934
FXUS61 KCTP 101136
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
636 AM EST Fri Jan 10 2025

.SYNOPSIS...
High pressure will provide the area a break from the wind and
cold today, before a fast moving storm tracking north of the
Great Lakes brings some light snow to the Keystone state late
tonight into early Saturday. Lake effect and upslope snow will
prevail across the northwest and west into Saturday night. Much
colder weather will return to the Keystone state after a brief
mild spell on Monday.

&&

.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
Ridging at the surface and aloft should provide Central PA with
dry and slightly milder weather today, along with light winds.
However, warm advection ahead of a digging upper trough over the
Grt Lks will spread thickening/lowering clouds into the area.
See no reason to deviate from NBM maxtemps, which range from the
low 20s over the Laurel Highlands, where clouds will thicken
first, to the low 30s across the Susq Valley.

&&

.SHORT TERM /5 PM THIS AFTERNOON THROUGH SUNDAY/...
Fairly strong large scale forcing is anticipated ahead of the
upstream trough tonight into Sat AM. However, moisture will be
lacking, with the deeper moisture accompanying a southern stream
wave tracking across NC and Southern VA. Weak warm advection
over PA should support a widespread light snow late tonight into
Sat AM with accumulations generally around an inch. Orographic
enhancement should result in 1-2 inches over the Allegheny
Plateau.

Light lake-enhanced upslope snow will linger over the Allegheny
Plateau later Saturday. However, Lk Erie water temps are too
cool to support lake effect, so the limited moisture source will
be from Lks Michigan/Superior. Hi-res model qpf indicates any
additional accumulations during the daylight hours of Saturday will
be generally less than 0.5 inches, but up to an inch on Laurel
Ridge west of Johnstown and Somerset.

Cold temps aloft should result in plenty of stratocu Saturday,
even across the Susq Valley, keeping temperatures a few degrees
below January normals. Expect increasingly gusty northwest winds
late Saturday, as the pressure gradient tightens west of a
deepening low off of the East Coast. Bufkit soundings support
gusts of around 25kts over the southwest part of the forecast
area by late afternoon/early evening.

Dwindling lake effect snow showers/flurries are expected Sat
night across the W Mtns, as inversion heights fall. Ridging
aloft and a developing southwest flow should result in fair and
seasonable weather Sunday. Residual lake effect stratocu and mid
level cloudiness associated with developing warm advection over
the Grt Lks should result in a mainly cloudy Sunday over the NW
Mtns. Model RH profiles support progressively brighter skies
further southeast, with mostly sunny skies anticipated across
the Susq Valley.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Mid evening update.

After a brief milder day on Monday, a return to colder than
normal weather will occur for mid week, with a gusty northwest
wind and more lake effect and upslope snow showers. Like the
current spell of cold weather, high temperatures will be more
below normal than low temperatures, given some clouds and a
gusty wind.

Earlier discussion below.

After a minor sfc ridge moves overhead Sun night, a moisture-
starved clipper is progged to move through the Great Lakes
Monday, and generate a broad light snow over the NW half of the
CWA. Then, another multi-day period of cold occurs for the early
and middle part of next week, with temperatures 10 to 20F below
climatological avgs.

The cold temps and strong west winds, with gusts 30-40 mph Tue,
will result in another period of lake effect and upslope snow.
The wind and cold will also result in some bitter wind chills
especially Tue night / Wed morning, when widespread values in
the single digits above/below 0F are expected, with some values
perhaps as low as -15F in the Laurels.

With many days of sub- freezing air for Lake Erie, ice ought to
start expanding across more of the lake by the end of the week.
As the cold persists, expanding ice should hinder the lake
effect/upslope snow machine some.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR today and early tonight with diminishing wind becoming light
and variable this afternoon and evening as high pressure builds
over the airspace.

High clouds this morning will gradually lower and thicken to
mainly MVFR tonight with light snow overspreading the region
during the middle of the night and continuing into Saturday.

Expect restrictions in the form of lowering cigs and snow
reducing visibility after 05z Sat.

Outlook...

Sat...AM light snow/IFR vsbys likely. Improvement late AM/PM.
Lake effect kicks in PM. Gusty NW flow.

Sun-Tue...Snow showers/tempo IFR vsbys possible W Mtns. Gusty
west wind Tuesday.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 7 PM this evening to 7 PM EST
Saturday for PAZ033.

&&

$$

SYNOPSIS...Dangelo/Martin
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Martin/Colbert/RXR
AVIATION...Lambert