GEOFF BENNETT: Dangerously high temperatures are set to scorch much of the country this week, as a brutal and long-lasting heat wave bears down on the East Coast and Midwest.

Hundreds of cities could hit record highs by Friday, when more than 175 million Americans will face either major or extreme heat risk, according to the National Weather Service.

For more, we turn now to Jeff Berardelli, meteorologist and climate specialist at WFLA in Tampa Bay.

Jeff, welcome back to the program.

So the National Weather Service, as we said, described this as a prolonged and extremely dangerous heat today.

What should we know as we head into the holiday weekend?

JEFF BERARDELLI, Chief Meteorologist, WFLA-TV: It's going to get worse as we head towards Thursday, Friday, and also into Saturday.

We're going to see the potential for a couple of all-time record highs, or at least very close to those record highs.

Generally, the I-95 Corridor, that's going to be ground zero for the hottest weather.

We could see temperatures max out between 100 and 105.

But when you factor in the humidity, there are going to be feels-like temperatures around 110, some places a little bit higher than that, and, again, the worst Thursday, Friday, Saturday, and it starts to get a little better, little, slowly better as we head to Sunday.

GEOFF BENNETT: So give us a sense of the next few days.

Walk us through it.

JEFF BERARDELLI: Yes, the next couple of days, actual high temperatures, 95 to as much as 105 degrees.

When you factor in the humidity, it feels-like temperatures are going to be about 105 to 110 in some of the hottest cities.

And I think, along the I-95 Corridor, we will likely exceed 110 for that heat index.

So it is going to be oppressive.

GEOFF BENNETT: Yesterday, there was a heat index of 106 in Chicago, 113 in Milwaukee.

We have seen cities like Philly and New York City declare heat emergencies.

Put this in perspective for us.

How hot are these temperatures compared to average?

JEFF BERARDELLI: Right.

So, again, we could see one or two all-time records, but the heat dome or the heat wave is not necessarily unprecedented.

But I'd put it somewhere around the 95 to 100 percentile in terms of how strong it is.

So it's one of the stronger heat domes or heat waves that we have seen, because it's long-lasting, because of all the extra humidity, because of the intensity of it, and because it's affecting such a large part of the country.

Again, the worst of it is the next couple of days, with temperatures getting close to 105 in cities like D.C., maybe even Philadelphia, probably a little less than that in New York.

It's rare we get to numbers like that.

GEOFF BENNETT: What's the impact of El Nino on all of this?

JEFF BERARDELLI: Yes, so there's a lot of heat building in the Tropical Pacific, the Eastern Tropical Pacific.

In fact, we're on pace for a super El Nino.

In fact, we're at record pace already.

This is probably going to be the strongest El Nino we have ever seen.

And we're already seeing it link up with the atmosphere.

And so extra heat is being put into the atmosphere already.

It's early for this to be happening.

So El Nino not only injects extra heat, but it also kind of augments the steering patterns across Earth.

And so we end up oftentimes with events that are somewhat unprecedented, especially during strong El Nino years, and the heat domes tend to be that much more amplified.

It's almost like a weather system on steroids, if you will.

And so we're seeing these heat domes play out all over the world right now.

GEOFF BENNETT: The last 11 years are the hottest on record.

We know the ocean is getting warmer, the Earth's surface temperature is rising, Europe is experiencing unprecedented heat right now.

What's the impact of climate change on all of this?

JEFF BERARDELLI: You know, climate change underlies all this, right?

Air temperatures are about three degrees Fahrenheit warmer than they were just a little over 100 years ago.

So, if you picture it like a building, if your foundation of the building is let's say three feet higher, well, then your building's going to be three feet higher.

So climate change is making all heat domes, every heat wave more intense, longer lasting, and also larger in scope.

And what we're seeing is unprecedented-type heat.

In fact, the heat wave in Europe that played out over the past week or so, there was a study that was done by World Weather Attribution.

They found that the heat dome was likely about six degrees Fahrenheit hotter than it otherwise would have been just 50 years ago.

And 50 years ago, it would have been virtually impossible without climate change.

So that's the impact on the European heat wave.

There's going to be another one shaping up as we head into the weekend and next week.

For the Eastern U.S., again, not an unprecedented heat wave, but climate change is certainly making it hotter than it would have otherwise been.

GEOFF BENNETT: Jeff Berardelli, meteorologist and climate specialist at WFLA there in Tampa Bay, thanks again for being with us.

JEFF BERARDELLI: You're welcome.