textproduct: State College

WHAT HAS CHANGED

* Cold Weather Advisory issued for most of the area tonight into early Monday morning

KEY MESSAGES

1) One more bitter cold night before frigid conditions ease for the second week of February

DISCUSSION

KEY MESSAGE 1: One more bitter cold night before frigid conditions ease for the second week of February

One of the coldest late January-early February periods on record is [thankfully] about to come to an end. To cap it off, we will have to endure one more bitter cold night/early Monday morning.

This time around, cold wx headlines are triggered based on a mix of minimum air temperatures (west-central PA) and minimum wind chills (east-central PA). The floor for min temps around KBFD is in the -20 to -25F range based on traditional GFS/MAV MOS guidance. We employed a hedged approach (blending base NBM with 5-10%tile and MAVMOS) taking into account some factors (clouds or a light breeze) that may prevent "elite" radiational cooling from playing out. That being said, we still felt leaning colder was the best bet under clear skies/calm winds with snow on the ground and 1030mb high settling right over NW PA by 12Z Monday. Cold weather advisory is in effect from 10PM tonight to 9AM Monday.

AVIATION /00Z MONDAY THROUGH FRIDAY/

High pressure will result in a very cold night, as skies will be clear and winds will continue to weaken overnight.

The big question will be if there will be short time near sunrise Monday where some haze and fog will build up near the ground, given really strong radiation cooling. Sites across the east such as IPT, MDT, and LNS may keep just enough wind to prevent any formation. I added in UNV, and AOO to have some fog late. The higher chance to see fog and hz build up will be at BFD and JST, where the temperature can drop below the fcst dewpoint. Observed soundings the last 2 days had the coldest air in the low to mid levels of the atmosphere being right on the ground.

After the sun comes up, would expect conditions to improve with just some mid and high clouds, given warm advection.

Outlook...

Tue...No sig wx.

Wed-Thu...Small chance for some very light mixed precipitation, mainly across the north. Trace amts.

Fri...Small chance for some very light snow across the south.

CTP WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 10 PM this evening to 9 AM EST Monday for PAZ004>006-010>012-017>019-024-025-033-034-037-041- 042-045-046-049>053-057>059-065-066.