National Weather Service officials are expecting dangerous hot conditions midweek in portions of Illinois as the heat index may reach up to 115 degrees Wednesday and Thursday.

A heat advisory for Tuesday was canceled but a heat watch is now in effect starting Wednesday evening to Thursday evening, officials said.

The excessive heat warning was issued for 11 a.m. until 9 p.m. Wednesday for Boone, DeKalb, Kane, Kendall, Grundy, Kankakee, Iroquois, and Will counties. An excessive heat watch is in effect from Wednesday evening to Thursday evening, officials said.

FEMA officials cautioned of the upcoming excessive heat.

“Nearly our entire region will experience at or near historic high temperatures this week, but high heat index values will make for an extremely dangerous situation for many residents,” said Tom Sivak, FEMA Region 5 regional administrator in a statement. “We all need to take precautions. Regularly check yourself and those you care about — especially children, older adults and pets — for the signs and symptoms of heat-related illnesses and be ready to respond to them.”

Temperatures Tuesday are expected to hit 80 degrees, but a high of 96 is expected Wednesday.

Extreme heat combined with humidity increases the chance for heat-related illness, and officials recommend monitoring the latest forecast and warnings. Officials recommend drinking plenty of fluids and staying in air-conditioned rooms. Young children and pets should not be left unattended in vehicles as temperatures in vehicles could reach lethal levels within minutes, officials said.

Officials encourage checking on elderly relatives and neighbors during the expected heat wave, and be mindful of cooling centers in your area.

The Office of Emergency Management and Communications list Chicago cooling centers at six community service centers:

• Englewood Center — 1140 W. 79th St.
• Garfield Center — 10 S. Kedzie Ave. (24 Hours)
• King Center — 4314 S. Cottage Grove Ave.
• North Area Center — 845 W. Wilson Ave.
• South Chicago Center — 8650 S. Commercial Ave.
• Trina Davila Center — 4312 W. North Ave.

Additional locations will be opened from 8:30 a.m. to 4:30 p.m. Wednesday and Thursday at the following locations:

• Southeast — 1767 E. 79th St.
• Southwest — 6117 S. Kedzie Ave.
• Central West — 2102 W. Ogden Ave.
• Northeast — 2019 W. Lawrence Ave.
• Northwest — 3160 N. Milwaukee Ave.
• Renaissance Court — 78 E. Washington St. (10 a.m. — 5 p.m.)

Satellite Senior Centers

• Pilsen — 2121 S. Morgan St.
• West Town — 1615 W. Chicago Ave.
• North Center — 4040 N. Oakley Ave.
• Norwood Park — 5801 N. Natoma Ave.
• Portage Park — 4100 N. Long Ave.
• Abbott Park — 49 E. 95th St.
• Chatham Park — 8300 S. Cottage Grove Ave.
• Roseland — 10426 S. Michigan Ave.
• Garfield Ridge — 5674-B S. Archer Ave.
• Kelvyn Park — 2715 N. Cicero Ave.
• Auburn Gresham — 1040 W. 79th St.
• Englewood — 653-657 W. 63rd St.
• Austin — 5071 W. Congress Pkwy.
• Edgewater — 5917 N. Broadway Ave.
• South Chicago — 9233 S. Burley Ave.