* WHAT...Dangerously hot conditions with heat index values exceeding 100 degrees multiple days.
* WHERE...Grundy, Butler, Cerro Gordo, Franklin, Hancock, Winnebago, Worth, Black Hawk, and Bremer Counties.
* WHEN...From Sunday afternoon through Tuesday evening.
* IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events.
* ADDITIONAL DETAILS...Excessive heat will persist through much of next week, potentially including the 4th of July weekend.