Flight cancellations multiplied across the US Midwest and East Coast as violent storms and an expanding heat wave threatened power grids and temperature records for a thousand miles.
More 165 million people were under some sort of heat warning or advisory by Monday afternoon, with the bulk of them caught in an unbroken swath of torrid weather stretching from the Great Plains to the Great Lakes and the Deep South, according to the National Weather Service.
At the edges of that footprint, Philadelphians braced for quarter-sized hail while the Chicago Transit Authority suspended service on some commuter rail lines to clear debris from tracks following destructive storms. More than 640 flights were canceled at Chicago’s two main airports, according to FlightAware.
Amtrak sojourns through Chicago, St. Louis, New Orleans and Houston all faced delays as track-warping heat forced trains to go slow, the rail operator said.
Extreme temperatures this week are set to cover “a big area across the middle section of the country,” said Bob Oravec, a senior branch forecaster at the US Weather Prediction Center. “There is still a lot of heat through the Plains for the first half of the week. Then the heat will definitely shift westward.”
St. Louis is expected to reach 91F (33C) on Tuesday, which will feel closer to 100F with the humidity, while Dallas is on track to reach 103F with a heat index of 111F, the weather service said. Other high-temperature pockets are in Southern California and the Phoenix area.
In the Upper Midwest, severe thunderstorms birthed high winds and tornadoes, knocking out power to more than 515,000 people in Wisconsin, Illinois and Indiana, according to PowerOutage.com.
Tornado warnings blared across eastern Wisconsin, the Chicago suburbs and Northwest Indiana. The US Storm Prediction Center received dozens of reports of destructive winds, downed trees and large hailstones.
“Move to a basement or an interior room on the lowest floor of a sturdy building,” the weather service said. “Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris.”
Across the US, temperature records were set to be challenged in Colorado, Kansas, Oklahoma and the Texas Panhandle as well as across the Gulf Coast, according to the US Weather Prediction Center.
The heat is taxing power grids across the continent. The Southwest Power Pool and the Midcontinent Independent System Operator, which together cover parts of 20 states, warned of spiking demand. Stagnant air under the large high-pressure system may crimp wind-generated power at peak times.
Spot power prices on the Southwest Power Pool’s North hub were elevated Monday afternoon, reaching $441 per megawatt-hour. In MISO territory, prices at the Minnesota hub hovered close to $350.
Through the course of the coming week, the heat will start to shift westward, Oravec said. This will bring a break to the middle of the country, but will likely send temperatures across California soaring.
Temperatures are set to rise 3F to 5F above normal throughout the West, including large parts of California, from Aug. 1 to 5, Commodity Weather Group said. While the central and western parts of the US bake, New York City and most of the Northeast will remain seasonally cool.
Flooding rains are expected to return to parts of New York, New Jersey and Connecticut on Tuesday after repeated storms earlier in the month. Manhattan’s Central Park may see up to three inches of rain, the weather service said, with heavier amounts in the Hudson Valley.
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