Dangerous heat that has scorched the Southwest for days is now spreading into the nation's midsection, with the Plains and Midwest bracing for significantly higher temperatures and humidity. By Sunday, heat indices in places like Kansas City, Missouri, and Des Moines, Iowa, are expected to make it feel like 100 degrees Fahrenheit. This pattern is projected to continue into the first week of September.
By Tuesday, the Chicago metropolitan area could experience heat index values exceeding 100 degrees Fahrenheit, with similar conditions expected in Charlotte and Raleigh, North Carolina, Richmond, Virginia, and Washington, D.C. Nighttime temperatures across parts of the southern Plains and the Mid-Atlantic are expected to offer little relief, with lows remaining in the 70s for multiple consecutive days.
While the Northeast is expected to largely miss this intense heat wave, some areas in the Upper Midwest and extending to the Northeast may experience wet and stormy weather. These conditions could bring isolated incidents of flash flooding and severe storms over the course of the week.
Meanwhile, the Western United States is dealing with the aftermath of severe thunderstorms that produced flash flooding. On Saturday, Grand Canyon National Park in Arizona experienced significant flooding. By Sunday morning, 62 people were evacuated by air from the Phantom Ranch area at the bottom of the Grand Canyon. No injuries were immediately reported.
Evacuations were ongoing Sunday afternoon in the Grand Canyon, with park officials seeking information on more than 20 individuals who may be unaccounted for following the flooding event. In Utah, flooding of Cottonwood Creek in Emery County prompted evacuations of several homes and apartments.
Additional flash flooding is possible in parts of the West on Sunday afternoon as monsoonal moisture fuels scattered thunderstorms. Flood watches were in effect Sunday across portions of Arizona, Utah, and Colorado, including the cities of Tucson, Phoenix, Flagstaff, Cedar City, and Grand Junction. These storms could also produce strong wind gusts, frequent lightning, and blowing dust.