‘Heat Dome’ Descends on Central United States

Forecasts suggest more than 30 million people could see temperatures topping 100 degrees this week

heat map of U.S>
A map from NOAA showing parts of the country that are under heat advisory as of July 27 (orange), excessive heat watch (brown) and excessive heat warning (fuchsia). The shaded areas of the map with heat related advisories or warnings encompass more than 30 million people. NOAA / NWS

In what is becoming a familiar refrain this summer, a heat wave is settling over the central United States, report Matthew Cappucci and Jason Samenow for the Washington Post. More than 30 million Americans will fall under some kind of heat-related advisory during the so-called heat dome.

The National Oceanic and Atmospheric Administration (NOAA) explains a heat dome as a scenario when a mass of hot air gets trapped under an atmospheric layer of high-pressure, trapping the sweltering heat like a domed pot lid.

This particular heat dome will bring temperatures that are five to ten degrees Fahrenheit above average to locales ranging from Georgia in the southeast all the way to parts of Montana, according to the Post. A statement from NOAA predicts temperatures above 100 degrees in the Dakotas and Montana and heat of up to 110 degrees in Missouri, Arkansas and Oklahoma.

The heat dome is also expected to deliver thunderstorms and lightning to its northern periphery near the Great Lakes, while at the same time exacerbating the drought that is throttling rainfall in the western U.S., reports Oliver Milman for the Guardian.

This latest heat wave comes on the heels of a heatwave that killed hundreds of people and cooked billions of sea creatures alive in the Pacific Northwest in late June.

“It’s been a severe and dangerous summer, some of the heatwaves have been devastatingly hot,” Michael Wehner, a climate scientist at the Lawrence Berkeley National Laboratory, tells the Guardian. “We certainly expected these type of temperatures as global warming continues but I don’t think anyone anticipated they would be so hot right now. I don’t think we could’ve expected so many heatwaves in the same general region in one summer.”

Recently published research suggests that climate change is going to make “record shattering” heatwaves—like the one that sent the mercury thermometers climbing all the way to 121 degrees in Canada’s British Columbia—much more common, reports Damian Carrington for the Guardian. Research has already shown that heat waves and other forms of extreme weather are expected to become more common under climate change, but the new study focused only on the most blood-boiling heatwaves that would demolish local temperature records by roughly nine degrees.

The study’s computer models predict that without dramatic action to reduce greenhouse gas emissions, these record-breaking heat waves will become two to seven times more likely to occur in the next three decades and three to 21 times more likely from 2051 to 2080, according to the Guardian.

Researchers say these findings and this summer’s extreme heat are warnings that local and national governments need to prepare for these kinds of weather events to prevent deaths from heat stress even in places that typically don’t get that hot.

“These sort of events are completely unprecedented, you expect records to be beaten by tenths of a degree, not 5F or more. It’s a teachable moment in many ways for the public that climate change is here and now and dangerous,” Wehner tells the Guardian. “It isn’t our grandchildren’s problem, it’s our problem.”