Tornadoes, severe weather to escalate as 'dangerous pattern' evolves over US

Severe weather season is about to shift into high gear as a volatile weather pattern fuels repeated rounds of damaging thunderstorms and tornadoes across more than a dozen states through May.

Through April 18, there have been over 315 preliminary tornado reports across the United States, including deadly twisters that swept across Ohio in mid-March and a recent spate of more than a dozen tornadoes in the central Plains.

AccuWeather issued its initial tornado season forecast in March and called for a number of tornadoes in May higher than the historical average - a forecast that is now coming into focus in both time and place.

This weekend could be the start of a two-or-three-week period of very active weather, AccuWeather Long-range Expert Joe Lundberg said.

A big storm system moving in from the Pacific will emerge over the Plains about April 26-29 which could spark the next big severe weather outbreak. "A warm, moist connection from the western Gulf and Caribbean will meet up with this intense storm and lead to a couple of rounds of severe weather, including several tornadoes," AccuWeather Lead Long-range Forecaster Paul Pastelok explained.

The dangerous weather pattern that will fuel the late-April severe weather is expected to continue as the calendar flips to May.

"It's a volatile time of the year, and that's going to continue right into May," Lundberg said.

Two twisters spinning side-by-side in Akron, Colorado. (AccuWeather/Tony Laubach)

During the first half of May, the bulk of the severe thunderstorms and tornadoes will likely focus on the nation's midsection, including Tornado Alley. The areas at greatest risk include Dallas, Austin, Oklahoma City, Kansas City and St. Louis.

A shift in the pattern during the second half of May will increase the number of severe storms and tornadoes farther east and in the Plains.

The Tennessee Valley, southern Appalachians and parts of the Southeast will have an elevated risk of severe weather during this timeframe, according to Lundberg. Other areas, such as the Northeast and Ohio Valley, should also be on alert for potentially damaging storms.

The three-month span from April through June typically accounts for half of the tornadoes in the U.S. every year, as it is when the ingredients for twisters come together most frequently.

An AccuWeather analysis of data from the Storm Prediction Center found that May 25 is the day with the highest number of tornado reports. Between 1950 and 2020, 649 tornadoes touched down on the date, more than any other day on the calendar.

While tornado activity usually peaks in late spring and early summer, it can occur on any day of the year when the conditions are right.

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