textproduct: State College

SYNOPSIS

* A period of accumulating, light to moderate snow will occur into the middle to latter part of the night. Heaviest snow will be over the Laurel Highlands and over in Lancaster and York counties. * Arctic blast with locally heavy lake effect and upslope snow across western PA Sunday and Sunday night. * The wind will be gusty, leading to potentially dangerous wind chills when combined with the cold air Sunday. * A period of milder conditions is expected for the middle of the week ahead, before colder conditions for late week.

NEAR TERM /THROUGH TONIGHT/

As of early afternoon, some patches of light snow at times noted by radar. The wind shift line pushing into western NY at the current time.

Timing of the more steady snow with the strong jet dynamics still looks to push into the western mountains by late afternoon and overspread the east during the evening hours.

As noted above, snow will overspread the east this evening. Did edge snow amts up across the far southeast a bit near the MD, PA border but still in the advisory level. The system is moving fast, and will be just east of the area around sunrise.

SHORT TERM /SUNDAY THROUGH MONDAY/

A strong upper level trough will swing across the region on Sunday, with strong cold advection and increasing winds.

Weather and POP grids similar to earlier fcst. Wind gust to around 40 mph likely over the higher elevations. Temperatures on Sunday will be similar to the last few events, where daytime temperatures will not change much. Max temps Sunday will drop by 10-20 degrees vs. Saturday with mean departures from climo on the order of 15 to 25 degrees. A few locations could see highs close to the daily record low max. Across the higher spots in Somerset County and perhaps isolated spots elsewhere across the higher elevations, cold weather products might be needed. Still a ways out.

Lake effect/upslope snow showers continue through Sunday night into Monday. A weak system passing to the north could bring a few more snow showers to the area later Monday.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

A large scale pattern shift will support a west to southwest flow of milder air into the area by later Tuesday into Thursday. Some spots will have readings in the 40s.

A cold front by Friday will edge things back down some, but not the really cold that has been typical this month so far. The month has been nearly 10 degrees colder than normal up to this point, which is nearly half of December.

Always need to watch the precipitation type and timing with such a pattern. Weather systems will moving at a fast clip.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Storm with widespread snow is moving in from the west. Spotty light SN has been affecting the western terminals this aftn. Expect a decrease to IFR for JST and BFD by 23Z. The worst of the wx at JST will be between 00-04Z. AOO/UNV/IPT will have just brief forays into IFR with perhaps (40%) just an hour or so of LIFR during 03-07Z, getting back up to MVFR by 09-10Z.

MDT and especially LNS will arguably have the worst conditions tonight with snow developing and dropping conditions to IFR by 01Z. LIFR may last 4-6 hrs with the worst conditions there between 03-08Z. One inch per hour snow rates with <1/4SM are almost certain (80%) during an hour or two during that time frame. Snow clearing and deicing will be of utmost importance during that time. The end time of the snow and L/IFR will be within and hour of 10Z at MDT and 12Z at LNS. Lake effect snow then ramps up on Sunday. That puts the usual suspects of BFD and JST back down to LIFR for brief times later Sunday and all through Sunday night. A broad, heavy band of snow will point from the Great Lakes down into JST Sunday night.

Much of the area will be MVFR/VFR on Sunday and Sunday night. But, wind will be gusty out of the WNW. The worst gusts will be Sun aftn. Weak, fast shortwave trough passes on Monday, snow stays mainly in NY.

Outlook...

Mon...MVFR w/SCT SHSN N (BFD), --SN poss elsewhere.

Tue-Wed...No sig wx.

Thu...Widespread rain reducing conditions to IFC. May end as a brief period of snow in the W.

CLIMATE

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

CTP WATCHES/WARNINGS/ADVISORIES

Lake Effect Snow Warning until 7 AM EST Monday for PAZ004-005. Winter Weather Advisory until 7 AM EST Monday for PAZ010-017- 024-033. Winter Weather Advisory from 7 PM this evening to 8 AM EST Sunday for PAZ065-066.