606
FXUS61 KCTP 101257
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
857 AM EDT Fri Oct 10 2025

.SYNOPSIS...
* Frost/freeze conditions will end the growing season across at
  least the northwestern half, if not more, of central PA this
  morning (pretty much right on schedule).
* Columbus Day weekend becomes wet with heavy rain and gusty
  winds possible over eastern Pennsylvania Saturday night into
  early Monday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Frost/freeze headlines will expire at 9AM. The coldest minimum
observed temperature this morning was 23 degrees at a CWOP site
in Smethport, PA (McKean County) and also from a spotter in
Potter County.

Previous Discussion:

Big sfc high slides eastward and out to sea today. A few clouds
are threatening to move up from the south today. But, dry air
and subsidence will keep the forecast sunny/mostly sunny. Temps
get closer to normal than yesterday despite the chilly/frozen
start to the day.

We`ll be able to cross of many of the zones in our CWA from the
growing season. The climatologically mean date of the first
freeze of the season is Oct 1st over the far N and Oct 11th N
and W of I-99. Many locations are already below freezing,
including much of Centre County, and the rest are within 2
degrees of freezing. Look for Public Info Statement later today
on which zones/counties have been crossed off and will not
receive any further freeze/frost products until the spring warm
up occurs.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
With the weakening high well off the coast, the upper low/trough
advancing from the northwest will align with the one over the
Deep South. The developing storm along the FL Atlantic coast will
start to inch northward on Sat. On-shore flow and the moisture
drawn poleward by the SErn upper trough will produce rain well
north of the deepening sfc low. Some rain (drizzle?) looks to
get into SErn PA Sat aftn while the instability over NWrn PA
(due to the upper trough and above normal temps) leads to SHRA
and perhaps a TSRA or two. The rain and showers collide over
Central PA Sat night when the deeper trough hits the big
moisture. The heaviest rainfall won`t occur until the long range
period, but some places in the Central mtns may pick up 0.5"
Sat night alone. Temps will be 0-5F above normal for Sat despite
the thickening clouds, and a very mild night follows with all
the clouds. The wind will pick up out of the ENE in the SE third
of the CWA, but gusts shouldn`t get near 25KTs at that point.
GFS has the sfc low a little farther north than NAM does late
Sat night. But, the result is the same: rain. However, the
SHRA/TSRA over the NW get quashed (and even nudged back to the
west at first) by the subsidence around the Nor`easter much the
same a there is usually fair weather surrounding a tropical
cyclone.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
A strengthening coastal low pressure system will move slowly
north along the Mid Atlantic (Delmarva/NJ) coast Sunday into
Monday. Very strong easterly/onshore flow (up to -4SD@850mb)
could bring heavy/soaking rain bands to parts of eastern PA.
Primary impacts at this juncture would be a somewhat limited
risk of flooding along with potential for wind gusts >35 mph. We
continue to highlight the heavy rain/wind risk in the HWO
particularly over the Lower Susquehanna Valley.

The phased upper level system and coastal low are projected to
track eastward Tuesday, bringing and end to the rain. Breezy
conditions may persist into midweek as p-gradient remains
fairly tight with high pressure drifting southeast from the
Great Lakes. Expect an improving/drying trend on balance with
seasonal cooling trend Tue-Thu.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Widespread VFR conditions prevail through Friday evening under
mainly clear skies. The chance for MVFR ceilings will increase
at most central PA airfields late Fri night into early Sat
morning as low level easterly flow lifts air with Atlantic
origin up and over the terrain of Pennsylvania. MVFR cigs are
expected to expand in coverage through the day Saturday, with
clouds converging from the northwest (upper shortwave trough)
and southeast (coastal low). Rain chances increase late Sat into
Sat night.

Outlook...

Sat Night-Mon...Low clouds and rain/wind potential increasing
particularly over the southeast airfields.

Tue...Continued breezy with rain ending/clouds breaking with
gradual improvement.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Dangelo/Steinbugl
NEAR TERM...Dangelo/Steinbugl
SHORT TERM...Dangelo
LONG TERM...Steinbugl/Evanego
AVIATION...Colbert/Bauco