Full forecast details and more at the WGN Weather Center blog
First the snow, now the cold!
Winter 2021-22’s coldest temp yet is on the way Sunday night into Monday morning
Up to now, the coldest winter temp in the city was the 13-degree low back on Dec. 7. Sunday night low temps in the city will dip into single digits.
Longer range model indications are that, while temps will gyrate with surges of above normal temps–but reinforcing cold air outbreaks which follow. By and large, temps are to remain below normal when averaged over 5-day periods through the coming two weeks.
From my National Weather Service-Chicago colleagues come these graphic on the COLD NIGHT AHEAD Sunday night into Monday morning.
What’s a High Albedo?
It’s no surprise we’re going to shiver tonight. It’s a demonstrable fact that our coldest Chicago area temps occur once a reflective cover of snow is down–as it is now. The reason for this is simple. Snow cover has a “high albedo”–which means it’s highly reflective–sunlight is reflected away from it. Thus snow preserves the bitter chill of arctic air masses which move in from the north. It’s no accident that the most frequent occurrence of single digit or sub-zero temps in any winter comes once snow is down, not only here in Chicago, but to our north as well–the source region of our coldest air.