274
FXUS61 KPBZ 091802
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
202 PM EDT Thu Oct 9 2025

.SYNOPSIS...
High pressure provides dry and cool conditions into the upcoming
weekend. The next chance of rain arrives this weekend, as
weakening Great Lakes low pressure combines forces with a
developing coastal storm system.

&&

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

- Clear and quiet
- Temperatures around 5 degrees below normal, with frost/freeze
  conditions
---------------------------------------------------------------

High pressure tracks to our north tonight across New York State
and into western New England by morning. Diurnal cumulus have
been few and far between this afternoon, given the overall dry
column (0.25 precipitable water on the 12Z PBZ sounding).
Afternoon highs are still on track to reach the upper 50s to
lower 60s in the majority of cases.

This clear sky trend will continue tonight, although some
localized steam fog may be possible again over the larger
rivers. The main question centers around temperatures and the
frost/freeze potential. The surface high track keeps a very
modest surface pressure gradient over our region, with light
easterly low-level flow tonight. While radiational cooling will
not be ideal due to this, the dry air mass with dewpoints
dropping into the upper 20s to mid 30s will still support
conditions capable of producing frost/freeze conditions. Still,
the Laurel Ridges in particular are tricky - the ridges are a
bit more likely to hold on to wind overnight, and nearby valleys
may experience a bit of a downslope effect from the easterly
flow, if it remains strong enough.

Ended up going with a NBM mean/10th percentile temperature blend
with a few tweaks, similar to previous shifts. This supports
freezing or just below temperatures mainly to the north of
Pittsburgh and in eastern Tucker County, and this is where the
Freeze Warning has been placed. Frost Advisories were hoisted
for other counties, save for portions of northern West Virginia
and eastern Ohio. The aforementioned Laurels have a Frost
Advisory for now, and cannot rule out the need for an upgrade
here. The easterly flow/non-ideal radiational cooling does
provide a hit to confidence.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
KEY MESSAGES:

- Slight warming trend and dry conditions through Saturday.
- Increasing clouds Saturday afternoon.
----------------------------------------------------------------

The high will weaken as it moves eastward off the New England coast
by Friday night with a ridge extending southwestward to eastern
Kentucky. This will help to maintain mostly clear skies tomorrow.
Wind is forecast to shift out of the southeast allowing for air to
warm as result of downsloping along the ridges. Highs are forecast
to reach into the mid to upper 60s, around average temperatures for
this part of autumn. Light southeasterly wind will persist overnight
inhibiting efficient radiative cooling, resulting in warmer
overnight lows into the 40s.

The ridge will weaken as it moves eastward on Saturday. Most of the
region expected to remain dry with highs in the upper 60s/lower 70s.
Increasing clouds expected to the northwest moving into Saturday
afternoon with an upper level trough approaching from the
northwestern Great Lakes region.

&&

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

- Chance for measurable precipitation Saturday night into Sunday
- Temperatures in the upper 60s and lower 70s
- Drier pattern returns next week.
-------------------------------------------------------------------

By Saturday night, an upper-level trough in the area will bring
a chance for measurable precipitation Saturday night through
Sunday night. There is a higher probability (>75%) for
measurable precipitation for western Pennsylvania and northern
West Virginia while a 55%-75% probability in eastern
Ohio/northern West Virginia panhandle. High temperatures will
slightly cool into the low to mid 60s on Sunday.

Models have been showing good continuity with this trough
phasing with a coastal low off the Carolina coast on Sunday.
There is a higher relative level of uncertainty in these
scenarios mainly with the strength of the low/trough. Guidance
shows relatively good agreement in ridging building back in over
the eastern CONUS, however, there is uncertainty with the
strength of the ridge as the trough moves offshore.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VFR conditions are forecast for the next 24 hours with high
pressure tracking north of the region. Isolated diurnal cumulus
will collapse with sunset, with a clear overnight and perhaps a
few high clouds by midday Friday. Steam fog may occur once again
on the larger rivers given expected cool air temperatures, but
any terminal impact should be brief at best. Light east wind
through tonight will veer towards the southeast Friday morning.

.OUTLOOK...
VFR is expected through Saturday under high pressure.
Restriction and shower potential returns Saturday night through
early Monday as an upper level low tracks southeast across the
region.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Frost Advisory from midnight tonight to 9 AM EDT Friday for
     PAZ020-021-029-031-073>076-078.
     Freeze Warning from midnight tonight to 9 AM EDT Friday for
     PAZ007>009-013>016-022-077.
OH...Frost Advisory from midnight tonight to 9 AM EDT Friday for
     OHZ039>041-048>050-057-058.
WV...Frost Advisory from midnight tonight to 9 AM EDT Friday for
     WVZ001-002-510>513.
     Freeze Warning from midnight tonight to 9 AM EDT Friday for
     WVZ514.

&&

$$

SYNOPSIS...CL
NEAR TERM...CL
SHORT TERM...Lupo
LONG TERM...Lupo
AVIATION...CL