A seven-day “Heatrisk” card from the national heat health system is a large part of the east of the United States under the influence of a heat of heat causing an extremely high temperature.
ESRI, TomTom, Garmin, FAO, NOAA, USGS, EPA, USFWS / screenshot by NPR
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ESRI, TomTom, Garmin, FAO, NOAA, USGS, EPA, USFWS / screenshot by NPR
A heat dome brings oppressive warmth to the eastern half of the contiguous United States, with forecastists warning people in these areas to take precautions to deal with high extreme temperatures. The phenomenon occurs when high pressure linger and traps hot air near the surface, while also removing clouds and precipitation.
Warnings and heat reviews “extend from the lower Mississippi and Midwest valley to the East Coast, affecting nearly 160 million people”, the National Weather Service said Tuesday morning.
Boston, mass., hit 100 degrees Early Tuesday afternoon. Temperatures have climbed beyond 95 degrees in many parts of Pennsylvania, with heat index values above 100 degrees Expected in cities like Philadelphia, Lancaster and Pittsburgh. In the center of North Carolina, the forecasters were waiting The values of the heat index up to 115 degrees.
What is a heat dome?
“It acts almost as a cover on a pot,” said Alex Lamers of the National Weather Service at NPR, discussing the operation of a heat dome. Lamers are the head of the operations branch at the Weather Prediction Center.
“If you’ve done grilled cheese in a saucepan and put a lid there, it melts the cheese faster because the lid helps trap the heat,” said Lamers. “It is a similar concept here: you get a large high pressure system in the upper parts of the atmosphere and this allows this heat to build below for several days.”
It’s true: days, even weeks.
A heat dome is essentially a massive area of high pressure and hot air which “is distributed” in a region. The exact location is generally linked to the Jet Stream – and at the moment, the Jet Stream suddenly moves northeastFrom the Baja Upper Peninsula to California to a place just west of Lake Michigan. This allows a heat of heat to persist in a large part of the eastern half of the United States
When a heat dome is on a large area, it can form a sort of feedback loop, said lamers, adding that high pressure generally means dry time, which can help drive even higher heat.
The extreme heat has broken records in many regions of the United States in recent years, and scientists warn that we will probably see even more dangerous temperatures in the future – a trend linked to Climate change caused by humans. 2023 and 2024 were appointed on The hottest years ever recorded.
With temperatures that hovered nearly 100 degrees, a woman protects herself from the sun while walking in Boston Common on Tuesday.
Charles Krupa / AP
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Charles Krupa / AP
Health alerts again mark the start of summer
People living in the Midwest and the Northeast can be forgiven to have a feeling of weather weather: almost exactly a year ago, a heat dome brought record high temperatures In these areas, sending summer to a scorching start.
The current extreme heat fight should persist in the Midwest throughout this week, bringing temperatures much superior to the average. But a cold front should bring relief to the northeast and in the middle of the Atlantic later this week, said the NWS.
While record summits will make the headlines, low -warmed night temperatures will make people refresh and recover when they will finally get a break from the sun.
Experts warn that the oppressive heat could present a particular risk for children and people with existing health problems – but the meteorological service warns: “This level of heat can be dangerous for anyone without cooling and / or adequate hydration.”
Whoever must be outside should consider the advice of Dr Jess Weisz, pediatrician at the National Children’s Hospital in Washington, DC, DC, said Morning edition These tips: “Take a lot of breaks, especially if they are physically active, drinking a lot of water, also using sun protection” as a sunscreen and a hat.
Heat domes affect different parts of us
Heat domes have struck other regions in recent years. In At the beginning of June of last yearThe west of the United States has undergone high temperatures 20 to 30 degrees warmer than normal. In 2023, a dome that formed on a huge band of large plains, the south and the midwest at the end of August brought a wave of record temperatures from New Orleans to Chicago. For the second consecutive year, there was more than 600 heat -related deaths In the county of Maricopa in Arizona in 2024 and Phoenix saw a record 113 consecutive days temperatures or greater than 100 degrees.
And in 2021, a heat dome toasted Oregon, Washington and other parts of the northwest at the start of the summercausing hundreds of deaths.
Last month, almost all parts of the world were affected by generalized warming.
“May 2025 was the hottest May second ever recorded,” according to the national integrated thermal health information system. “Temperatures … were much warmer than the average in the parts of each continent.”
