A dangerous and widespread heat wave is building across the United States, with triple-digit temperatures expected in the Southwest and Great Plains before spreading eastward. The heat dome, driven by a high-pressure system, is forecast to affect as much as two-thirds of the continental U.S., with temperatures 15 to 25 degrees Fahrenheit (8 to 14 degrees Celsius) above normal. The extreme heat is expected to persist for a week or more, posing significant health risks, particularly at night when temperatures remain elevated, preventing the body from recovering.
Immediate Action & Core Facts
1. Heat Dome Expansion
A large heat dome is expected to build over the interior West this weekend before spreading into the Upper Midwest and later parts of the East. The most intense heat is projected to focus from the northern Rockies into the Midwest, with temperatures threatening records from Nevada to Wisconsin. Forecasters warn of temperatures climbing well above 100 degrees in multiple locations, including Salt Lake City, Bismarck, North Dakota, and Billings, Montana.
2. Health Risks and Advisories
Forecasters are advising people to stay hydrated and find places to cool off, as the prolonged heat increases the risk of heat-related illnesses. The National Weather Service has issued extreme heat warnings in parts of the West and northern Plains, emphasizing that the heat does not stop at night, which is particularly dangerous for health.
Deeper Dive & Context
Regional Impact
The heat wave is expected to bring record-breaking temperatures to several cities. Salt Lake City is forecast to reach 106 degrees, Bismarck 108 degrees, and Billings 109 degrees—all significantly above average for this time of year. As the heat spreads eastward, humidity will make conditions feel even hotter across parts of the north-central U.S. Midwestern cities like Minneapolis, Chicago, Detroit, and Cleveland are projected to see multiple days in the 90s, with Minneapolis and Chicago enduring at least four straight days at or above 90 degrees.
Historical Context
The heat dome is expected to be more intense and prolonged than a previous heat wave earlier in July. The Northeast will also see a return of heat and humidity, though the episode is forecast to be shorter and less severe. The hottest stretch in the Northeast is expected from Tuesday through Thursday, with mid- to upper-90s possible along the Interstate 95 corridor.
Expert Insights
Josh Adam, a meteorologist with the National Weather Service in Bismarck, North Dakota, noted that the dramatic spike in temperatures is unusual for a state where summer temperatures typically hover in the 80s. The lack of overnight cooling is particularly concerning for public health, as it prevents the body from recovering from the day's heat.
Preparedness and Response
Authorities are urging residents to take precautions, including staying indoors during peak heat hours, drinking plenty of water, and seeking air-conditioned spaces. Cooling centers are being set up in affected areas to provide relief for vulnerable populations. The prolonged nature of the heat wave underscores the importance of sustained preparedness and public health measures to mitigate its impact.