Over 140 million Americans will be under the highest-level extreme heat alerts by Sunday during a wave of above-average temperatures.

"A dangerous, widespread heat wave will bake the central and eastern U.S., bringing the hottest temperatures of the year and uncomfortably muggy air to the Midwest and Northeast that in some areas could last into much of next week,

After topping 90 degrees June 21 for the first time this year, temperatures in Indianapolis will continue to climb for the next two days.