From Polk County Emergency Management:
The National Weather Service has issued a Heat Advisory, which will include Polk County, from noon on Wednesday, 7/19 until 8 pm Saturday, 7/22. Temperatures each day will rise rapidly after sunrise to reach heat index values between 100 and 110 degrees by early afternoon. The heat will persist into the early morning hours, with very little overnight relief. Both the extreme temperatures and the duration of this event will put people at significant risk of heat-related illness or death.
UPDATE
To give residents of Polk County an additional option to reduce their risk for serious heat-related health issues, an extended hour cooling center will be open tonight Wednesday, July 19, 2017 and tomorrow Thursday, July 20, 2017 from 5:00 p.m. to 11:00 p.m. at Zion Lutheran Church at 4300 Beaver Ave.