UPDATED 09/29/11 12:46 p.m.

CHICAGO (CBS) — A blasting wind and high waves will soon arrive in the Chicago area, as a storm system drops down from Manitoba.

Conditions were sunny and warm early in the day, but by 11 a.m., the skies had grown overcast and drizzle had begun to fall. CBS 2 Meteorologist Megan Glaros says while the high for the day was 72, a cold front is sweeping in bringing showers and thunderstorms.

Once the cold front leaves, the sun will return, but conditions will be windy and chilly from the evening hours Thursday to early Friday.

A wind advisory has been issued for the entire northern half of Illinois, as well as the entire state of Wisconsin and parts of several other states. The advisory is in effect from 4 p.m. Thursday to 5 a.m. Friday.

Winds are expected to be sustained at 20 to 30 mph, and gust up to more than 40 mph, Glaros says. If you still have deck chairs or other items outside, now is the time to secure them.

Also, reports WBBM Newsradio’s John Cody, there are still many boats moored in Chicago harbors, and it’s best to leave them there for now.

“People who are thinking about going out boating, or even captains that are thinking of taking their barges up north across the lake – people that have any sort of business, or even casual business, going out on the lake, it’s generally a good idea to not go on the lake during these types of conditions,” said National Weather Service meteorologist Sam Shea.

LISTEN: WBBM Newsradio’s John Cody reports

Waves could peak at 30 feet late in the afternoon Thursday, Shea said.

Overnight, the temperature drops to 53 degrees, and tops out at a chilly 58 on Friday with spotty showers, Glaros says. The high for Saturday is only 57, before temperatures rebound into the 60s next week.

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