A Heat Advisory is in effect for the entire Chicago area as high temps and humidity combine to make a heat index well into the triple digits.

The heat wave comes 30 years after a deadly, weeklong heat wave in Chicago that saw temperatures as high as 106 degrees and heat indices up to 120. The heat wave, which began July 13, 1995, left more than 700 people dead from heat-related illnesses. Most of those who died were elderly, lived alone, or didn't have access to air conditioning.

Potentially harmful levels of heat and humidity could hit the Chicago area on Wednesday and Thursday with top heat indices of 105 to 115.