Powerful storms and high heat forecast Monday; Chicago recovers from record rains: Updates

Powerful thunderstorms and high heat were in the forecast again Monday across much of the country.

Scattered strong to severe thunderstorms, accompanied by heavy rainfall, may develop across the eastern U.S. and parts of the northern Great Plains, the National Weather Service said. Almost 100 million people live where severe weather is possible Monday, according to the Storm Prediction Center.

Meanwhile, extreme heat will be the main story in parts of the South and the West, where highs will soar near 100 degrees in some areas.

Monday's weather follows a wild day of weather on Sunday, which included record rainfall and flooded streets in Chicago.

Threats of thunderstorms, hail, tornadoes

The threat of dangerous and severe thunderstorms will extend across parts of the Northeast and mid-Atlantic as well as the north-central portion of the country on Monday afternoon and evening, forecasters said.

Large hail, damaging winds and a chance of a small number of tornadoes are forecast for the regions, AccuWeather said. Some storms will produce lightning strikes and wind gusts 60 to 70 mph, AccuWeather meteorologist Alex DaSilva said.

Accuweather meteorologists warned those celebrating Fourth of July festivities outside to move indoors at the first sign of a thunderstorm.

There have been over 1,000 reports of damaging winds alone from severe weather spanning Thursday through Sunday, according to the National Oceanic and Atmospheric Administration.

West, Southeast under intense heat

While temperatures across much of the South have begun to cool down, parts of the Southeast and West remained under heat alerts Monday.

In the Southeast, heat indices could approach 105-110 degrees, and high temperatures could reach the mid-90s, "which can be dangerous if spending an extended amount of time outdoors," the weather service warned. Heat advisories were in effect for the coastal Southeast on Monday, all the way from Virginia to Florida.

In the West, excessive heat warnings were issued for the Desert Southwest region, including portions of Arizona and California, where many spots were forecast to top 110 degrees. Parts of the Los Angeles metro area were also under heat advisories Monday.

The weather service in Los Angeles said heat exhaustion and heat strokes are possible during hot and humid weather. Residents were advised to "be on guard" and avoid leaving children, pets, and elderly people in hot cars, the weather service in Los Angeles said.

High fire conditions are also expected. The Angeles National Forest warned that fireworks are a risk and prohibited on federal public lands.

The heat is expected to last through the week, forecasters said. "Heat-related danger remains elevated due to the longevity of this heat wave," the weather service said.

Record rain flooded Chicago on Sunday

Heavy rains flooded Chicago streets Sunday, trapping vehicles and forcing NASCAR officials to call the Xfinity Series race scheduled to run through the city's downtown.

The weather service reported that some areas had received over 7 inches of rain and several roadways remained flooded. The Illinois State Police said portions of Interstate 55 and Interstate 290 had been closed because of flooding, and at least 10 cars were trapped in water on Interstate 55, WLS-TV reported.

Trains had also stopped in some parts of the city.

NASCAR officials had planned to complete the last half of an Xfinity Series race Sunday morning after it was canceled Saturday because of lightning. But heavy rain Sunday caused officials to cancel the race and declare Cole Custer the winner.

Chicago officially received 3.35 inches of rain on Sunday at O'Hare Airport, which surpassed the city's previous daily record rainfall of 2.06 inches, set on July 2, 1982. Chicago-Midway Airport also received 4.68 inches of rain.

"DO NOT drive or walk across flooded roads," the weather service in Chicago tweeted. The weather service also warned that the flooding could be "life-threatening" because of multiple impassable roads, overflowing creeks and streams and flooded basements.

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Contributing: Jeanine Santucci, USA TODAY; Associated Press

This article originally appeared on USA TODAY: Monday weather updates: Powerful storms in East, heat in South, West