CHICAGO -- The winter storm heading toward Chicago has already prompted airlines to cancel more than 400 flights at the city's two airports.

The Chicago Sun-Times reports that expected to start falling on Monday afternoon at about 3 p.m. and the National Weather Service says as much as six inches could fall by late Monday night. The timing of the snowfall has the weather service warning motorists heading home after work Monday to take it slow on snowy roads and expect their drive to take longer than usual.

Temperatures were in the single digits Monday morning and the weather service is only expected them to climb to about 18 degrees on Monday.

More snow is expected much of the work week.