The National Weather Service has issued an urgent blizzard warning on Sunday for portions of Northern Illinois and Northwest Indiana.

The major snowstorm, which is predicted to bring around 18 inches of snow, is expected to impact the region by Tuesday and Wednesday.

The first phase of the upcoming winter storm will begin Monday afternoon and continue into Tuesday morning for portions of Northern Illinois and Northwest Indiana. The focus then turns towards the larger event beginning Tuesday afternoon and continuing through Wednesday, the warning issued by the weather service states.

As much as 12 inches of accumulation is expected in parts of North Central Illinois while over 18 inches are predicted for Northeast and East Central Illinois as well as Northwest Indiana.

Due to extreme weather conditions and snow accumulation, officials are warning those travelling through Chicago O'Hare and Midway Airports to continue monitoring later forecasts to check the development of the storm.