The region recorded the lowest temperatures in early December in years Tuesday, and forecasters said it is only going to get worse Wednesday.
O'Hare International Airport on Tuesday morning recorded the first below-zero temperature — minus 6 — in the first 10 days of December since 1995, said Richard Castro, meteorologist with the National Weather Service in Romeoville, Ill.
Valparaiso and Rensselaer recorded temperatures of 1 below zero, the lowest for the start of December since 2005, Castro said.
The cold weather is expected to continue through Thursday, with highs in the teens and lows in the single digits or below zero. Wind chills could drop to as low as 20 below zero.
Snow was expected after midnight Tuesday, creating a potentially hazardous commute Wednesday morning.
Lake, Porter, Cook and Will counties are under a winter weather advisory until 10 a.m. Wednesday. The forecast calls for snow to spread east with as much as 2 to 4 inches of accumulation possible.
The system is expected to peak in the region between 4 and 8 a.m. with accumulation of as much as half an inch per hour possible.
Castro said cold temperatures are expected to make road salt less effective.
"With temperatures being really cold as the snow is falling, it's going to be causing problems for the road crews trying to keep the roads clear," Castro said.
The National Weather Service issued a special weather statement for LaPorte County, where only 1 to 3 inches of accumulation were expected there by early Wednesday morning.
Winds in LaPorte County are expected to increase to 10 mph to 20 mph Wednesday afternoon, which could create hazardous driving conditions, according to the National Weather Service.
Castro said Friday and Saturday should bring some relief from the bitter cold, with highs near 30, but another system pushing through the region could bring "decent precipitation, possibly 2 to 4 inches" Friday night into Saturday.