By Annabeth Miller, ShowMe Times Editor

Southeast Missourians may think we have seen some turbulent weather already this spring – but the bad news is that “it ain’t over yet.”

A weather expert with the University of Missouri says that this spring could be stormer than normal. Tony Lupo with the College of Agriculture, Food and Natural Resources in Columbia, says that our spring weather will be affected by La Nina, the same phenomenon that spawned this winter’s snows and ice.

The Midwest found out just how forceful La Nina can be this last weekend. Friday afternoon brought tornado watches, hail and heavy storms throughout Southeast Missouri. Throughout the weekend a deadly swarm of twisters left devastation in up to 15 states.

Storms threatened most of Friday afternoon in the Deter area, and pea-size hail fell at approximately 4:30 p.m. The entire region was under a Tornado Watch until 9 p.m. Friday

The storms storms battered their way from Oklahoma to North Carolina, claiming at least 44 lives, almost half of those in North Carolina. It was the deadliest since Feb. 5, 2008, when 57 died in the "Super Tuesday" election day tornadoes in the Southeast. And that was the highest tornado death toll since 76 died in 1985.

La Niña occurs when cooler than normal water temperatures develop in the Equatorial Pacific Ocean. Lupo thinks La Niña will lead to increased spring and summer thunderstorm activity in states north of Tornado Alley, including Nebraska, Iowa, northern Illinois and Indiana.

Tornado Alley is defined as North Texas, Oklahoma and Kansas. Lupo says that La Niña tends to shift the jet stream patterns northward over the U.S.

In a La Niña season, the jet streams pick up warm Pacific moisture and direct warm and unstable air to Nebraska, Iowa, Illinois and Indiana. Storm systems and fronts tend to follow these streams.

Overall, from Thursday through Saturday, there were reports of funnel clouds in Kansas, Oklahoma, Texas, Arkansas, Alabama, Illinois, Missouri, Mississippi, Kentucky, Georgia, Louisiana, Maryland, Virginia, North Carolina and South Carolina.

“For a thunderstorm to develop, there must be moisture and warm air,” Lupo says. “When the jet stream is farther north, as it is in a La Niña event, you have a better chance of achieving these kinds of temperatures and dew points in these parts of the country.”

In Tornado Alley, Lupo forecasts a relatively calm year. Atmospheric models predict a dryer than normal spring and summer, taking away the fuel for supercell storms, which often spawn tornadoes.