Heat dome to push extreme temperatures across much of US this week

A bulge in the jet stream is conspiring with a large high-pressure system to create a “heat dome,” bringing temperatures approaching triple digits that could linger into August across a swath of the Midwest and East, forecasters say.

Dallas could see 100 degrees for the first time in 2025. The Kansas City, Missouri, area, which hasn’t seen 100 degrees in two years, could reach the figure multiple times this week, AccuWeather Senior Meteorologist Chad Merrill said.

The National Weather Service, which is predicting a heat index of 107 on July 21 and 106 on July 22 for Kansas City, has issued an extreme heat warning there until the late on July 24.

Almost 85 million Americans from South Dakota to Texas and North Carolina to Florida were already under National Weather Service extreme heat warnings, watches or advisories July 21. The heat will intensify July 22 and deep into the week − and possibly beyond.

“By midweek, 90s will have spread from the South into the Midwest and Great Lakes,” wrote Jonathan Erdman, a senior meteorologist at weather.com.

Parts of Texas, Arkansas and Louisiana will have highs peak at near or above 100 degrees, and a much larger area of the South, Midwest and Great Lakes will see a heat index surpassing 100 degrees, he said.

“This has the look of a long-lasting heat wave with limited rainfall,” Merrill said. “Drought will expand through the central Plains by mid-August and worsen in Kansas and Nebraska, where there are already pockets of moderate to extreme drought.”

Developments:

∎ Thunderstorms forecast for July 21 could trigger flash floods in parts of the Northwest, Southwest, Midwest, Mid-South and Southeast.

∎ Chicago corn, wheat and soybean futures fell July 21 as traders weighed concerns that hot weather will shrink U.S. yields, Reuters reported.

∎ Areas from the central and northern Plains to the Ohio Valley and Southeast could face complexes of damaging wind and rain storms known as derechos, AccuWeather said.

Angry storms, ‘heat dome’: Threaten to fuel dangerous weather week

How long will the heat dome last?

Erdman wrote that the heat wave may last until at least the last weekend of July in the Plains and South, while slowly expanding west toward the Rockies.

“Our longer range outlooks suggest the Northeast has the best chance of eventually seeing some heat relief around that last weekend of July,” Erdman said.

Hot cars a danger for kids

The hot weather increases the risk of children being left in cars that heat up in the sun. The advocacy group Kids and Cars Safety says 15 deaths of young children left in hot cars already have been reported across the nation this year. Last year 41 such deaths were recorded.

Transportation Secretary Sean Duffy said recently that, as a father to nine, he understands how difficult it can be to keep track of kids every minute.

“But there is no excuse for leaving a child in a parked vehicle,” he said. “Every parent, sibling, relative and babysitter needs to understand the severity of doing so. It’s the only way we can prevent more of these heartbreaking losses of life.”

What is a heat dome?

Heat dome is not actually a scientific term, according to climatecheck.com, which says the term does effectively describe the “oppressive” high-pressure atmospheric systems that cause warm air to be pushed to the Earth’s surface and trapped there for long periods of time.

“The dome traps high-pressure air in one place, like the lid on a pot,” the website says. “These large zones of hot air result in a combination of blistering temperatures, devastating wildfires, and drought conditions.”

Brief respite for Northeast before heat dome advances

The Northeast will enjoy a few days of lower humidity and cooler temperatures before a “bubble” from the heat dome slips away from the Midwest and brings brutal heat east, AccuWeather forecasts. Temperatures will dip into the 60s in New York and Washington, D.C., the 50s in Boston and into the 40s in some areas of the Northeast’s interior.

The respite will wrap up by July 25, when the high temperature for Washington is forecast to reach almost 100 degrees. Detroit will reach deep into the 90s Thursday and Friday. Philadelphia will push close to 100 on July 25 and July 26.

“The late-week scorcher heading into the East will be a quick whiplash,” Merrill said.

This article originally appeared on USA TODAY: Heat dome to push extreme temperatures across much of US