Excessive Heat Warning Issued

The National Weather Service has issued an excessive heat warning for all of northern Illinois until 10 p.m. Friday.

The forecast high temperature on Thursday is expected to be about 103 degrees, with a heat index of 108 to 118 degrees. Temperatures are forecast to reach 102 on Friday.

"An excessive heat warning means that a prolonged period of dangerously hot temperatures will occur," according to the National Weather Service. "The combination of hot temperatures and high humidity will create a dangerous situation in which heat illnesses are likely. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors."

The July 4 temperatures were near record-breaking in Chicago. The high temperature at Chicago-O'Hare was 102, which tied the record high set in 1911. One of the highest temperatures recorded on July 4 was 104 degrees in Waukegan.