Temps rise to mid-50s on unusually warm December day — but Friday snow is possible

A man bikes in Chinatown as temperatures rise into the 50s on Dec. 10, 2020. | Pat Nabong/Sun-Times

The Chicago area got a small break from pandemic-altered life Thursday in the form of unseasonably warm weather.

Temperatures hit 56 degrees at O’Hare International Airport shortly before 1 p.m., according to the National Weather Service.

Including Wednesday’s high of 53 degrees, it marks the second-straight day of 50-plus degree weather.

“We’re definitely well above normal here,” according to weather service meteorologist Jake Petr, who said the average high for early December is 36 degrees.

People enjoy temperatures in the 50s in Chicago on Dec. 10, 2020.

The reason for the warmth? A weather system has pushed cold air into Canada and allowed warm temperatures in from the south. And clear skies allowed sunlight to directly warm up the ground.

December temps in the 50s aren’t unheard of, and Thursday’s high was still far away from the record daily high of 62 degrees, Petr said.

But the sunny skies and temperate days won’t last long.

Friday evening will usher in rain, snow and cool breezes in the 30s and 40s, Petr said.

The potential for accumulating snow exists Fri night into Sat for far northern IL with better chances for accumulating snow the farther northwest you go. Uncertainty still exists over where the dividing line between rain & snow will set up, so stay tuned for updates. #ilwx #inwx pic.twitter.com/HUBkY6ndOs

— NWS Chicago (@NWSChicago) December 10, 2020

“For Chicago, this will be a mostly rain event, especially starting out,” Petr said.

Forecasters expect a “decent amount” of rain Friday night, between 1 and 1.5 inches, he said.

On Saturday, Chicago can expect a mix of rain and snow into the evening before transitioning into all snow.

But don’t expect the snow to stick for long.

Above-freezing temperatures Saturday might keep the snow at trace amounts — although the more generous forecast calls for snow up to an inch, Petr said.

There’s also a threat of strong winds and lakeshore flooding at the tail-end of the system over the weekend, Petr said.

People enjoy temperatures in the 50s in Chicago on Dec. 10, 2020.