CHICAGO (AP) — The National Weather Service says high temperatures in the middle to possibly upper 90s Saturday through Monday will lead to potentially hazardous conditions in Chicago, especially for elderly people and those with pre-existing health conditions.

It says peak afternoon heat indices of 100 to 105 are forecast for the three days. Nighttime lows in the city will likely only fall to around 80.

The weather service says the extended duration of heat, combined with nearly full sunshine and "oppressive" warmth even at night can lead to dehydration, heat exhaustion or heat stroke.

Residents of Chicago can call 311 to request well-being checks for elderly friends or relatives and to help find a cooling center.