A vast heat dome over the central United States is driving dangerous temperatures above 100 degrees Fahrenheit from Dallas to North Dakota, with roughly 70 million people under heat advisories, watches, or warnings, according to the National Weather Service on Sunday. The nearly stationary high-pressure system is trapping hot air and pushing temperatures 10 to 15 degrees above seasonal norms. High humidity is further elevating heat index values, while overnight lows are expected to stay unusually warm, preventing normal cooling and increasing cumulative heat stress across the Southwest, Gulf Coast, Midwest, Great Plains, and parts of the Northern Rockies and Pacific Northwest.

Prepared by Olivia Bennett and reviewed by editorial team.