The heat wave comes on the heels of another record-breaking heat wave last week, which hit many of the same regions that were poised to be hit by the second wave.
From Lincoln, Nebraska, to Fargo, North Dakota, temperatures will hit triple digits by the end of the weekend. The heat wave targeting the Northern Plains will be 20 to 25 degrees above normal.
There will be a respite from the heat, albeit short-lived, for areas of the Great Lakes and the Mid-Atlantic, where thousands are still without power from the storms earlier this week.
Temperatures will be 10 to 25 degrees below normal Saturday from Chicago to Portland, Maine. But as soon as temperatures have dropped, they will recover early next week.
In all, more than 240 million people, about 75% of the Lower 48, will see temperatures of 90 degrees or more in the next seven days.
Another big heat wave next week
The heat dome currently over the Northern Plains will move east to the Midwest and South, creating another record week and shortening the heat spell that many of these states will face in the coming days.
St. Louis is forecast to have a high temperature of 84 degrees Saturday. By the time Tuesday arrives, the maximum temperature will rise to 100 degrees.
Chicago’s high temperature on Saturday may not even reach 70 degrees, but by Monday the temperature will skyrocket to 95 degrees.
Raleigh, North Carolina, is moving from a high of 83 degrees on Sunday to a forecast high of 100 by Wednesday.
Heat is the leading cause of weather-related deaths in the United States, and providing advice on the likelihood of heat-related illness — including cramps, exhaustion, stroke and possible death — helps protect the public in extreme heat.
However, sometimes the low temperatures at night are just as responsible as the high temperatures during the day.
“Your body needs to cool down at night and actually expects it while you sleep,” says Jenn Varian, a meteorologist with the National Weather Service’s office in Las Vegas. “If we have really hot temperatures at night, your body just can’t cool down properly, which in itself can cause complications, but you’re also less prepared for the heat during the day.”
Temperatures need to drop to a minimum of 80 degrees to recover. In fact, a person can lose up to two liters of fluid through sweating overnight if the temperature never drops below 85 degrees.
Dozens of cities could break records for the hottest low morning temperatures in the next five days. More records are expected next week in the Midwest, Southeast and Mid-Atlantic.
