A volatile spring weather pattern is putting much of the United States on alert this week, with severe storms and flash flooding threatening parts of the Plains and Midwest while an early-season heat wave grips the East — even as snow falls in parts of the Rockies.

What's happening?

According to USA Today, forecasters said Tuesday that severe overnight thunderstorms could affect millions of people from Texas across the Midwest and into the Ohio Valley. The biggest threats include damaging wind gusts, large hail, and rounds of heavy rain that could quickly trigger flash flooding.

At the same time, much of the eastern half of the country is sweltering under a powerful ridge of high pressure. Readings in the 90s were nearing record territory in cities along the I-95 corridor and in parts of New England.

New York City and nearby areas remained under a heat advisory through Wednesday evening, with heat-index values close to 100 degrees in some locations, USA Today reported.

Farther west, conditions look entirely different. Higher elevations in Colorado, Wyoming, and Montana were forecast to receive several inches of late-season snow, while the Plains continues to deal with tornado-producing storms, including a long-track tornado in Nebraska Monday night.

Why does it matter?

This kind of coast-to-coast contrast matters because it creates multiple threats at once. Heat can quickly become dangerous, especially in cities where concrete and pavement trap warmth and push the heat index even higher.

Storms in the Plains and Midwest bring their own serious hazards. Tornadoes, hail, and intense wind can destroy homes, damage cars, flatten farm buildings, and knock out power, as seen in reports of snapped poles, overturned vehicles, and wrecked structures along recent storm paths.

The unusual setup also highlights how quickly spring weather can swing from one extreme to another. According to USA Today, a strong jet-stream pattern is helping Gulf moisture run into lingering polar air, producing snow, heat, and severe thunderstorms at the same time.

What's being done?

Weather officials are tracking the pattern closely as the main storm system shifts east later this week. That could spread showers and thunderstorms into the Mid-Atlantic and Northeast, where dangerous heat has already put pressure on residents and local agencies.

Cities in the hottest areas have already opened cooling centers, giving people a place to find relief from rising temperatures. Public officials are also reminding residents to drink water, avoid strenuous outdoor activity during peak heat, and check on older adults, young children, and others at higher risk.

In places expecting snow at higher elevations, travelers may also need to prepare for rapidly changing road conditions. With heat, hail, flooding, and even snow all in play, flexibility and up-to-date weather information are especially important this week.

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