Waves between 10 and 14 feet high are expected to flood the shores of Lake Michigan into the weekend.
The most dangerous waves are forecast for northern Cook and Lake counties, where the National Weather Service issued a lakeshore flood warning from late Friday into late Saturday.
A less severe flood watch was issued during the same period from central Cook County into Indiana.
The waves, in combination with a one-foot lake level increase, are expected to cause shoreline erosion.
“Low-lying property including parking lots, parks, paths, lawns, and structures along the immediate lakeshore will likely be inundated,” the weather service said in its advisory. “Stay dry when waves are high!”
Friday’s forecast calls for rain after 1 p.m. and a high temperature near 45 degrees, the weather service said.
Wind gusts could reach 25 mph overnight, while showers drop between 1 and 2 inches of rain.
The rain is expected to transition into snow after 4 p.m. Saturday as temperatures drop to 36 degrees, the weather service said. Little or no accumulation is expected.
Sunday is forecast to be partly sunny with a high near 36 degrees.