CHICAGO (CBS) — The hottest temperatures of the year are on the way for Chicago over the next three days, prompting an excessive heat warning from Thursday afternoon through Saturday night.

While Thursday is starting off with rain showers, and a marginal risk of severe storms, skies are expected to clear by midday, and intense heat will move in, with temperatures reaching the mid 90s Thursday afternoon.

Friday and Saturday will bring the hottest conditions as temperatures will climb to nearly 100. Coupled with high humidity, heat index values are expected to be well over 100 both days, possibly reaching as high as 114.

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The National Weather Service has issued an excessive heat warning for virtually all of Illinois and Indiana, starting at noon Thursday and continuing through 7 p.m. on Saturday.

Nighttime hours won’t bring much relief from the heat the next few days, with temperatures dropping only to around 80 on Thursday and Friday night.