Dangerous heat and early snow: US weather forecast is hot and cold - USA TODAY

Heat advisories, warnings: Millions hit with dangerous heat

Dangerous heat and early snow: US weather forecast is hot and cold

A blast of heat is scorching portions of the Midwest and Northeast Tuesday. Meanwhile, the first snowflakes of the season could hit Montana.
Doyle Rice

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A short-lived but intense blast of heat is scorching portions of the Midwest and Northeast on Tuesday, one that's sending temperatures to "hazardous" levels in cities such as New York, Chicago and Philadelphia.

For some folks, it may be the hottest weather of the entire summer, AccuWeather said, as temperatures top out in the upper 90s to the low 100s with the heat index.

The heat is affecting tens of millions of people Tuesday: As of Tuesday morning, heat alerts were in effect for nearly 61 million people in the Midwest and Northeast. Expanding warnings and advisories were possible into portions of the mid-Atlantic on Wednesday, the National Weather Service said.

Though the heat should break tonight in the Midwest, it was forecast to hang on in the Northeast into Wednesday, forecasters said.

Meanwhile, the first snowflakes of the season could reach the higher elevations of northwestern Montana on Wednesday, the National Weather Service said.

The weather service warned people who planned to spend time outdoors in Montana to beware of hypothermia.

Hazardous heat

The magnitude of the extreme heat in the Midwest and Northeast, combined with oppressive warmth at night, will lead to hazardous conditions, particularly for the elderly and those with pre-existing health conditions, the weather service said.

People in Chicago, for example, can call 311 to request well-being checks for elderly friends or family members, or for information on finding the nearest cooling center.

Residents also were reminded to drink plenty of fluids, stay in an air-conditioned room, and stay out of the sun.

And importantly, people were warned to not leave children and pets in unattended vehicles. Car interiors can reach lethal temperatures in a matter of minutes, the weather service said.

Short-lived heat

The spell of record heat will be relatively short-lived as a cool high-pressure system settling into southern Canada is forecast to send a cool and damp air mass into the Great Lakes on Wednesday. It will quickly spread into New England on Wednesday night and reach into the mid-Atlantic by Thursday morning behind a sharp cold front.

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A second cold front that was expected to pass through by the weekend will prove the death knell – for now – to the summertime weather as the calendar turns from August to September, according to Bill Deger, AccuWeather senior meteorologist.