textproduct: State College

SYNOPSIS

* Snow and embedded squalls will develop tonight across parts of central PA, associated with a strong cold front * Areas of lake enhanced and upslope snow will persist into New Year's Day, along with very cold wind chills * Moderating temperatures are expected over the weekend and into next week

NEAR TERM /THROUGH TODAY/

As of mid-afternoon, we're in a relative lull across central and northwest PA, as backing flow ahead of our next incoming disturbance shunts the main Lake Erie band well north, and also effectively cuts off Lake Erie moisture to help feed lake- enhanced/upslope snow showers into the Alleghenies.

However, the break won't last long, as a digging short-wave over the northern lakes and an associated surface arctic boundary is waiting in the wings. Model guidance depicts increased westerly flow in the 925-850 mb layer this evening as these systems approach, which will enhance the upslope component into the Laurel Highlands, in addition to the general synoptic lift at play from the upper-level wave. This all points to a period of moderate-heavy snow tonight in the Laurel Highlands, with HREF guidance showing increased probabilities for 1"/hour rates between about 02z and 09z. Thus, our current Winter Storm Warning in Somerset county and high-end Advisory in Cambria county appear to be in good shape.

The other issue later tonight will be snow squall potential along the surface boundary. Good convergence along this front, unstable conditions in the upper part of the boundary layer, and decent forcing aloft point to the potential for robust linear development. We'll continue to message this threat and closely monitor conditions tonight, especially considering NYE celebrations concurrent with likely snow squall development.

NW flow lake-effect bands are also expected to kick in overnight behind the front. This scenario is well handled by our Warning in Warren and McKean counties, as well as adjacent Advisories for Potter, Elk, Cameron, and Clearfield counties.

On New Year's Day, strong cold advection and moisture off Lake Erie will continue the lake snow bands at least through the midday hours, with a gradual reduction likely in the afternoon, as the capping inversion starts to come down.

As for the snow in the Laurels is concerned, although NW flow upslope will continue to produce general snow showers, the heaviest snow should be over, as synoptic-scale upglide will be significantly less by then.

In general, it will be a cold and windy start to 2026, with -/+ single digit wind chills anticipated for most of the area.

SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/

Cold NW flow will continue this period, with brisk conditions and biting wind chills foreseen area-wide.

Although most of central PA will either be dry or just experience a few flurries, lingering lake snow bands in the northwest snow belt areas, as well as upslope snow showers in the Laurels, could bring small additional accumulations.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

In general, a break from the persistent cold/below normal temperatures is foreseen for central and northwest PA, as upper-level heights relax, and a more zonal flow regime settles in.

Fast moving disturbances could bring occasional periods of light rain or snow, but overall, no major storms are anticipated at this time.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Cold front stationed along a KIPT/KPIT line continues trucking south/eastward as of 01/06Z with observed snow squalls bringing rapid drops of visibility to central Pennsylvania's airfields for approximately 30 to 45 minutes a piece. Front still has to clear all airfields outside of BFD, thus high confidence on LIFR conditions at some point over the next 2-3 hours at all airfields outside of LNS/MDT where there remains moderate confidence as squalls potentially lose intensity further southeast. Model guidance is in fair agreement with regards to timing; however, still have slightly extended timeframe for a little bit of breathing room for the airfields. Behind the frontal passage, highest confidence in continued long-duration restrictions become limited to BFD/JST with upslope and lake effect snow showers possibly continuing through 01/12Z to 01/18Z with low-to-moderate confidence towards the end of the aforementioned timeframe. Elsewhere, higher confidence in VFR conditions are expected with brief bouts of MVFR progged by HREF/NBM model guidance after 01/15Z.

Outlook...

Fri...VFR S & E. MVFR cigs with a chance of a snow shower at BFD and perhaps JST.

Sat...Still a chance of a snow shower early at BFD, then VFR.

Sun...Mainly VFR.

Mon...Clipper system with sct/numerous SHSN W w/IFR poss. Mainly MVFR E.

CTP WATCHES/WARNINGS/ADVISORIES

Lake Effect Snow Warning until 7 PM EST this evening for PAZ004-005. Winter Weather Advisory until 4 PM EST this afternoon for PAZ006-010-011. Winter Weather Advisory until 10 AM EST this morning for PAZ017-024. Winter Storm Warning until 10 AM EST this morning for PAZ033.