textproduct: State College

SYNOPSIS

* Light mixed precipitation this morning; turning breezy tonight * Potential for significant wintry mix Friday-Friday night * Mild trend this weekend followed by sharply colder conditions and strong winds to start next week

NEAR TERM /THROUGH TONIGHT/

A surge of warm air advection to the southeast of sfc low tracking across the Upper Great Lakes will result in a period of mixed precip across CPA this morning. Hires model data and low level thermal profiles favor a snow/mix/rain ptype transition from southwest to northeast through the morning.

We expanded the winter wx advisory to account for ice glaze potential across a broader area; best odds for an inch or 2 of snow remains confined to the northeast zones from Potter/Tioga through Sullivan into northern Schuylkill County.

Temperatures will rise above freezing in most areas by mid/late morning with pockets of light rain/drizzle lingering into the afternoon. Fcst max temps may be too warm in some areas given the early day wetbulb effects and solid cloud cover.

Conditions dry out by this evening with winds increasing tonight into early Wednesday morning. Tight pressure gradient/sfc pres rises in response to deepening low offshore New England will bring 30-40 mph wind gusts to the area late tonight. Model data shows a wind gust max approaching advisory criteria centered over the Poconos.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

High pressure migrates over CPA Wednesday afternoon ending the gusty winds and bringing a dry day for holiday travel.

Clouds increase into Wednesday night (Christmas Eve) as weak shortwave dives southeast from the Midwest toward the Central Appalachians. Model data indicates light mixed precip could reach the forecast area in the 06-12Z Thu timeframe with the best odds over the southwestern quadrant of the CWA.

The weather looks largely benign on Christmas Day with cloudy skies and max temps +5-10F above the historical average. High pressure ridge drifts over CPA Thursday night and channels down the east side of the Appalachians, setting the stage for an overrunning wintry mix event for Friday.

LONG TERM /FRIDAY THROUGH MONDAY/

Model and ensemble data show a solid consensus precip signal for Friday as 0.25-0.50" mean QPF encounters/overruns a retreating cold sector airmass. Confidence is increasing in a significant wintry mix event Friday-Friday night. Temps will be 5 to 15F colder on Friday (vs. Thursday/Christmas Day).

Temperatures are projected to trend milder over the weekend - peaking on Sunday 5-15 degrees above the historical average in the 40-50F range.

An arctic blast is possible by Monday following the passage of a strong cold front. There is also a signal for high winds behind the front along with lake effect snow. Fcst highs for Monday are 15 to 30 degrees colder than Sunday with wind chills in the +/- single digits.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

A mixture of wintry precip types are currently falling across Pennsylvania. Areas in northern and eastern PA will continue to experience snow through the next few hours while western and southern airfields are experiencing freezing rain or just plain rain. Expect a quick transition from freezing rain to rain once sunrise occurs over UNV, JST, BFD, and AOO. IPT has the best chance of seeing steady snow with this system as they should stay coldest the longest. MDT and LNS will likely see a few hours of rain or snow, but it will be fairly light. Once rain becomes the predominant precipitation type it will be very light in nature and visibility restrictions are likely until later this afternoon and into this evening.

Precipitation decreases in intensity after 18Z though drizzle, low clouds, and reduced visibility will linger through the rest of the day. A 45 knot low-level jet will move into southwest PA during the afternoon resulting in a period of LLWS for JST, AOO, and UNV. VFR will slowly begin to return beginning over the southeast after 00Z tonight.

Outlook... Wed...Lingering restrictions in the west, otherwise VFR with plenty of sunshine. Increasing clouds late.

Thu...Scattered rain showers, some FZRA possible.

Fri-Sat...Widespread -SN developing (with restrictions), possibly changing to sleet or a brief period of -ZR Friday night.

CTP WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 9 AM EST this morning for PAZ004- 025>028-034-035. Winter Weather Advisory until noon EST today for PAZ005-006- 010>012-017>019-037-041-042-045-046-049>053-058.