Residents across a wide swath of the Northeast and Midwest braced Sunday for more screaming heat as officials issued dire warnings, hawked ice cream – and even urged criminals to stay home and binge-watch Netflix.
Temperatures at or near 100 degrees were forecast for Washington, Baltimore, Philadelphia, New York City, Boston and hundreds of cities and towns in between. Tack on the humidity, and it will feel like 110 in some places.
Since it did not cool down much Saturday night, the temperatures rose quickly, AccuWeather warned.
"With temperatures starting the day near levels that are closer to the day's average high, Sunday could be the hottest day of this heat wave all along the Interstate 95 corridor," AccuWeather senior meteorologist Kristina Pydynowski said.
Boston Mayor Martin Walsh declared a heat emergency and opened community centers. He warned residents not to leave children or pets alone in vehicles "even for short periods of time."
The National Weather Service extended "excessive heat" warnings across much of the East. St. Louis got one, too, as did Cincinnati. Both joined Oklahoma City in facing heat index values Sunday in excess of 100 degrees.
St. Louis Mayor Lyda Krewson tweeted a plug for ice creameries, noting that Sunday is National Ice Cream Day.
"Cool off today at one of the many great STL ice cream spots – @ClementinesSTL, @CrownCandy, @Fountain_Locust, Ices Plain and Fancy, Jeni’s, Tower Grove Creamery, and of course we can’t forget frozen custard at @RealTedDrewes," Krewson tweeted.
Ice cream shops might move plenty of product. More than 200 million Americans were sweating in temperatures well beyond the norm even for the dead of summer.
There were concerns that the heat would drive up energy demand and possibly trigger outages. New York Mayor Bill de Blasio ordered big buildings to set thermostats no lower than 78 degrees through Sunday.
"This is serious, serious stuff," de Blasio said. "Hottest it's been in many, many years. Let's be safe out there."
Some relief was in sight. A change in the jet stream will bring cooler, less humid air from Canada.
"That will allow much more comfortable air to gradually sweep across the nation's midsection and the Northeast through early week," said AccuWeather's Pydynowski.
Some cities will see the change as soon as Sunday – Chicago, deep into the 90s on Saturday, was forecast for 76 degrees Sunday.
Monday's forecast for Washington calls for a high near 91 with a heat index approaching 100. But with storms approaching, Tuesday's high is expected to drop 10 degrees.
Police in Braintree, a few miles south of Boston, tapped Facebook to try to leverage the heat into something positive.
"Due to the extreme heat, we are asking anyone thinking of doing criminal activity to hold off until Monday," the post said. "Conducting criminal activity, in this extreme heat is next level henchmen status, and also very dangerous.
"Stay home, blast the AC, binge Stranger Things season 3, play with the face app, practice karate in your basement We will all meet again on Monday when it's cooler."
This article originally appeared on USA TODAY: Heat: Triple-digits sizzles across much of USA