050
FXUS61 KCTP 222323
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
623 PM EST Wed Jan 22 2025

.SYNOPSIS...
*An approaching clipper will bring increasing cloud cover to the
 Commonwealth this evening and into Thursday.
*Lake effect and upslope snow showers possible beginning late
 Thursday and into Friday, brining generally light accumulations
 topping out across northwestern Pennsylvania.
*Temperatures trend towards average this weekend and into the
 beginning of next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
Warming this afternoon has been hindered by a deck of mid-
level clouds, currently stationed along a line extending from
KSYR southwestward towards KCRW. This slight obscuration from
peak- heating continues to suggest that MaxTs to top out near 10
degrees across the coldest pockets of northern Pennsylvania to
near 18-19 degrees in the Lower Susquehanna Valley in the next
couple of hours before steadily decreasing after sunset.

The bulk of model guidance continues to indicate southerly flow
along with the aforementioned mid-level cloud deck, that will
limit potential for dangerously cold wind chills, with minimum
wind chills stationed across the valleys of northern PA along
with the Laurel Highlands. Winds are expected to be generally
light during the overnight period, which is expected to minimize
wind chill concerns outside of the northern tier where
increasing winds later in the overnight period will allow for
some minimum wind chills approaching -5F to -10F. Similar
forecast wind chills are expected in the Laurel Highlands;
however, no headlines are expected at this time due to Ts/WCs
being well above criteria at this time.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
A slight warming trend emerges on Thursday and throughout the
short-term, especially compared to the recent cold temperatures
that have been observed across central Pennsylvania. The bulk of
model guidance does suggest some clearing out of the cloud deck
during the late morning/early afternoon hours across the Lower
Susquehanna Valley, with drier air in recent RAP model soundings
also supporting these notion. This will allow for a brief
period of maximum insolation, with MaxTs pushing closer to the
upper 20s. Further west, a persistent cloud deck is expected to
limit this potential with MaxTs in the lower 20s. In terms of
MaxTs on Friday, generally the same pattern is expected,
although Ts might push +1-2 degrees compared to Thursday.

Initially dry conditions at the beginning of the short-term are
not expected to persist with southwesterly flow turning more
westerly Thursday evening, allowing for some lake effect and
upslope snow across our western zones. Have tapered back PoPs
across both NW PA and the Laurels given two reasons: 1) Lake
Erie is becoming increasingly frozen which will limit lake
effect potential across Warren (and to an even larger extent,
McKean) County and 2) moisture will be lacking, partially due to
the cold, dry air that has remained in place over the past
couple of days and that will continue to remain. Given these
notions, have tapered back on NBM by blending with CMCreg in the
Thursday evening into Friday timeframe which outlines Chc
across the furthest NW reaches of Warren County and the favored
upslope areas of the Laurel Highlands. Any precipitation is
expected to be snowfall, with generally light accumulations
topping out in the 1-2" range across Warren County. Winds begin
trending back towards southwesterly late Friday evening,
allowing for less potential for precipitation later in the
period.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Large scale flow pattern supports clippers dropping southeast
across the Great Lakes next week. The warm waters of the Great
Lakes will likely result in high centers splitting into two
sections, with the coldest air staying north of the lakes. Thus
we will see temperatures closer to normal. With the overall
pattern and snow cover, will be hard to see any extended mild
snaps.

Upper level troughs and wind shift lines will support some snow
showers from time to time into late Sunday, mainly across the
far northwest.

A clipper dropping southeast by mid week may support more snow
a bit further east and south.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
There is high confidence in VFR conditions continuing through
the 18Z TAF period as high pressure over Central PA begins to
shift to the east. Mid and high clouds will increase in
coverage during the afternoon and evening as warm advection
increases ahead of a moisture-starved disturbance approaching
from the west. Model soundings suggest that much of this cloud
cover will dissipate during the day on Thursday and partly
cloudy to mainly clear skies are expected after 12Z.

Winds will shift to the west-southwest Thursday afternoon which
will lead to clouds developing at BFD and JST. Moisture will be
very limited, at least initially, so not expecting any snow
showers prior to 18Z. Model RH profiles do suggest that lower
ceilings develop during the late afternoon and a few lake effect
and upslope snow showers could lead to visibility restrictions
at BFD and JST into the evening.

Outlook...

Thu Night...Restrictions possible at BFD and JST with -SHSN.

Fri...MVFR/IFR conditions possible with -shsn in northern &
western PA mainly during the day.

Sat...VFR/no sig wx.

Sun-Mon...MVFR in -shsn possible in northern & western PA.

&&

.CLIMATE...

A record low temperature of -11 degrees was set at Altoona, PA
last night. The old record was -5 degrees set in 1984.

A record low temperature of -11 degrees was set at Johnstown,
PA last night. The old record was -9 degrees set in 1984.

A record low temperature of -18 degrees was tied at Bradford,
PA last night. The previous record low temperature date was
2022.

Record low maximum temperatures for January 22:

Harrisburg    14F in 2014
Williamsport  14F in 1961
Altoona       10F in 2014
Bradford       6F in 2014
State College  7F in 1936

&&

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

&&

$$

SYNOPSIS...NPB
NEAR TERM...Evans/NPB
SHORT TERM...NPB
LONG TERM...Martin
AVIATION...Bauco
CLIMATE...Steinbugl