Blame Canada.

Temperatures are expected to dip below zero for the first time this season in the Twin Cities, where it's expected to be 5 below on Tuesday morning. On Wednesday morning: Minus 10 degrees.

"It's a little unusual, we're well below normal," National Weather Service (NWS) meteorologist Caleb Grunzke said Monday night. "Basically, the upper level jet stream is bringing down cold air from northern Canada into our region."

The good news? "It's not going to last long. It will start warming up Wednesday night. But these next two days won't be fun."

The Weather Service said the high Tuesday will be 3 degrees before dropping to a low of minus 10 on Tuesday night. Windchills will be in the 22-below range. The high Wednesday will be 2, with windchills of minus 17.

The dive into the deep freeze comes after snow snarled traffic during Monday's morning commute. Monday's snow combined with a little rain and dropping temperatures turned highways and freeways slick.

In Lake Elmo, a school bus with students on board slid through a stop sign on Manning Avenue near 24th Street, where it was struck by a southbound car. No one on the bus was hurt but the driver of the car was taken to a hospital with unspecified injuries, the Washington County Sheriff's Office said.

The Minnesota Department of Transportation had plows out to scrape away the 2 to 3 inches of snow that fell across the Twin Cities. Osseo, Plymouth and Willmar declared snow emergencies. In Roseville, the police department asked motorists to "please move vehicles off of city streets so that the plows can clean up."

Temperatures will rebound into the 20s on Thursday. By Friday, it will be "a car wash day" as the mercury will hit 32 degrees, said NWS meteorologist Brent Hewett. But no extended warmth is in sight. Highs will drop back to the teens next week.

"It's the holiday season and it will be colder than we like," Hewett said.