Story highlights Temperatures close to 100 degrees are expected across dozens of states

Five elderly Michigan residents died due to record heat and humidity

(CNN) Six heat-related deaths have been reported as dangerously high temperatures continue to scorch portions of the Eastern U.S., where heat advisories remain in effect Monday, according to the National Weather Service.

Cody Flom, 12, suffered a fatal heat stroke while hiking Friday at the Sonoran Mountain Preserve in Arizona, where temperatures soared to a sweltering 111 degrees, a Phoenix Fire Dept. spokesperson said.

Heat indexes well over 100 degrees are expected across dozens of states in the nation's central and eastern portions, the National Weather Service forecasts. A heat index, or the "feels like" temperature, combines the effects of temperature and humidity on the human body.

Temperatures also could reach the century mark Monday afternoon in New York and Washington, and it's going to be hot in Philadelphia this week for the Democratic National Convention. The mercury will hit the middle to upper 90s through the middle of the week but high humidity will make it feel like it's in the triple digits.

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