More than 85 million Americans were under excessive heat warnings or advisories on Sunday from the Pacific Northwest to the southern Great Plains and on to the densely populated Interstate 95 corridor, according to the National Weather Service (NWS).
Cloud cover increases this evening, and sporadic showers develop in South Central Michigan before moving to the I-69 corridor and Southeast Michigan.
Overnight, milder, more stable air will arrive. Tomorrow will be warmer and sunnier with less humidity. The upcoming rainy period is midweek.
Heatwave in the northeastern US
From Washington to Boston, the EPA issued a warning about "very oppressive" conditions.
Temperatures were expected to surge beyond 90F even in Pennsylvania's Pocono mountains' 1,800-foot-high Promised Land State Park (32C), as per The Guardian.
However, guests said that it was more than bearable because of the forest shade, the cold lake water, and the mountain winds.
The NWS predicted that many record highs will be tied or broken in the US northeast.
Philadelphia was expected to reach 100F (38C) on Sunday, even without taking humidity into account.
It was the longest such sequence since records began in 1931 in Newark, New Jersey, where five days in a row reached 100F or higher.
Boston also broke the previous record high of 98F established in 1933, reaching 100F.
In New York, there was at least one death attributed to the heat. Athletic competitions were curtailed or postponed all around the area.
Officials in Philadelphia declared a heat emergency that would last until Sunday and dispatched personnel to check on the vulnerable population, including the homeless.
The city installed air-conditioned buses at four crossroads and developed cooling facilities.
Forecasters advised people to minimize their time outside, wear lightweight clothes, drink plenty of water, and check on elderly persons and pets.
Boston's mayor, Michelle Wu, issued a heat emergency that would last through Monday and kept 12 cooling facilities operational.
At lower elevations, the heat was already sweltering less than an hour away. The forecast for Sunday in Scranton, Pennsylvania was for a high of 97F (36C) during the day and a low of 70F (21C) at night.
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Scattered showers in Detroit
Warmer and cloudier conditions are expected for Sunday night, with sporadic showers mostly north of 8 Mile Road.
Before sunset, it will be in the 80s, and following, it will be in the 70s, as per Click on Detroit.
It will be warm and largely overcast on Sunday night. Any rain will start to fade and stop around midnight. Lows for the night will be in the 60s.
Most of Monday will be sunny, warm, and pleasant, and as the humidity decreases, it will feel cozy.
The low 80s will be the highs.
The majority of Tuesday will be bright, warm, and fantastic. Low 80s to your 85°F will be the afternoon high.
Wednesday might see another round of showers and thunderstorms. Highs will be warmer and in the mid-80s.
Showers in spots are possible on Thursday. The low 80s will be the temperature in the afternoon.
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