A winter storm warning is in effect for McHenry County until 6 p.m.
Snow will develop this morning and will occasionally fall very heavily, according to the Nation Weather Service.
Accumulation from four to eight inches is possible, with isolated amounts near 10 inches.
Snowfall rates in some areas may reach two to three inches per hour, which will cause roads to be snow covered and will make travel extremely difficult, the weather service said.
The snow will taper off by early this evening.
Motorists should take caution when driving, especially this afternoon when conditions are expected to be the worst.