Epic heat wave to expand from Midwest to East Coast, bringing warnings to 72 million

View of a Saguaro, a resilient desert cacti affected by Arizona's extreme heat and prolonged drought, in Phoenix, Arizona, U.S., July 25, 2023. Staff | Reuters

Almost 72 million people across the country were under warnings of extreme heat Monday morning, the National Weather Service said.

With Thursday's seasonal solstice taking place amid a weeklong heat wave expected for the East Coast and the Midwest, the summer of 2024 is coming in hot.

Extreme heat warnings were in place for Chicago, St. Louis, Indianapolis, Detroit, Cleveland, Cincinnati, Pittsburgh, Philadelphia, Boston, New York City and Albany, New York.

Models show the heat could last through Friday and beyond.

"The duration of this heat wave is notable and potentially the longest experienced in decades for some locations," the federal Weather Prediction Center said.

A high pressure system called an upper-level ridge that is over the Ohio Valley is expanding over the Midwest and the East Coast and will produce clear skies, warm, stable air and record-breaking temperatures in the 90s and beyond, forecasters say.

Some areas will experience temperatures as high as 105 degrees Fahrenheit, according to the weather service. Forecasters say temperatures will reach as high as 25 degrees above normal for many areas under the summer system.

The weather service office in Phoenix said it reached 112 degrees there Sunday, 7 degrees above average and not far short of the daily record of 115.

The Nevada Division of Emergency Management warned people not to rely on fans to stay cool and to seek air-conditioned places such as libraries and shopping malls, or the cooling centers that have been opened across the Southwest in recent weeks.

New temperature records could be set from the Ohio Valley and the lower Great Lakes into the northern mid-Atlantic and the Northeast, the weather service said.

The weather service office for Pittsburgh said it "could be the most impactful heat wave of the 21st century."

Buffalo Public Schools said in a statement it was implementing half days for four of the week's five days. The schedule will allow pre-K through 8th grade students go home by the end of the lunch hour.

Nights are likely to provide a minor dousing of relief, with low temperatures across that quarter of the nation to dip into the upper 60s and the 70s, forecasters said.

On the northwest side of the heat, flash flooding could take place in the Dakotas and Minnesota on Monday, forecasters said. On the southwest side, rain pushing in from the Gulf of Mexico was expected in parts of Texas and Louisiana, possibly through Wednesday, they said.

The weather service is also on the lookout for any possible tropical storms developing in the Gulf, it said.