288
FXUS61 KCTP 161913
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
313 PM EDT Thu Oct 16 2025

.SYNOPSIS...
* Seasonably cool days and crisp Autumn nights through Friday
* Modest warming trend/above average temperatures this weekend
* Weekend starts dry and ends wet: breezy/windy conditions and
  locally heavy rain showers probable Sunday into Sunday night

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Mostly sunny and seasonably cool/breezy today. Max temps in the
low 50s to low 60s are near to several degrees below mid
October climo. Daytime dryness will peak this afternoon with
minRH in the 25-35% range. P-gradient and strong northerly llvl
flow between exiting storm in the North Atlantic and high
pressure migrating to the southeast from the Upper Great Lakes
will result in 20-30 mph wind gusts focused over the eastern
portion of the forecast area. Despite some recent rainfall,
windy/dry conditions this time of year promote an elevated risk
of wildfire. Try to avoid burning if you can!

Minimum temperatures will reach a short term nadir overnight
with frost/freeze conditions probable across the majority of CPA
early Friday morning. Fcst low temps range from 25F in the
usually colder spots in the NW Alleghenies to around 40F in the
Harrisburg metro. Frost advy has been issued for the 7 zones in
the LSV where the growing season remains active. A persistent
light NNW breeze raises some concern for frost formation
especially in the eastern periphery of the CWA adjacent to PHI,
but overall risk/confidence is high enough to issue particularly
for the valley locations and sheltered rural/agricultural areas
(outside of the larger cities and towns) that should experience
the coldest temperatures.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Sfc ridge axis migrates slowly eastward Friday reaching eastern
PA by 12Z Saturday. This should allow for one more chilly night
particularly in the eastern/northeastern valleys. Max temps are
neutral to slightly warmer day/day with fcst highs 55-65F. High
to mid level clouds will steadily increase from west to east
Friday night into Saturday as WAA pattern ramps up heading into
the weekend.

500mb ridge axis shifts to the east on Saturday with milder air
surging into the area behind an increasingly strong SSW 850mb
LLJ. Lead perturbation in the Upper OH Valley could trigger some
showers across western/northwestern PA early on Saturday in the
vicinity of lifting warm front. Otherwise, it will be a dry
and milder start to the weekend with highs +5-10 degrees warmer
vs. Friday. With winds coming Sunday and Monday, it will be
advantageous to get any leaf peeping activities done on
Saturday before significant leaf off occurs.

Amplifying 500mb trough digging into the mid MS/lower OH valley
Saturday night will send a deepening/seasonably strong
sub-1000mb sfc low into lower MI by 12Z Sunday. Low level wind
fields strengthen in-kind and advect hi pw air >1" northeastward
from the Gulf. Blended model guidance favors increasing odds for
rain showers over the NW 1/2-1/3 of the forecast area overnight
Saturday through early Sunday morning. Noticeably milder readings
Saturday night with low temps trending +7-15 degrees warmer vs.
Friday night thanks to increasing clouds and southerly flow.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
16/12Z model guidance still not in full agreement concerning
the evolution of the sharpening/negative tilted upper trough
pushing east from the Great Lakes/Ohio Valley Sunday into
Monday. The EC remains the most amplified solution, showing a
deep 500mb cut- off low over PA by 12Z Monday. The GFS is much
flatter and more progressive with the CMC clustering closer to
the GFS albeit a tad stronger/farther south.

As the pattern details are ironed out with time, there are some
signals flashing for potential isolated svr storm/heavy rain
threat Sunday-Sunday night. There is no risk area highlighted by
SPC at this time, but some of the AI/machine learning guidance
does paint portions of south-central PA in a risk for severe
weather on Sunday afternoon thanks to ample shear, strong wind
fields, and marginally sufficient instability. Would expect a
MRGL or SLGT risk over some portion of south central PA with the
day 3 update issued first thing Friday morning. At the very
least, the tightening p-gradient and strong llvl wind fields
associated with this system will also bring breezy/windy
conditions which could easily blow around unsecured objects
including Halloween decorations.

As the system shifts east, rain showers should linger into
Monday followed by a drying trend Monday night into Tuesday.
Time of arrival of the next frontal system for Tue-Wed also in
question and is largely dependent on the speed/departure of the
Sun-Mon system. EC is again on the deep end of the guidance
envelope; max POPs into midweek are painted across the western &
northern mtns. Regardless, signal for a wet pattern over the
next week should continue to mitigate major concerns for fire
weather in the near term.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR conditions will continue through the rest of the day under
mainly clear skies. Wind gusts of 15 to 25 knots will continue
through the rest of the afternoon before dropping off after
sunset. Similar to last night, there is some potential for low-
level wind shear at our eastern TAF sites with winds at 2000
feet approaching 30 knots. The best chance will be at LNS, but
confidence is too low to include it in the TAF for now. Varying
amounts of high clouds will move through overnight, but all
sites are expected to remain VFR.

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...
Frost Advisory from 2 AM to 9 AM EDT Friday for PAZ036-057-059-
063>066.

&&

$$

SYNOPSIS...Steinbugl/Banghoff
NEAR TERM...Steinbugl/Banghoff
SHORT TERM...Steinbugl/Banghoff
LONG TERM...Steinbugl/Banghoff
AVIATION...Bauco