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What is a heat dome? Find out why New Jersey and many other states are sweltering.
What is a heat dome? Find out why New Jersey and many other states are sweltering.

Many U.S. states, including New Jersey, have experienced scorching heat this week, and the heat will continue throughout the weekend as a massive “heat dome” stretches across much of the country.

If you haven’t studied meteorology and are wondering what a heat dome is, here’s the answer.

According to the National Oceanic and Atmospheric Administration, better known as NOAA, a heat dome occurs “when the atmosphere traps hot air like a lid or cap over a particular region.”

It’s essentially a large, permanent dome of high pressure that’s not uncommon during the summer months, especially in places like the southwestern United States, notes the Washington Post.

However, the heat dome responsible for this week’s hot weather is a bit different, producing extreme triple-digit temperatures in some parts of the United States and affecting a broad swath of the eastern half of the country, from the Great Plains states through Maine in the northeast down to the Mid-Atlantic region.

Meteorologists predict that the heat index – the perceived heat combined with high temperatures and high humidity – will be above 95 degrees in most parts of New Jersey on Friday and above 100 degrees on Saturday and Sunday.

Is a heat dome a heat wave?

Experts say it’s helpful to think of a heat dome as what’s happening in the atmosphere. A heat wave is how the high temperatures affect people on the ground, says Ken Kunkel, a research professor of atmospheric sciences at North Carolina State University.

When a high pressure area forms in the upper atmosphere, the air below sinks and is compressed, causing temperatures in the lower atmosphere to rise.

As hot air expands, a curved dome is created.

The boundaries of this week’s heat dome are not clearly defined, Kunkel said, but the National Weather Service has announced that the most extreme heat is expected in the Ohio Valley and the Northeast.

The eastern heat dome follows a heat dome that occurred earlier than usual in the Southwest this month.

Construction workers battle temperatures of 93 degrees as they pave the driveway of a store along Route 18 South in East Brunswick on Thursday, June 20, 2024. The intense heat wave is expected to continue through the weekend, with even higher temperatures expected.

What is a heat wave?

A heat wave is defined by the intensity of the heat, its duration and its location, said Jeff Masters, a meteorologist at Yale Climate Connections.

In general, several days of temperatures above 90 degrees in Texas are “no big deal,” Masters said. But further north, temperatures between 95 and 100 degrees were forecast for the Midwest and Northeast this week and weekend, with the heat index — the perceived heat after taking humidity into account — expected to be between 95 and 100 degrees and even higher in some areas.

“The population is simply not used to this kind of heat,” Masters said.

The National Weather Service said some areas are likely to meet or surpass daily records, with the intense heat wave lasting through the weekend in some areas, including New Jersey. In the Garden State, a heat wave is considered three or more consecutive days of temperatures of 90 degrees or higher.

The combination of clear skies and higher sun altitude in summer can lead to high heat index readings. Humidity makes the weather feel hotter as the body cools itself through sweating and has to work harder in already humid air.

Meteorologists predict that some record-breaking temperatures could be reached or exceeded on Sunday, June 23, as New Jersey’s first heat wave of 2024 continues.

Will records be set in New Jersey?

Although the temperature rose to 97 degrees at Newark Liberty International Airport on Thursday, the first official day of summer, it was not hot enough to match or beat the daily record of 98 degrees set on June 20, 2012.

With the heat wave intensifying this weekend, New Jersey has a chance of breaking some records, according to the latest temperature forecasts from the National Weather Service.

We probably set the record in Newark on Friday when temperatures reached 100 degrees. As the weekend approaches, Sunday is shaping up to be the best opportunity to reach or break record highs at each of the Weather Service’s three main stations in the Garden State – Newark, Trenton and Atlantic City.

This is no easy task, however. The current record temperatures for June 23 are 97 degrees in Newark and Trenton and 98 degrees in Atlantic City.

Current weather radar

The Associated Press contributed to this report.

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Len Melisurgo can be reached at [email protected] or on X at @LensReality.

By Seren