Forecasters are warning of the potential for a major winter storm that could leave as much as half a foot of snow on the ground Thursday, create hazardous driving conditions and impact air travel in Chicago.
The National Weather Service issued a special weather statement for Cook, Will, Lake, Porter, Jasper, Newton and Benton counties Tuesday.
A rapidly strengthening winter storm is expected to approach the region Wednesday night, tracking across northern Illinois and Northwest Indiana on Thursday. Forecasters said rain is expected to develop ahead of the system and change into all snow in Illinois by midday Thursday and Northwest Indiana by Thursday afternoon.
The heaviest snow is expected to accumulate in northwest Illinois, north central Illinois and Wisconsin, where up to 6 inches of snow are possible.
But forecasters warned Tuesday the storm was still developing and volatile. If the system moves southeast, Chicago, the south suburbs and Northwest Indiana could see greater snowfall totals.
The National Weather Service said it is "highly likely" that northwest winds will become strong Thursday afternoon and evening, with gusts as high as 45 to 50 mph. Where snow does occur, forecasters said the strong winds will lead to significant blowing and drifting snow and severely reduced visibilities.
The National Weather Service warned anyone planning to travel across the Midwest on Wednesday night through Thursday night to prepare for difficult travel. The system also could significantly impact air travel at O'Hare International and Midway airports, forecasters said.