An unusually intense and prolonged heat dome has settled over the eastern half of the United States just as Americans prepare to celebrate Independence Day outdoors — producing what meteorologists and public health officials describe as one of the highest single-day heat illness risk environments the country has seen in years.
More than 230 million Americans are forecast to experience temperatures above 90°F through the July 4 holiday weekend, and more than 140 municipalities are expected to see record-high temperatures by Saturday. Over 165 million Americans are at risk of "major" or "extreme" heat-related health issues on July 4 itself, according to the National Weather Service's HeatRisk experimental forecast product.
