In the Southwest, extreme heat watches threaten highs up to 114 degrees from Tuesday through Thursday

Official reports say the brutal heatwave has claimed at least 25 lives and placed 40 million people under heat alerts across the East Coast, the Southeast, and the Southwest.

Over the Fourth of July weekend, heat index values were expected to reach 100 to 105 degrees Fahrenheit, prompting more than 378 people in New York City to visit emergency rooms for heat-related illnesses.

In the Southwest, extreme heat watches remain in effect from Tuesday through Thursday, with temperatures expected to reach 114 degrees Fahrenheit in parts of Arizona and California.

At the same time, severe storms knocked out power to more than 215,000 customers in Michigan, 151,700 in Pennsylvania, and 94,200 in New Jersey, according to PowerOutage.us.

Meanwhile, forecasters expect heavy rainfall of up to 3 inches across parts of New York from Sunday through Tuesday.