Latest Area Forecast Discussion for Central PA

Here is the latest Area Forecast Discussion for Central PA

This text statement is the latest forecast reasoning from the NWS in State College, PA

See the links at the bottom of the page for previous issuances/versions of the statement as well as our other text statements.

941
FXUS61 KCTP 212011
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
311 PM EST Wed Jan 21 2026

.WHAT HAS CHANGED...
* The Winter Weather Advisory has been expanded to include
Southern Centre, Southern Clinton, Blair, and Somerset Cos.
* Increasing potential for heavy snow and moderate to major
winter storm impacts Saturday night through Sunday night

&&

.KEY MESSAGES...
1) Quick-hitting snowfall to disrupt travel through the
Wednesday evening commute along & west of I-99/US-220

2) Increasing odds for heavy snow and moderate to major winter
storm impacts Saturday night through Sunday

3) Arctic blast with frigid temperatures and sub-zero to
dangerous wind chills expected from late week through the
weekend into the first part of next week

&&

.DISCUSSION...
KEY MESSAGE 1: Quick-hitting snowfall to disrupt travel through
the Wednesday evening commute along & west of I-99/US-220

Radar and model trends would suggest and earlier end to the
accumulating snow the NW mtns (tapering to light snow or patchy
fzdz) with main surge of snow now focused along SWly LLJ/max
pwat axis pointed across the Laurel Highlands into the south
central Alleghenies. Snow was able to overcome very dry air near
the ground and will likely make for a slippery late afternoon
and evening commute particularly near and NW of the I-99/US220
corridor. We expanded the winter wx advisory a bit farther to
the south and east earlier today to account for the shift in
the snowfall and expected travel impacts around the evening
commute.

Snow intensity/rates taper off into tonight with pockets of
light snow or fzdz into early Thursday morning as higher level
moisture peels off to the northeast. This could make for
slippery spots overnight into the Thursday morning commute.

KEY MESSAGE 2: Increasing odds for heavy snow and moderate to
major winter storm impacts Saturday night through Sunday

Confidence continues to increase in the potential for heavy
snow and moderate to major winter storm impacts across central
PA this weekend. As is often the case, the primary model
uncertainty differences center around the interaction between
the northern and southern branches of the jet stream which will
ultimately steer the storm track and associated placement of
winter wx/max snowfall. Latest models have doubled-down on the
northward trend that was very evident in the previous 21/00Z
model cycle. Big ? remains will that trend hold or will there be
a reversion back to the south.

What we know at this juncture:
1. Ptype should be all snow as arctic air remains locked in
place

2. Most likely timing for heavy snow is Saturday night
through Sunday night

3. Odds of >6" and >12" of snow have trended higher (maximized
over south central/southeast PA) with an increasing risk for
moderate to major winter storm impacts this weekend

What we don`t know yet:
1. Exactly when, where and how much snow will fall

KEY MESSAGE 3: Arctic blast with frigid temperatures and sub-
zero to dangerous wind chills expected from late week through
the weekend into the first part of next week

Initial shot of Arctic air will arrive on Friday and will be
reinforced through the weekend into next week. The frigid to
much below normal temperatures are expected to continue through
the end of January.

Sub-zero to dangerous wind chills are most likely Friday night
into Saturday morning (preceding the winter storm) and again
Monday night into Tuesday morning. Cold wx advisory or extreme
cold warnings may be needed.

The arctic air would favor a dry, fluffy snowfall over the
weekend and be more prone to blowing/drifting impacts.

Given the prolonged nature of the cold, we may begin to see
more infrastructure impacts (frozen pipes, for instance) by next
week.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Overcast skies are continuing to build in ahead of the arrival
of snow from the west. VFR conditions will continue until
precipitation begins to fall. Most guidance shows snow
beginning to fall at BFD between 18Z and 20Z, and at JST by
21Z. Current radar is showing reflectivity returns over the
northwestern airspace, but the air at the surface is too dry for
snow to reach the ground just yet. The HRRR and RAP also show
steady snow impacting AOO and UNV after 21Z. Some snow is
possible as far as east as IPT, but low level dry air should
limit its intensity. MDT and LNS will likely remain dry. Sites
that see steady snow will see IFR/LIFR visibility and BFD and
JST will likely have IFR ceilings as well.

Winds have increased into this afternoon to 10 to 15 knots. An
approaching 50-60kt LLJ will lead to LLWS at all TAF sites this
afternoon and evening.

Snow mixes with or changes to freezing drizzle this evening,
leading to improving visibility. Wind gusts also increase
overnight, with gusts of 20 to 25 knots possible. Heavier snow
showers redevelop over northwest PA late tonight and may move
through BFD prior to 12Z. These snow showers would likely cause
brief periods of IFR visibility.

Thu...CFROPA, gusty. LIFR/IFR cigs/vis in SN N/W, MVFR cigs SE.

Fri...Gusty W wind. Lake effect BFD (ocnl IFR). Mainly MVFR
elsewhere.

Sat-Sun...Dry to begin Sat. SN begins to enter south-to-north
late Sat continue through Sun. IFR possible, most likely S PA.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM EST Thursday for
PAZ004>006-010>012-017>019-024-025-033-045.

&&

$$

WHAT HAS CHANGED...Steinbugl
KEY MESSAGES...Steinbugl
DISCUSSION...Steinbugl
AVIATION...Bauco/Bowen

Forecaster's
Discussion: