textproduct: State College

SYNOPSIS

* Cold Super Moonset ends of one the coldest nights on record for early December; max temps stay below freezing today * Light snow accumulation likely over the western and central Alleghenies later Sunday through Sunday night * Reinforcing cold weather pattern and clippers provide additional opportunities for snow next Tuesday-Friday

NEAR TERM /THROUGH TONIGHT/

Baby, it's cold outside. A perfect night and early morning for the Cold Super moonset around 8:20 AM. Daily record low smashed at KBFD down to -5F at 08 UTC with more room to the downside with -8F dewpoint. A low temp below -5F would rank as the 3rd coldest on record between Dec 1-5; below -7F would rank as the 2nd coldest. Several locations across the northwest 3/4 of CPA will see min temps bottom very close to daily record lows. A veil of mid/high clouds associated with a weak low sliding off the Southeast coast is preventing the bottom from falling out on min temps across the Lower Susquehanna Valley/areas near and SE of I81; unless skies can clear - the record low at KMDT not be tied or broken.

Primary stripe of snow - driven by a combo of low level fgen forcing, isentropic upglide, and jet-induced lift to the northwest of the aforementioned sfc low - stays south of the MD line. So while most of CPA will start the day sunny and very cold/frigid, look for cloud cover to expand northward by the afternoon. Given the record to bitter cold start and increasing clouds, max temps are fcst to remain below the freezing mark (32F) which is actually a pretty rare occurrence this early in the winter season.

Hires models and "goal-post" sounding profiles suggest that the expanding and low cloud deck beneath a strong inversion may be capable of producing some patchy freezing drizzle or snizzle later today and tonight - something to monitor going forward. The clouds may also add a few degrees to min temps currently fcst in the 20-25F range (much warmer than this morning!)

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Passage of weak sfc trough will add a SWly breeze on Saturday helping to push max temps closer to early December climo with highs +5-10F warmer day/day in most locations. Lake effect snow trajectories marginally improve by Saturday night over the NW mtns 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 1-3/2-4" across the NW mtns along and north of US-6.

LONG TERM /MONDAY THROUGH THURSDAY/

A cold but quiet start to next week will be followed by a reinforcing cold weather pattern with clippers providing at least 2-3 opportunities for snow. Confidence remains high in below normal temperatures; Monday night could be another frigid period with lows -5F to +15F by daybreak Tuesday.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

Current satellite shows stratus developing over southern PA. These clouds will continue to expand northward through the morning, eventually reaching all TAF sites. Ceilings will initially drop to MVFR as these clouds move in, but most guidance continues to indicate that further reductions to IFR are likely across most of central PA during the evening and overnight. Once IFR ceilings develop, they will likely persist at BFD, JST, and LNS through the rest of the 12Z TAF period. The other sites may see ceilings rise to MVFR before sunrise.

Model soundings show a fairly deep saturated layer below the dendritic growth zone late this morning and during the afternoon, which could support patchy freezing drizzle. Confidence on this occurring remains too low to include in the TAFs at this point.

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

Cold temperatures in the wake of the Arctic Front will bring frigid temperatures to central Pennsylvania, the coldest of this winter thus far. Multiple locations across the area will be challenging record low temperatures on December 5th:

Location|Record Harrisburg | 12 (1926) Williamsport | 8 (1926) Bradford | 0 (2007)** Altoona | 13 (1966)*

** record broken * record tied

CTP WATCHES/WARNINGS/ADVISORIES

None.