Millions of sultry domes suffocate in the eastern United States
In the following week
Heatrisk is forecast on July 27, 2025. NWSHeatrisk is an experimental color digital index that can occur within 24 hours of predicted risks of thermally-related effects.
National Meteorological Administration/NOAA
Meteorologists warn that millions of people will be stuffy next week under the heat dome that rotates in the eastern half of the United States.
On July 23, more than 35 million people were at risk of high or extreme heat impact, according to the National Weather Service, a branch of the National Oceanic and Atmospheric Administration. This high-risk population is currently centered on the Mississippi River Valley. Current forecasts show that the figure doubled on July 24 as hot weather moves eastward. By July 25, it will reach nearly 90 million, with consultations or warnings covering much of the country.
“Even in midsummer, it's worth noting,” said Bryan Jackson, a meteorologist at the NWS Weather Forecast Center in University Park, Maryland.
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The tragic condition is the result of what meteorologists call the thermal dome, a weather pattern that occurs when high-pressure mass traps are heated. This phenomenon is often caused by the behavior of high-altitude rivers called jets.
For people under the influence of the sultry heat of the hot dome, the weather patterns can be boring and tolerated. “Hot domes usually form slowly and emit slowly,” Jackson said.
The current event fits the pattern, expected to last at least a full week of caloric conditions. However, a simple glance at the thermometer may not show unpleasant conditions. This heat wave is especially affected by high humidity, which makes the overnight temperature relatively warm, which leaves people with little breath.
“Since it's midsummer, and the temperature isn't that much,” Jackson said. “But with the high moisture we're seeing, there will actually be a lot of record-breaking lowest temperatures.”
Jackson said the Hot Dome is currently centered around Memphis, Tennessee, and the Southeast will see tough temperatures throughout the week. However, as the hot air rotates, the full geographical range of the hot dome will move. Today, the Midwest is stuffy, as it has been for a few days, and is a bit worsened by an unpleasant phenomenon known as “corn sweat”.
The Ohio Valley will face its worst conditions on July 24, with the eastern coastal areas doing so on July 25. Meanwhile, the Southeast U.S. is expected to see the highest heat risk over the weekend and next week. Jackson noted that during this period, the mid-Atlantic, Carolina, and Southeast are likely to break records of the highest overnight lows.
As climate change continues to develop, the long-term heat of summer has become more common. A recent analysis shows that many cities in the eastern U.S. are experiencing increasing “hot stripes”, which are three or more days in a row, with the highest temperatures in the top 10% of local daily altitudes from 1991 to 2020.
If you live in an affected area, check out our scientifically supported tips to keep your home healthy and keep your home cool in extremely high heat.