Heat index values will be between 103 and 108 degrees.

CHICAGO (WLS) -- Extreme heat continues to blanket the Chicago area Tuesday.
The National Weather Service has issued an Extreme Heat Warning for the entire Chicago area, which will remain until Thursday evening.
For Tuesday, high temperatures are forecast in the upper 90s with heat index values between 103-108 degrees.
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Staff at Stroger Hospital of Cook County are watching closely for signs of heat-related illness, particularly among young people and older adults. Dr. Trevor Lewis, chairman of emergency medicine at Stroger Hospital, said seniors face heightened risks.
"A lot of seniors are on a lot of medications and some of those medications blunt the body's response of trying to get rid of excess heat, so they are just very vulnerable populations," Lewis said.
City officials reiterated warnings about the dangers of extreme heat and humidity, especially given the city's history.
Lewis recalled his experience as a hospital resident in 1995, when more than 700 people died during a devastating Chicago heat wave.
"It hit everybody. I'm not sure we were very prepared for it, and it was horrible what happened," he said.
City officials said that tragedy led to significant changes in how Chicago prepares for and responds to extreme heat. Former Mayor Richard M. Daley created the Office of Emergency Management and Communication in its aftermath to improve coordination among agencies and encourage residents to check on their neighbors.
Officials are urging people to call 311 for a well-being check if they are concerned about someone. Chicago Fire Department Commissioner Annette Nance-Holt stressed the importance of looking out for others.

"My heart is not to see that happen to any family member to find out you lost a loved one failed to check on them or failed to check if they had adequate conditions in their apartment or house," Nance-Holt said.
National Weather Service Meteorologist Mike Bardou warned that high overnight temperatures could worsen the effects of prolonged heat.
"The heat index value will probably only dip below the 90-degree mark for maybe six, seven hours a night, so recovery is minimal and that's what takes the toll," Bardou said.
Mayor Brandon Johnson also urged residents to stay safe and remain aware of the risks.
"Please keep cool this week and most of all, look out for one another. OEMC and the National Weather Service will work closely together to share alerts and resources to keep you informed," the mayor said.
Lewis encouraged residents to take simple precautions to reduce their risk.
"If you are going to be out in the warm weather, hydrate first try to stay ahead so drink maybe 12-16 ounces of fluid before you go out, and maybe 6 ounces every 20-30 minutes," he said.
The best way to avoid heat-related illness and stay safe is to stay indoors and use fans and air conditioning to keep your home cool, limit your time outdoors, stay out of the sun, wear loose, light clothing and drink lots of water and fluids to remain hydrated.
The city set up cooling centers across Chicago.
People can also find relief at one of the city's public libraries, Chicago Park District fieldhouses, as well as pools and splash pads.
It's important when the temperatures climb to these extreme levels to check on your relatives, neighbors, seniors and those who are more vulnerable. You can always request a wellbeing check by calling 311.
Chicago Public Schools said their summer programming will be held inside through Wednesday.