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.

308
FXUS61 KCTP 201731
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1231 PM EST Tue Jan 20 2026

.WHAT HAS CHANGED...
* Increased expected snowfall amounts for Wednesday night into
Thursday, prompting the issuance of a Winter Storm Watch for
Cameron, Clearfield, Elk, McKean, Potter, and Warren County
from 12PM Wednesday to 10AM Thursday.

&&

.KEY MESSAGES...
1) Dangerous, sub-zero wind chills gradually rise this morning;
warming trend continues through Thursday afternoon.

2) Quick-hitting winter storm to bring a heavy thump of snow
and localized accumulations >4-6" in northwest PA on Wednesday
afternoon into Thursday morning.

3) Monitoring the track of a significant winter storm this
weekend; highest impacts will remain south of PA, but northward
extent of accumulating snowfall remains uncertain.

4) Frigid temperatures return this weekend and
likely stay around until the end of January.

&&

.DISCUSSION...
KEY MESSAGE 1: Dangerous, sub-zero wind chills gradually rise this
morning; warming trend continues through Thursday afternoon.

Numerous locations across the Alleghenies have reported wind
chills of -10F or lower this morning, with temperatures near
zero west of I-99 and north of I-80 and in the single digits
southeast toward the I-81 corridor. Wind will remain a bit gusty
today before high pressure builds in tonight. A Cold Weather
Advisory remains in effect until midday with dangerous wind
chills expected to continue this morning.

As high pressure builds in and moves just southeast of PA
tonight, winds will taper off and one more cold, clear night is
expected with lows in the single digits areawide. High pressure
moves off the coast on Wednesday, bringing gusty southerly
winds. In the summer time these winds would be refreshing, but -
despite bringing moderating temperatures - they`ll keep wind
chills in the teens and 20s all day on Wednesday. Additional
"warming" is expected for Thursday ahead of a cold front as
highs trend a few degrees above normal in southeast PA.

KEY MESSAGE 2: Quick-hitting winter storm to bring a heavy thump
of snow and localized accumulations >4-6" in northwest PA on
Wednesday afternoon into Thursday morning.

After a brief dry period, snow chances return to parts of the
region late Wednesday into Thursday as deep layer WAA develops
at the nose of a potent 50-60 kt llvl southwesterly jet and
beneath the right entrance region 80-90 kt 500 mb jetlet - ahead
of the next shortwave rotating through the persistent trough
over the eastern US. The typical lake effect and upslope snow
regions of the Alleghenies in Western PA will once again be
favored as the surface low is expected to pass well to our
north.

The latest medium-range guidance highlights the potential for
several hours of snow rates of 1 inch per hour or greater
Wednesday evening in the northwest mountains. This could lead to
rapidly deteriorating road conditions and a quick accumulation
of 4"+ of snow. Based on an increasing probability of snowfall
amounts over 6", we decided to issue a Winter Storm Watch for
the northwest batch of counties. Snowfall amounts will cut off
rather quickly with southeastward extent, and little to no snow
is expected east of I-99 or south of I-80.

There may be a lull in the snowfall early Thursday morning
before another strong Arctic front helps invigorate scattered to
numerous snow showers and squalls on Thursday. The setup may end
up being similar to Monday, though current guidance keeps the
threat a little bit farther north. Regardless, anyone one with
travel plans in northwest PA on Wednesday afternoon through
Thursday morning should monitor the forecast for additional
updates. Temperatures will drop off quickly Thursday night,
dipping back into the single digits in the northwest mountains.

KEY MESSAGE 3: Monitoring the track of a significant winter
storm this weekend; highest impacts will remain south of PA,
but northward extent of accumulating snowfall remains uncertain.

This weekend, a strong 500mb trough will dig into the Central US
over top of anomalously frigid Arctic air. Meanwhile, a surface
low will develop across the southern Plains ahead of an
advancing southern stream trough paving the way for a
potentially significant winter storm from Oklahoma to Virginia.
Importantly, the right entrance region of the 500mb jet is
progged to overlap with the left exit region of a jetlet
ejecting from the aforementioned southern stream shortwave,
creating ideal lifting conditions for heavy snowfall in the mid
Atlantic Saturday night into Sunday. There are subtle
differences in timing among the suite of ensemble guidance, but
confidence is increasing in at least light snowfall accumulation
all the way up to I-80. The highest snowfall amounts in our area
will likely be in southeast PA, with specific totals contingent
on the track of the storm. Stay tuned for updates to the
forecast!

KEY MESSAGE 4: Frigid temperatures return this weekend and
likely stay around until the end of January.

A sprawling ridge of high pressure will move into the lower 48
on Saturday in the wake of a strong Arctic front. This system
will usher in a period of frigid air with temperatures as much
as 30 degrees below average in the climatologically coldest part
of the year. Highs on Saturday may struggle to make it out of
the single digits at higher elevations across northern and
western PA. The long range pattern favors a persistent eastern
US ridge, which should keep below normal temperatures firmly in
place through the end of the month. The Climate Prediction
Center has placed much of Pennsylvania in a rare High Risk of
Much Below Normal Temperatures for Tuesday January 27 - Friday
January 30th. A couple storm systems may bring gusty winds,
which would exacerbate wind chills and could necessitate
additional Cold Weather Advisories or Extreme Cold
Watches/Warnings.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Mostly clear skies are present across all of central
Pennsylvania this afternoon outside of a broken deck of clouds
across the northwestern airfields. Wind gusts of 20 to 25 knots
continue through the day before decreasing overnight. VFR will
dominate the airspace for the most part for the next 24 hours
with little in the way of sky cover for the remainder of this
afternoon. Mid and high clouds increase from the west after 06Z
ahead of an approaching low pressure system.The next chance of
perception will arrive late Wednesday afternoon across the
northwest. A prob30 group has been introduced for BFD to outline
the possible onset of snow.

WED...Snow/IFR NW in the afternoon, MVFR-VFR elsewhere.

THU...CFROPA, gusty. LIFR/IFR cigs/vis in SHSN N & W, MVFR cigs SE.

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

SAT...Widespread SN/IFR possible, esp S.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Wednesday afternoon through Thursday
morning for PAZ004>006-010-011-017.
Cold Weather Advisory until 1 PM EST this afternoon for PAZ017-
024-033.

&&

$$

WHAT HAS CHANGED...Banghoff
KEY MESSAGES...Lambert/Banghoff
DISCUSSION...Lambert/Banghoff
AVIATION...Bauco/Bowen

Forecaster's
Discussion: