WV...Frost Advisory from midnight tonight to 9 AM EDT Thursday for
     WVZ001-002-509>514.
     Freeze Watch from late Thursday night through Friday morning
     for WVZ001-509>514.

&&

$$

SYNOPSIS...Frazier
NEAR TERM...Frazier
SHORT TERM...Frazier
LONG TERM...Cermak
AVIATION...Frazier/88