textproduct: State College

SYNOPSIS

* Light snow accumulation likely over the western and central Alleghenies later Sat and again 24 hrs later * Reinforcing shots of cold weather and clippers provide additional opportunities for snow throughout the next 7+ days for the northwestern half of PA.

NEAR TERM /UNTIL 8 AM SATURDAY MORNING/

CLouds have done the job of keeping temps up from last night. But, they also are hanging down low enough to touch the highest ridge tops where temps are (well) below freezing. We have heard reports of FZDZ in the Laurels just to the east of Somerset Co, and we've been carrying mentions of patchy FZDZ for a while. We've tried to highlight the not-widespread threat of icy patches via an SPS (special wx statement). We will keep an eye on developments thru the night, but it is not expected to get worse than patchy icy spots.

SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/

Have tried to bring more continuity to the PoPs for Sat and Sat night. Expect -SHSN over the wrn mtns as a very weak upper short wave trough passes through. Some breaks in the clouds are possible Sat and again Sun, but many layers of clouds are expected to make it tough to find them. Some clearing is possible for the SE half Sat night.

Prev... Some fleeting sunshine possible Saturday, but don't bank on it in most places, as the exit of the aforementioned widespread stratus deck (resulting from development of a mean swrly llvl flow) is quickly replaced by a dual layer of higher based stratocu and thick layer of mid and high clouds.

The passage of a weak sfc trough will add a southwesterly breeze on Saturday, helping to push max temps closer to early December climo with highs +5-10F warmer day/day in most locations.

Highs Sat afternoon will range from 30-35 across the northern mtns to the low 40s in the southern valleys.

Lake effect snow trajectories marginally improve by Saturday night over the NW mtns (generally northern Warren and Mckean Ctys) before lowering inversion heights and backing low level winds keep light snow accums mainly confined to the I90 corridor.

Split/northern stream trough swings through on Sunday and likely brings some light (lake/terrain enhanced) snow primarily to the western and northern Alleghenies. NBM snow accum favors sub- advisory level accumulation for most areas, with the best odds for 2-3" across the NW mtns along and north of US-6.

LONG TERM /MONDAY THROUGH FRIDAY/

A cold but quiet start to next week will be followed by a reinforcing cold weather pattern as we see the exit to the east of the strong and persistent SWrly Subtropical Jet from the Baja area to the Carolina Coast.

The large scale upper flow will become more amplified for the middle to late week period with a persistent trough in the east and ridging over the Rockies and Western States.

Several clippers migrating through and reinforcing the Eastern U.S. trough will bring at least 2-3 opportunities for snow (and possibly a little mixed precip across the south).

The next, best chance for wintry precip area-wide is Wednesday/Wednesday night, as a vigorous clipper drops southeast across the region. Model consensus points toward low-end advisory category snow (3-4 inches) possible across the nrn and western mtns with an inch or so of accum in the central Ridge and Valley region associated with the several hour period of warm advection snow in advance of the upper shortwave.

The second noteworthy precip event for next week will come Friday as a similar shortwave (but with a much more southern track) spreads some snow over primarily southern PA as a northerly llvl flow with 850 mb temps in the -8 to -12C range will ensure deep cold air in place for all snow. Confidence remains high in below normal temperatures; Monday night could be another frigid period with lows -5F to +15F by daybreak Tuesday.

AVIATION /03Z SATURDAY THROUGH WEDNESDAY/

Not much change for the 00Z TAF set.

There could be isolated tiny snowflakes at times overnight, some indication of this on the radar returns on the MD/PA border as of 5 PM. MVFR to IFR CIGS across the entire area as of 5 PM as well, not seeing much change in conditions overnight. CIGS will trend to lower with time, before improving later on Sat.

See earlier information below on the potential for very light freezing drizzle with the lower CIGS over the higher terrain.

Earlier information below.

Widespread MVFR to low end VFR stratus covers all of the Central PA the mid afternoon hour. Ceilings will lower to IFR across most of central PA during the evening and overnight.

Once IFR ceilings develop, they will likely persist at BFD, JST, and LNS through 12Z Sat. The other sites may see ceilings rise to MVFR before sunrise Sat.

Some patchy light freezing drizzle is possible late today through early Sat where cloud bases lower to within 500 feet or so of the ground (which will occur mainly on the ridge tops).

Outlook... Sat...Restrictions possible, chance of snow showers in the NW

Sun...A compact but more amplified upper level trough with a preceding low level south to southwesterly wind max will likely bring a 4 to 6 hour period of mainly light snow with IFR vsbys and MVFR to IFR CIGS (targeting mainly central and northern PA) late Sunday/Sunday night.

Mon...Mainly VFR

Tue...Snow/restrictions possible mostly in the second half of the day

CLIMATE

A couple of record lows were set this morning (12/5/2025).

Location | Actual low (thru 5 PM) | Record (YEAR) ------------ ---------------------- -------------- Harrisburg | 21 | 12 (1926) Williamsport | 10 | 8 (1926) Bradford | -8 ** | 0 (2007) ** Altoona | 12 ** | 13 (1966) ** Johnstown | 8 | 3 (1966)

** record broken

CTP WATCHES/WARNINGS/ADVISORIES

None.