On Thursday at 2:04 p.m. EDT an updated heat advisory was issued by the National Weather Service in effect until 8 p.m. EDT for Iosco, Gladwin and Arenac counties.

Temperatures on Thursday could stay in the upper 90s but the heat index will bring "feels-like" temperatures to 105 degrees.

The Lehigh Valley will be under a heat advisory from 10 a.m. until 9 p.m. Regions to the south, such as Bucks County and Philadelphia, will be under an extreme heat warning then. It will feel close to 105 in those areas, according to forecasters.

The heat dome won't dissipate soon. Dangerous heat is expected across parts of the Central and Southeast. through July, the weather service says. High temperatures will reach 100 degrees from Texas to western Tennessee almost every day for a week or two, AccuWeather said.

Thursday is a NEXT Weather Alert Day in Southeast Michigan because of dangerous heat that will affect the region for one day.