Dangerous heat dome will scorch the East Coast, NWS warns

The National Weather Service issued a Heat Advisory for coastal southeast Connecticut and eastern Long Island as dangerous heat and humidity remained entrenched over the East Coast, with heat-index forecasts extending across days 3 through 7. Older adults, outdoor workers, people without air conditioning and patients vulnerable to heat stress faced the highest risk as the spell threatened to push hospital demand and electricity use higher at the same time.

The hot air mass is being reinforced by a strong upper-level high-pressure ridge expanding eastward toward the East Coast, a pattern that can lock in oppressive heat for several days and keep nights from cooling enough for recovery.

More than 60 percent of Americans were expected to experience extreme heat and humidity in the days ahead, and more than 125 million people were under dangerous heat coast to coast. In the Philadelphia area, Extreme Heat Warnings and Heat Advisories were in effect as the ridge pushed eastward. Heat indices could reach or exceed 100 degrees in multiple East Coast cities.

The National Weather Service counts extreme heat as the weather phenomenon that has killed more people on average over the last 10 years than any other. Nights stay too warm for the body to cool down, especially hard on workers who labor outdoors and on families without reliable air conditioning.

NOAA estimates that about one-third of the U.S. economy, roughly $3 trillion, is sensitive to weather and climate, which means prolonged heat can ripple through power demand, work schedules and local business activity just as quickly as it strains public health systems.