Jacksonville under a heat advisory

JACKSONVILLE, Fla. – Jacksonville and all of our local counties north into Georgia were put under a heat advisory.

The extreme temperatures are what's triggering that Weather Authority Alert Day Warning. It could be the hottest day the River City has seen in six years!  This could set off some severe storms later tonight. Our Weather Authority Alert Day starts at noon and runs until midnight. We can expect scorching temperatures and some powerful thunderstorms.

Roughly 66 million Americans will be under some form of hot weather advisory into next week.

That's about a fifth of the entire U.S. population.

When that Weather Authority Alert Day begins at noon, News4Jax will have hourly updates on Channel 4 to track the temperatures and the storms. You can also get instant information on The Weather Authority app and more information here: http://www.news4jax.com/weather/dangerous-heat-expands-into-jacksonville