CHICAGO (CBS) — CBS 2 Meteorologist Megan Glaros says we can expect “nearly perfect sunshine” Wednesday afternoon, as the highs climb into the upper 80s.

A ridge of high pressure remains dominant to the southeast, keeping skies clear and sending warm air in from the southwest.

As of 11:20 a.m., it was 78 at Midway International Airport and Waukegan, 77 at O’Hare International Airport and Gary, Ind., and 79 at Kankakee. The high for the day is 87.

But everything changes on Thursday. Following an overnight low that will drop to 62 degrees, a cold front that is now over the Great Plains states will sweep in and first bring clouds and then rain for the second half of the day.

The rain will continue Thursday night and at the start of Friday.