textproduct: State College

SYNOPSIS

* Decreasing wind, partial clearing and cold overnight. * Tranquil and seasonable this weekend with a moderating trend into Christmas.

NEAR TERM /THROUGH SATURDAY/

Surface pressure gradient and wind will gradually slacken overnight as a strong, 970 mb sfc low moves through Eastern Quebec, CA.

Mean llvl flow will remain from the NW overnight before backing to the SW later Sat morning (west) and Sat afternoon (east). Although increasingly large breaks will develop in the strato cu deck across the Scent Mtns and Susq Valley, mostly cloudy to OVC skies will persist across the NW half of the CWA with just flurries as the subsidence inversion lowers and clouds become more shallow and drop/warm out of the DGZ.

Temperatures will drop a few degrees overnight as winds taper off. As a result, wind chills likely remain fairly consistent and in the single digits north/west and teens southeast.

SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/

Temps are able to rise on Sat with most low clouds leaving the NW in the morning and only a thick shield of cirrus over the entire area for the bulk of the day. WAA should help temps up to around 40 in the far S and lower 30s in the NErn mtns. Then, a sharp but very dry cold front drops us back into winter Sat night. The front and a brief period of cross-lake flow could make some accumulating snow in the far NW, but the dryness of the airmass and short period of forcing will make any significant accumulations unlikely. The far northwest parts of Warren County are most likely to see accumulations over an inch with lesser amounts farther southeast.

It seems the best forcing along the front will be north and east of our area, with the latest snow squall parameter forecasts progged to remain below thresholds in Central PA. If any stronger snow showers do develop, it is unlikely they'll make it down to I-80 and any notable impacts to travel are unlikely. Temperatures Sunday afternoon rebound nicely in the southeast to the low 40s with temperatures in the 20s and 30s common farther north and west.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

The cold air retreats through early next week, setting up a couple potential overrunning mixed precip events for Mon night/ Tuesday and again on Christmas Eve/Christmas Day. The second system looks milder/wetter, staying mainly above freezing for a majority of Central PA - except in the NE. Timing will be critical for any winter wx impacts as max temperatures are forecast to trend above the historical average for late December. These systems should make only minor precip amounts. Neither gains any moisture until they get to the Great Lakes. They are both progged to move quickly on zonal flow aloft. With antecedent mild temperatures and no significant snowfall accumulation expected between now and Christmas, it seems the odds of a white Christmas are waning, especially for locations outside of the typical upslope/lake effect zones.

AVIATION /02Z SATURDAY THROUGH WEDNESDAY/

Bands of snow will continue to move through the western airfields through the evening, decreasing in coverage through 06Z. These snow showers will continue to cause visibility to drop to IFR at BFD, JST, and UNV as they move through. Ceilings will gradually rise to VFR through 12Z as high pressure builds in from the west. Expect winds to gust up to 45 knots for a few more hours before decreasing to less than 20 knots overnight.

A disturbance passing to our north will lead to increasing mid and high clouds during the late morning/early afternoon. A 40 to 50 knot low-level jet associated with this system will move in from the west after 18Z and will bring a period of LLWS to most TAF sites.

Outlook...

Sun...MVFR-IFR BFD in SCT -SHSN. VFR cigs favored elsewhere.

Mon...Trending drier with VFR favored. Snow enters W PA late evening with restrictions possible.

Tue...Rain/snow becomes increasingly possible, restrictions possible.

Wed...A few lingering rain and snow showers. Trending VFR.

CLIMATE

Astronomical winter (solstice) begins at 10:03 a.m. on Sunday, December 21st.

CTP WATCHES/WARNINGS/ADVISORIES

Wind Advisory until 1 AM EST Saturday for PAZ004>006-010>012- 017>019-027-028-037-041-042-045-046-049>053-056>059-063>066. High Wind Warning until 1 AM EST Saturday for PAZ024>026- 033>036.