Today is the summer solstice, and much of the country is going to be baking in serious heat starting this weekend.

A heat dome is expected to keep temperatures soaring above 90 degrees in many states. More than 200 million people will feel those effects, and tens of millions more are going to be grappling with triple-digit heat.

Our Stephanie Sy has our look at what you need to know about the days ahead.

Jeff, here in Phoenix, where the high reached 117 degrees yesterday,

triple-digit heat at this time of year is not unusual.

But places like Omaha, Albuquerque, and Denver are experiencing temperatures over 100 degrees today.

Looking at the forecasts on these maps, you can see how tomorrow in particular, many parts

of the central plains and upper Midwest are in that darker color, meaning dangerous heat.

That's expected to spread to the east coast in coming days.

Matthew Capucci is a meteorologist with myradar.com, and he joins me now.

Matthew, thanks so much for joining the program.

So what should we know about this heat wave?

Which parts of the country are going to be hit the hardest?

How long will it last?

Yeah, it's a very expansive long- long duration heat event. In fact, 220 million

Americans will see temperatures over 90. About 35 million Americans seeing triple digit heat. And we're

not just talking to desert southwest. We're talking the eastern seaboard as well. The heat dome

really starts to get established this weekend, Saturday into especially Sunday over parts of the

Corn Belt to the Midwest, and then really is spreading all the way to the East Coast, lasting until,

I'd say, Wednesday or Thursday before we finally start to see some relief. Now, we talked about the heat

in Arizona moments ago. Temperatures nearing 115 degrees. It's going to be a very long duration,

significant heat events.

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