An excessive heat warning, the highest alert level on a four-tier scale, means everyone needs to take precautions to stay safe in the heat because "you may become seriously ill or even die," the National Weather Service says.

A heat advisory is issued by the National Weather Service when a heat index of 105 degrees or higher is expected for at least two hours in Miami-Dade. An advisory is issued for Broward when a heat index of 107 degrees is expected for at least two hours.

In Palm Beach County, while the heat index has been overwhelming, the daytime highs have been near normal for mid-July, hovering around 90 degrees.

On Thursday at 1:22 p.m. a heat advisory was issued by the National Weather Service valid from Saturday 11 a.m. until Monday 11 p.m. for Harney County.

It's another very hot day across the area with temperatures topping out in the 90s for most locations. Heat index values through the afternoon will reach between 100 and 105 degrees for most areas, with portions of the Eastern Shore possibly reaching close to 110 degrees.