DETROIT (AP) — Southern Michigan braced Tuesday for bitter cold and new waves of snow expected to arrive this week.

Temperatures in Detroit dropped from the low 30s Tuesday morning to around 20 degrees mid-afternoon. Tuesday night's Detroit low was expected to be 3 to minus 3, with a high Wednesday of 11-15.

The National Weather Service expects one to three inches of snow to fall in the Detroit area on Wednesday, said Phil Kurimski, a senior meteorologist at the service's White Lake Township station in Oakland County.

More than an inch of snow fell in the Detroit area early Tuesday, leaving roads slippery for the morning rush hour. AAA Michigan responded to 1,450 motorists across the state Tuesday morning, mostly to assist with dead batteries, spinouts and minor accidents, said spokeswoman Nancy Cain.

Cain says crews expect to be busy this week as the extreme cold settles in.

In the Upper Peninsula, the service says the coldest air of the season has arrived and temperatures are expected to remain frigid for the rest of the week. The service says the mercury will bottom out as low as 20 to 25 below zero Thursday night.

In Grand Rapids, police have declared an extreme cold weather alert starting Wednesday. Police and fire crews in Michigan's second-largest city plan to visit spots frequented by the homeless, such as highway underpasses, and ask them to come to a shelter for protection.

"We don't want anyone in jeopardy," city police Lt. Ralph Mason told The Grand Rapids Press. "We're going to find a way to help."

In Detroit, city officials will open two recreation centers as daytime warming stations starting Wednesday.

DTE Energy Co. said customers likely would see a 10 percent increase in their heating bills this year over a typical winter.

"If we have colder than normal (temperatures), that means usage will be up, escalating bills higher," spokesman Scott Simons told The Detroit News.