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Extreme Heat Warnings Impact 40 Million Across Central and Southern U.S.
At least 40 million residents in central and southern regions of the United States faced extreme heat warnings on Sunday as a persistent heat wave, combined with high humidity, continued for a second consecutive day.
Heat indexes soared above 105 degrees Fahrenheit (40.5 Celsius) in areas stretching from Minnesota to Mississippi, and extended westward into southern California and Nevada. Some parts of the Southwest were forecast to reach blistering highs of up to 120 degrees Fahrenheit (49 Celsius), according to the National Weather Service.
Meteorologists attributed the intense heat to a “heat dome” – a weather pattern where atmospheric conditions trap heat close to the ground, intensifying and prolonging already hot temperatures.
Saturday saw Rapid City, South Dakota, shatter its all-time temperature record with 112 degrees Fahrenheit (44 Celsius). The extreme heat also led to the cancellation of a horse race at Canterbury Park in Shakopee, Minnesota, on Sunday.
Bob Oravec, a meteorologist with the National Weather Service, noted, “Right now, it’s affecting a lot of people right in the middle of the country. The core of the heat sinks southward by early next week.”
The combination of moist air and the heat dome has also generated volatile weather conditions near the Great Lakes, including risks of severe thunderstorms, flash flooding, and hail. These heavy storms are expected to move eastward in the coming days.
Oravec added, “If you have a heat dome in one part of the country, you’ll have a different corresponding weather in another part. It’s all related.”
While some temporary relief is anticipated for the central U.S. by midweek, high temperatures may return by the weekend.
Authorities emphasized that vulnerable groups-such as children, older adults, and individuals with certain medical conditions-are at increased risk for heat-related illnesses like heat stroke. Officials urge people to seek air-conditioned environments or cooling centers, stay hydrated, and avoid prolonged exposure to direct sunlight.
This heat wave comes amid a record-setting year, as the continental U.S. experienced its second-hottest first half of the year on record, according to data from the National Centers for Environmental Information.