Most of Ohio is under a heat advisory with temperatures that will feel 100-plus. Here's the difference between a heat advisory, heat watch and heat warning.

AirVenture patrons are being advised to stay extremely well hydrated when visiting Wittman Regional Airport Wednesday.

The National Weather Service office in Mobile, Alabama, issued a heat advisory in Escambia, Santa Rosa and Okaloosa counties between 10 a.m. and 7 p.m. Monday. Heat index values are forecast to reach as high as 109℉ in portions of south central and southwest Alabama, northwest Florida and southeast Mississippi.

NWS expects the heat value to go up to 110 degrees. The organization warns that hot temperatures, coupled with humidity, may cause heat illness. Precautionary measures provided by NWS include drinking plenty of water, staying out of the sun and staying in air-conditioned rooms.

The National Weather Service is using new heat alert terminology beginning this summer to improve public awareness and understanding of what the weather service says is the leading cause of weather-related deaths in the country,

The National Weather Service released a heat advisory at 10:42 p.m. on Monday in effect until Tuesday at 9 p.m. for Blount, Etowah, Calhoun, Cherokee, Jefferson, Shelby, St. Clair, Talladega, Chilton,

The National Weather Service already has issued extreme heat warnings, watches and advisories across a swath of the Midwest and South.

Heat index values could rise to 110-112 degrees, according to the National Weather Service. Higher rain chances later in the week could offer relief.