827
FXUS61 KPBZ 131645
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
1245 PM EDT Mon Oct 13 2025

.SYNOPSIS...
Dry and warm conditions are expected Tuesday with a building
ridge. Frost and freeze potential builds Wednesday and Thursday
night. Above average temperatures expected over the weekend.

&&

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


- Warm and dry west of I-79 while cooling with a low
  probability afternoon sprinkle along the ridge line.
- Pockets of fog can`t be ruled out for Tuesday morning.
---------------------------------------------------------------

Lingering impacts from a surface low off the coast of NJ will
begin to fade later this afternoon and into the overnight period
as it weakens while high pressure gains better traction in the
Upper Ohio River valley. Until then, NE flow around the low will
provide an influx of low to mid-level moisture into western PA
that manifests as broken/overcast clouds and localized areas of
light sprinkles (mainly along the ridge line). This will limit
diurnal heating and keep most areas within a few degrees of the
average high temperature.  Farther west, a few diurnal cumulus
are possible but insolation will allow for better heating and
result in high temperature that is around 5 degrees above
average.

Subsidence is expected to erode area cloud cover overnight,
though ENE flow from the coastal low may still see lower stratus
spill into areas east of Pittsburgh along the ridge line. These
potentially clear conditions with some calming of surface wind
could create localized areas of fog. Hi-res modeling favors the
valleys where boundary layer moisture will be highest (20-60%
probabilities for half mile or less fog). There is also a weak
indication for advection fog across eastern OH but probabilities
(20-30%) are too low for grid mention at this time. Warm river
waters may also contribute to localized river valley fog
assuming calm winds.

&&

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

- Confidence high in dry conditions
- Frost/freeze possible Wednesday night and Thursday night
----------------------------------------------------------------

Confidence remains high that a ridge axis will continue to build
across the central CONUS today into tomorrow, gradually shifting
east into the Ohio River Valley as a cut-off low pivots over
California. This pattern will support above-average temperatures
and dry conditions through the period.

Overnight, clear skies will promote radiational cooling,
allowing temperatures to fall into the mid to low-30s. The NBM
probabilities of temperatures ranging between 32 to 35 degrees
is elevated (above 60%) for a large portion of the region. With
the growing season still ongoing, frost and freeze headlines
will likely be issued within the next 48 hours to cover
Wednesday night into Thursday morning.

How low temperatures dip Wednesday night into Thursday morning
will determine which areas may also require Frost/Freeze
headlines Thursday night into Friday. If a number of counties
experience a freeze, the growing season will end Thursday.

&&

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

- Above average temperatures return Friday into the weekend
- Rain chances return late this weekend

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

Long-range ensemble guidance remains consistent in showing the
aforementioned ridge axis pivoting over Pennsylvania by mid-day
Friday and lingering into early Sunday. This will maintain dry
and warmer-than-normal conditions through the weekend.


A passing trough and its associated cold front over the Great
Lakes will likely increase chance for rain late Sunday into
Monday. Current ensemble guidance indicates 24-hour totals
generally ranging from 0.25" to 0.50" across the region within
the 25th to 75th percentile range. However, a few ensemble
members indicate the potential for higher amounts, approaching
an inch in some location.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
MVFR to VFR stratocu will continue through this evening mainly
west of I-77 amid ENE moisture advection from a coastal low.
The loss of diurnal heating and increasing subsidence as the
coastal low weakens should help to either erode or lift cloud
decks to VFR for most terminals.

Uncertainty in conditions increases overnight in par due to
variances in the degree of moisture/convergence along the
ridge line east of Pittsburgh for bkn/ovc MVFR decks at DUJ/LBE
or if that mainly stays east of the Laurels. Additionally,
there is some hint for either low stratus/fog at these locations
IF wind calms enough to maximize radiational cooling. Greater
radiational cooling and some signs for potential advection fog
off Lake Erie may drive lower stratus/fog into eastern OH
(20-30% probability for IFR or lowering visibility at ZZV).

Even if that scenario plays out across eastern OH, diurnal
heating will aid stratus/fog erosion by 18z Tuesday.

.OUTLOOK...
High pressure will promote VFR conditions Tuesday before a dry
cold front crosses Wednesday that may create periods of MVFR
cigs shortly after its passage (30% probability of MVFR at
western PA and northern WV terminals).

High pressure is expected to dominate the region and maintain
VFR Thursday into the upcoming weekend.

&&

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

&&

$$

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