516
FXUS61 KCTP 081123
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
723 AM EDT Wed Oct 8 2025

.SYNOPSIS...
* Cold front brings an end to the rain and ushers in a breezy
  and cool Wednesday across the Commonwealth.
* High pressure yields another prolonged stretch of dry weather
  along with nighttime frost/freeze potential Thursday & Friday
  morning.
* A coastal storm may deliver showers and breezy conditions in
  southeast PA Sunday into Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Rainfall winners overnight were in northwest PA and along the
I-81 corridor where rainfall amounts between 1.25 and 2 inches
were observed. Showers are weaker and more scattered early this
morning with a cold frontal rain band evident in northeast PA
moving rather quickly southeastward. Bradford is already down to
50F with a dewpoint in the upper 40s. Meanwhile, southeast PA
METAR stations all show temperatures and dewpoints in the upper
60s ahead of the front.

Much drier/increasing northerly flow behind the cold front will
end rainfall from NW to SE across most of the area by 12Z/8AM
Wed. It will turn breezy and noticeably cooler today with mix
of sun and clouds. A strong 1030+ mb high pressure center will
migrate southeastward over the Great Lakes and bring ample
subsidence through the weekend. The airmass associated with
this seasonably strong anticyclone will be the coldest so far
this season and bring (after many days of above normal daytime
warmth) the first prolonged stretch of seasonably cooler Fall
weather to Central PA. Highs today will generally be in the 60s,
which is about 10 degrees cooler than it was on Tuesday.
Dewpoints will continue to drop all day as dry air advection
persists.

Gusty winds will gradually taper off tonight as high pressure
moves in from the northwest. We have high confidence in subfreezing
temperatures in McKean County by Thursday morning, which
prompted issuance of a Freeze Warning there. Temperatures will
drop into the middle 30s west of I-99 and north of I-80 as well.
Patchy to widespread frost is most likely in the Laurels and
along the northern tier of PA where a Frost Advisory is in
effect. There could be patchy frost along and east of I-99 and
along I-80, but uncertainty in how much wind will still be
present tonight precluded Advisory issuance overnight.
Additional expansion may be needed later today if confidence
increases in a less windy solution. East of I-99 and south of
I-80, lows on Thursday morning, low temperatures will range
between the upper 30s and mid 40s.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
Abundant sunshine, lighter winds, and the first cooler-than-
average day in awhile will describe Thursday`s weather across
the Commonwealth as high pressure inches closer. Max temps will
be ~5 degrees below the historical average for early October and
refreshingly low humidity will finally feel like fall.

High pressure makes its closest approach to Pennsylvania
overnight Thursday into Friday morning, which will promote ideal
radiational cooling conditions. The coldest morning of the
season so far is on tap for Friday morning, prompting a Freeze
Watch for all but the Lower Susquehanna Valley. Widespread
freezing temperatures are expected north of I-80 and in the
Laurel Highlands. Valley locations east of I-99 and south of
I-80 could also drop below freezing. Even if temperatures don`t
fall below 32F, frost is very likely across the entire forecast
area.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Surface high pressure remains in control through the first half
of the weekend with return southerly flow helping gradually
increase temperatures Friday and Saturday. Rain-free conditions
continue thanks to prevailing upper ridging ensuring a great
Saturday for fall festivities.

By Sunday, Pennsylvania will be sandwiched between a closed
upper low over the Great Lakes and developing surface low off
the Atlantic Coast. How these two systems interact will have
significant implications for our weather. If the two systems
stay separated, some light rain could affect far northwest PA
with dry conditions in the center of the Commonwealth and
rainy/windy weather farther east. Should the two systems
interact, a windier/rainier pattern comes into play, perhaps
extending all the way to I-99. Considerable uncertainty remains,
but the highest confidence forecast is that a wet/windy/cool
stretch is likely for southeast PA Sunday and Monday. With
Pennsylvania on the northwest side of the low, cloudy and cool
conditions would be favored for most if not all of the area into
early next week.

Longer-range guidance depicts that coast low eventually getting
shoved out to sea by approach high pressure, but ensemble
guidance varies widely with how quickly the unsettled pattern
will give way to improving conditions.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
Shower coverage has mostly cleared the area with returns mainly
east of KAOO/KUNV. Coverage of showers has trended towards
being more scattered in nature with MDT having the best chance
of receiving rainfall over the next two hours. There remains a
non-zero (< 30%) chance at IPT/LNS through 14-15Z; however,
confidence remains much lower compared to previous TAF cycles,
thus have taken out mentions in the 12Z TAF package. Rapid
clearing is being observed on recent ECONUS satellite with low-
clouds already scattering out low-level clouds and observations
already outlining clear conditions across portions of western PA
and eastern OH. These trends will continue further east based
on a combination of 00Z HREF and recent GLAMP guidance, thus
have taken a more aggressive route with clearing this forecast
cycle.

Scattered low-level clouds cannot be ruled out across the
northern half (BFD/UNV/IPT) of the area this afternoon with
otherwise clear conditions. Breezy winds will be the main
aviation challenge after 14-15Z, with northerly/northwesterly
winds topping out between 10-15 knots sustained and 20-25 knots
gusts based on a consensus of GLAMP/NBM guidance. Given the dry
air mass in the wake of the cold front, fog potential looks very
low Wednesday night into Thursday morning, thus no mentions in
the 12Z TAF package.

Outlook...

Thu...VFR.

Fri-Sun...Patchy AM fog, otherwise clear with VFR conditions.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM to 9 AM EDT Thursday for PAZ004-006-
010-011-017-024-033-037.
Freeze Watch from Thursday evening through Friday morning for
PAZ004>006-010>012-017>019-024>028-033>035-037-041-042-045-046-
049>053-058.
Freeze Warning from 1 AM to 9 AM EDT Thursday for PAZ005.

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Banghoff
SHORT TERM...Banghoff
LONG TERM...Banghoff
AVIATION...NPB