CHICAGO (CBS) — Keep your hat and scarf handy. You might not need them this morning, but you’ll be thankful you have them this afternoon and tonight, as temperatures are expected to drop as much as 25 degrees by Wednesday morning.

Tuesday morning started off mild, with normal mid-autumn temperatures of around 50 degrees at sunrise. Even that was a few degrees cooler than overnight, when it was as warm as 58 degrees at midnight.

Though most of the morning should stay mild, there’s a chance of rain for a few hours before noon. Winds picked up in the afternoon, bringing a blast of cold air, sending temperatures plunging below freezing, though the rain should be gone before it can turn to snow.

By sunrise Wednesday, temperatures will have fallen to about 25 degrees.

Through the rest of the week, high temperatures will not reach above the mid 30s, with lows in the 20s overnight.

After last winter’s frigid conditions, it has become popular to blame any unusually cold weather on the polar vortex. While the high temperature this time of year typically is 51 degrees, according to the National Weather Service, this week’s arctic blast is not the result of the infamous polar vortex. Instead, it is no more than a normal cold front bringing colder temperatures from Alaska.

CBS 2’s Pamela Jones reports the deep chill descending in Chicago is enough to make commuters like Adeline Celenza try to cover every slice of skin.

“I’ve got the scarf, I got the Bulls hat, I’m like very layered,” she said. “My central area is very warm.”

“It’s Chicago. What do you expect? We should be used to it, but after the vortex last year, you just never know,” Kip Golden said.

That is exactly why Kip Golden headed to Target to find some warmer gloves for himself and his son and what drew Claire Pistek to check out some better gear to help block out the cold.

“I’m looking for a new lightweight down. I have a heavier down so I’m looking for my November coat as I like to call it,” she said.