401
FXUS61 KCTP 171921
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
321 PM EDT Fri Oct 17 2025

.SYNOPSIS...
* Increasing clouds with light rain showers or sprinkles
  tonight into early Saturday morning over north central PA
* Clouds break for p.m. sun with noticeably milder temperatures
  to start the weekend
* The weekend ends wet/windy with gusty rain showers Sunday
  afternoon-Sunday night; trending breezy/cooler into Monday

&&

.NEAR TERM /THROUGH TONIGHT/...
Mid and high clouds continue spill south-southeastward this
evening into tonight around an upper level ridge migrating
eastward from the Great Lakes. A leading shot of low to mid
level warm advection/uvvel (ahead of the sfc warm front) will
trigger some light rain showers or sprinkles across north
central PA tonight into early Saturday morning. Low temps will
be +5 to +15 degrees higher than last night in the upper 30s to
lower 40s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Sfc ridge axis migrates slowly eastward and reaches eastern PA
by 12Z Saturday.

500mb ridge axis shifts to the east on Saturday with milder air
surging into the area behind an broad southwest flow aloft.
Early day clouds and leftover spotty light rain showers or
sprinkles will fade as they shift/exit to the east toward the
Poconos. Expect cloud breaks by the afternoon with increasing
southerly flow helping to boost max temps +7-15F higher vs.
Friday into the 60-70F range (+10-15F above climo along the
Allegheny Plateau and Laurel Highlands). On balance, a mainly
dry and milder start to the weekend.

Amplifying 500mb trough will take on a negative tilt as it
lifts through the Great Lakes/Ohio Valley into the Northeast on
Sunday. A deepening a surface low (sub-1000mb) associated with
the upper trough will track through Michigan into eastern Canada
toward James Bay. Strong southerly flow ahead of the low will
transport Gulf moisture northward and support a modestly moist
air mass into PA. A cold front trailing the seasonably strong
sfc low is expected to sweep eastward and serve as a focus for
one or more lines/bands of gusty rain showers (shallow
convective frontal rain bands) Sunday afternoon through the
first part of Sunday night. The setup is a common transition
season low CAPE/high shear environment with potential for
strong to locally damaging wind gusts along the convective
lines/frontal bands. Periods of heavy rain are also possible,
but given the progressive forward motion, we feel that that
flooding risk is pretty low or on the nuisance side (drought
conditions also a contributing factor). Primary risk would be
in urban or residential areas particularly where leaves clog
storm drains.

A tight pressure gradient and 3-6mb fall/rise couplet indicates
gusty winds will continue behind the cold front as the llvl
flow turns to the west. We adjusted NBM wind gusts higher to max
out in the 30-40 mph range or below wind advisory criteria for
now. This will be the first "windy" period this Fall with the
potential to blow leaves and unsecured objects (Halloween
decorations) around.

Max temps top-out in the 65-75F range in most areas on Sunday
with some locations possibly approaching 80F in the LSV. Expect
a steady drop in temps across the western Alleghenies Sunday
night with low temps -10F colder vs. Saturday night.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Breezy and cooler to start next week with rain showers exiting
the area Monday night. Wind gusts in the 25-35 mph range are
forecast during the day on Monday and will amplify the 24hr
cool down/maxT change of -10 to -20 degrees vs. Sunday.

After a brief dry period Monday night into Tuesday, the
remainder of next week looks unsettled and quite showery
(especially downwind of Lake Erie over NW PA and the western
Alleghenies) under the influence of large scale upper level
troughing and broad cyclonic flow. It`s conceivable that the
the first flakes of the season may be found over the higher
elevations along the Allegheny Front. I guess it`s that time of
year...

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A shield of high cirrus crossing the Great Lakes will continue
to move over the region through the rest of today and
overnight. Surface winds that have been gusty this afternoon
will diminish and become calm during the early evening hours
tonight, just after 00Z. The cloud deck will continue to build
in from west to east, and ultimately an overcast deck near
10,000ft AGL is anticipated over much of the region by sunrise
tomorrow. However, there is high confidence (>90%) in no
restrictions to flight categories due to the increasing clouds.
VFR conditions should prevail throughout this TAF package.

The only area that could see some concern would be over
northwestern PA near BFD. Scattered rain will likely develop off
the coast of Lake Erie late tonight, and a PROB30 group has been
included with BFD`s TAF to reflect the isolated chance of rain
over that airfield.

Outlook...

Sat...VFR. A few showers possible over northwest PA.

Sun-Mon...Restrictions possible in SHRA. Low probability of a
thunderstorm over northwest PA.

Tue...Lingering showers.

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...Bowen