Much of northern Illinois is expected to see over 6 inches of snow, with some regions that may see up to a foot of snow, early Friday and into Saturday. | Graphic: NWS Chicago

The National Weather Service has issued a winter storm warning for Lake and McHenry counties ahead of a winter storm expected to bring over 6 inches of snow, 40-50 mph wind gusts and bitter cold.

The National Weather Service (NWS) in Chicago issued the warning Thursday afternoon for all of northern Illinois.

The warnings for Lake and McHenry counties will expire at noon on Saturday.

The “significant winter storm” is expected to bring 6-8 inches of snow to Lake and McHenry counties, the NWS said.

Snow will begin in the early morning hours of Friday and continue into Saturday.

The highest snowfall rates for Lake and McHenry counties are expected for a couple of hours after 5 a.m. Friday and much of that afternoon and into the evening.

A winter storm early Friday and into Saturday will affect northern Illinois, with the heaviest snowfall expected Friday morning and for much of the afternoon and evening. | Graphic: NWS Chicago

Blizzard conditions are possible Friday evening and Saturday, with northwest winds gusting 40-50 mph.

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Wind chills of -10 to -30 degrees Fahrenheit are expected Sunday morning through Wednesday.

The NWS urged motorists to avoid travel if possible.

“Travel will be very difficult across most of the area tomorrow,” the NWS said.

“If it cannot be avoided, however, and you must travel, please take the time to make sure that your car has plenty of gas and a fully stocked emergency kit. And use extra caution when driving in adverse weather!” the NWS added.