856
FXUS61 KCTP 201219
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
719 AM EST Thu Nov 20 2025

.SYNOPSIS...
* Areas of dense and freezing fog early this morning; otherwise
  partly to mostly cloudy today becoming cloudy tonight
* Period of rain later Friday through Friday night precedes a
  drying trend over the weekend
* Mild pattern with rain prior to Thanksgiving turns decidedly
  colder with temperatures below average by next weekend

&&

.NEAR TERM /THROUGH TONIGHT/...
Areas of dense and freezing fog will result in locally hazardous
travel conditions early this morning. We`ve expanded the DFA
eastward across the central Alleghenies into the mid and lower
Susquehanna Valley based on IR sat/fog trends and sfc
(ASOS/RWIS) obs.

Fog fades by midday with partly to mostly cloudy conditions
prevailing for the rest of today. Max temps in the mid 40s are
fairly uniform across CPA and are near to slightly below late
November climo. Cloudy and a bit milder tonight (~+10F vs. last
night) with pockets of fog.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
Split stream flow aloft eventually sends a cold front through
CPA to end the week, driving a period of rain most likely from
late Friday afternoon through Friday night/AM Saturday. Some
pockets of mixed precip may be possible on the northern edge of
the precip by early Saturday morning, but differences with
model QPF placement offer significantly reduced odds/confidence.
Max temps Friday bounce 5-10F to the upside reaching the 45-55F
range.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Drying trend expected over the weekend behind the cold frontal
passage. Upper level trough pivoting through the Great Lakes may
deliver some rain/snow showers to the northern tier on Sunday.
On balance, it should be a quiet weekend with temps remaining
close to the historical average.

While the exact timing remains uncertain (typical fast/low
biases evident in the GFS/ECMWF), a period of rain appears most
likely in the Tuesday or Wednesday time frame ahead of the next
split stream system tracking eastward from the Central U.S.

Ensemble model data continues to advertise a pattern shift
toward colder/below average temperatures after Thanksgiving.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Surface high pressure centered over the Adirondack Mtns this
morning has its ridge extending south into Pennsylvania,
leading to light and variable wind and variable amounts of
high clouds streaming east across the state.

That being said, leftover low level moisture from the rain and
wet snow Tuesday night/early Wednesday has helped to create
dense fog in many locations throughout Central PA, and this fog
with LIFR/VLIFR conditions will persist until at least 13-14Z
and perhaps until around noon in some of the deeper valleys.

The fog will lift to a fairly solid layer of stratus/stratocu
this afternoon as vertical mixing only extends up to between 1.5
and 2 kft AGL with only a light SE to South wind at under 5
mph.

The best conditions, thanks to the least amount of rain over
the past 36 hours and a several deg sfc T/Td spread will
continue to be across the northern tier counties of PA with VFR
through the bulk of the day before some late mid-late PM MVFR
CIGS develop/advect NE.

Pertinent part of previous discussion...

Stratus deck will gradually expand north and eastward during
the day on Thursday, eventually reaching all TAF sites by the
middle of the afternoon. This should bring MVFR restrictions to
BFD, AOO, and UNV, while ceilings at IPT, MDT, and LNS should
remain between 3000 and 4000 feet.

Outlook...

Fri-Sat...Rain spreading northeast across the region late Friday
and continuing into the mid morning hours of Saturday with
restrictions likely.

Sun-Mon...Mainly VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 9 AM EST this morning for PAZ010>012-
017>019-024>028-033>036-041-045-046-049>053-056>059-063>066.

&&

$$

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