Heat Wave Enters 7th Day, but the End Is in Sight

The end of the unusually early heat wave that gripped much of the United States over the past seven days is in sight.

But first, the country will need to endure another day, possibly two, of scorching hot temperatures in the Mid-Atlantic States and along the I-95 urban corridor on the East Coast.

The National Weather Service predicts that the heat wave, which has more than 100 million people under heat advisory alerts, will last through early this upcoming week.

The Mid-Atlantic States and cities along the I-95 urban corridor, from Washington, D.C., to New York, will continue to simmer through Sunday. Heat advisories have been issued for areas east of the Blue Ridge Mountains, where the heat index — a measure of how the heat feels with humidity taken into account — is forecast to range between 100 and 108 degrees.

Already, several decades-old temperature records were broken on Saturday afternoon. Baltimore reached 101 degrees, breaking the daily high temperature record of 100 degrees, set in 1988. And in Dulles, Va., the temperature reached 100 degrees, breaking the previous record of 99 degrees, also set in 1988.

Forecasters say there will be some relief in other parts of the country that were hit hard last week. In New England, record-breaking temperatures have already receded, and forecasters predict that Sunday will bring lower temperatures to the Ohio Valley and the Midwest. This is good news for a region that forecasters described as particularly susceptible to heat-related illnesses, given how anomalous the temperatures were for this time of year.

In Detroit, the heat index is forecast to fall from a high of 95 degrees on Saturday to 87 degrees on Sunday. And in Chicago, the heat index is expected to decline from a Saturday high of 96 degrees to 79 degrees.

The National Weather Service warned that the heat wave could be the longest experienced in decades for some locations. In recent years, global warming has made heat waves hotter, more frequent and longer lasting.

Extended heat waves come with added dangers, as the stress the heat puts on the body is compounded the longer high temperatures last.

The health consequences of this heat wave are starting to show up in the data. Heat-related emergency room visits spiked in regions of the United States that were hit hardest by the heat wave last week, according to a tracker by the Centers for Disease Control and Prevention. In New England, the number of heat-related visits climbed to 833 per 100,000 last Thursday — the highest rate in the country all week.