310
FXUS61 KCTP 041011
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
511 AM EST Wed Nov 4 2026

.WHAT HAS CHANGED...
* Lowered maxT on Saturday 11/7

&&

.KEY MESSAGES...
1) Unseasonably mild through Friday with 2.5 weeks-long dry
spell coming to an end overnight into Thursday

2) Trending cooler this weekend with light rain downwind of
Lake Erie

&&

.DISCUSSION...
KEY MESSAGE 1: Unseasonably mild through Friday with 2.5 weeks-
long dry spell coming to an end late tonight into Thursday

Anomalous upper level ridging and south-southwest flow aloft
will maintain unseasonably warm temperatures through late week.
Max/Min temps will be 10 to 20 degrees above the historical
average for the first week of November, but should fall short of
daily record highs (see climate section).

A leading frontal band of light rain should reach the western
Alleghenies around or shortly after midnight and continue
spreading eastward across central PA through Thursday morning.
Fcst rainfall amounts are 0.25" inch or less through 00Z Fri in
most areas and will end the 2.5 weeks-long dry spell.

The front slows/stalls near the I95 corridor Thursday night. A
shortwave trough/closed H5 low dropping southeast from the Great
Lakes is expected to reinvigorate precipitation along the
nearly stationary frontal zone on Friday which could clip the
far southeast zones/Lower Susquehanna Valley. Model trends have
been shifting this rain farther to the east/closer to the coast
over the past few cycles. A dry slot may keep most locations dry
Thursday afternoon into Friday following the initial period of
rain late tonight through Thursday morning.

KEY MESSAGE 2: Trending cooler this weekend with light rain
downwind of Lake Erie

Seasonably cooler/breezy pattern to start the first full
weekend of November. The passage of closed H5 low followed by
mean cyclonic flow favors persistent clouds and periods of lake
enhanced rain over the western and central Alleghenies on
Saturday. We were keen to manually adjust max temps a few
degrees lower on 11/7 to account for the cooler pattern shift
which looks to continue into early next week.

&&

.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
Current observations outline clear skies across the
Commonwealth which are likely to continue overnight through 12Z
Wednesday with high (~80-90%) confidence. These conditions will
promote valley fog potential, especially across eastern
Pennsylvania in the 06-12Z Wednesday timeframe. Recent REFS
guidance has continued to indicate that IPT will have the
highest probabilities (~70-80%) of fog formation, with MDT/LNS
also showing modest (~40-50%) probabilities of fog potential.
That being said, light winds continue at IPT and will need to
trend towards calm in order for this fog to manifest. Current
thinking based on NBM/REFS/GLAMP guidance is that winds will
taper off over the next couple of hours and allow for fog
formation. The main uncertainty with respect to the forecast is
duration of fog and how dense fog will be, so have given a
first-guess based off a combination of lower percentile members
of the REFS.

Fog likely mixes out between ~14-16Z Wednesday, with VFR
conditions likely to continue through 00Z Thursday with very
high (~80-90%) confidence. Mid-to-high level cloud deck will
continue to thicken based on HRRR model soundings ahead of an
approaching system; however, cloud bases will likely (~100%)
confidence remain above MVFR thresholds at BFD until after 00Z
Thursday. After 00Z Thursday, widespread restrictions are
plausible with rain showers and lowering ceilings at all of
central Pennsylvania`s airfields. After 00Z Thursday, there will
be a slight increase in the potential for LLWS as well given
the presence of a 40-50kt 850mb LLJ.

Outlook...

Thu...Rain showers, especially in the PM hours on Wednesday and
continuing into Thursday. Sub-VFR conditions become more likely
in showers.

Fri-Sat...Scattered to isolated rain, cloudy conditions and sub
VFR ceilings possible.

Sun...Mainly VFR, isolated rain in NW PA.

&&

.CLIMATE...
Current Consecutive Days streak without measurable rain:

10/17 through 11/3 (18 days): Harrisburg, Williamsport,
Altoona, State College

10/18 through 11/2 (17 days): Johnstown

Daily record highs for 11/4 and 11/5:

Harrisburg           78/1994 | 79/1975
Williamsport         75/2003 | 77/1994
Altoona              77/2003 | 77/2015
Bradford             74/2015 | 76/2024
State College        78/2003 | 75/2015

&&

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

&&

$$

WHAT HAS CHANGED...Steinbugl
KEY MESSAGES...Steinbugl
DISCUSSION...Steinbugl
AVIATION...Banghoff/Beaty
CLIMATE...Steinbugl