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Long-term tornado forecasts could bring benefits, drawbacks, experts say

On the morning of May 20, 2013, hours before a powerful tornado carved a path through Moore, Newcastle and south Oklahoma City, weather forecasters told residents to be ready in case a tornado spun up.

Now, teams of researchers across the country are working on methods for giving residents the same kinds of warnings several days or even weeks ahead of time.

Researchers say that kind of advance notice could give emergency managers time to remind residents about the importance of preparing for tornadoes. But some experts worry long-term forecasts could also give residents a false sense of security during tornado season.

"We seem to want absolutes, and I understand that," said Michelann Ooten, deputy director of the state's Emergency Management Department. "You're dealing with science and a phenomenon here that doesn't always follow absolutes."

Victor Gensini, a meteorology professor at the College of DuPage in suburban Chicago, is one of several researchers across the country working on methods for making long-term tornado forecasts. Gensini and his team recently noticed an "atmospheric fingerprint," a certain pattern that appears in the jet stream shortly before severe weather.

By anticipating that fingerprint, Gensini and his team are developing tornado forecasts as far as two or three weeks in advance. Last year, Gensini used the pattern to predict tornado activity across the United States. The forecasts were accurate 10 out of 15 times.

The technique is in its early stages, Gensini said, and so far, the team has only developed forecasts for the entire United States east of the Rocky Mountains. But with more research, Gensini thinks those forecasts could be narrowed down to an area covering one or two states.

In Oklahoma, researchers at the National Oceanic and Atmospheric Administration's National Severe Storms Laboratory in Norman are working on a similar project. Researchers there hope eventually to be able to issue tornado forecasts for an entire season.

Although the team has made progress, that goal is still a long way off, said Harold Brooks, the laboratory's senior research scientist.

"We aren't seeing things beyond about two weeks," Brooks said. "Somebody's going to have to get a whole lot more clever."

Aside from giving residents and emergency managers longer to prepare for storms, long-term tornado forecasts could also give forecasters an opportunity to remind people about the importance of tornado preparedness, Brooks said. Even if the quality of those forecasts isn't good at first, the fact that they exist at all could encourage residents to come up with a plan for where to go during a tornado.

Danielle Nagele, associate program officer for the National Academies of Science, Engineering and Medicine, said long-term tornado forecasts have several obvious benefits. They could give residents time to put together emergency plans for their families, which makes it more likely that they would make it through a tornado unhurt.

But the same forecasts could also give people a false sense of security during tornado season or, conversely, make people less likely to take tornado warnings seriously, she said.

It's difficult to convey probabilities and uncertainty to the public, Nagele said. Even if long-term tornado forecasts provide accurate information most of the time, they could still inadvertently leave the public with the idea that tornado false alarm rates are higher than they actually are, she said.

For example, if a forecaster predicts a 50 percent chance that tornadoes will occur within a given area in the next two weeks and no tornadoes materialize, a forecaster might not necessarily consider it an inaccurate forecast. But a normal resident might view it as a false alarm, she said.

Likewise, if a forecaster predicts a chance for tornadoes across a large area, residents in one part of that area might consider it a false alarm even though tornadoes did materialize somewhere else.

An increased sense of false alarms is a problem, Nagele said, because it leads residents to take weather forecasts less seriously and makes them less likely to take action when tornadoes do arise.

In 2014, Nagele was a part of a team of researchers that looked at how residents in tornado-prone areas reacted to tornado warnings. The study, which was published last year, concluded that residents in areas with a high rate of false alarms are less likely to take any action at all during a tornado warning. In particular, those residents are less likely to take shelter during a tornado, according to the study.

Ooten, the state emergency management official, said long-term tornado forecasts could give state and local emergency managers a chance to position equipment and other resources like bottled water well before a storm develops. It could also give the department a better chance of making sure its employees are out of harm's way, she said.

"The more knowledge we can have, the better," she said.

But Ooten worries that those forecasts could also give Oklahomans the false impression that they didn't need to worry about tornado preparedness. If residents see a two-week forecast that doesn't include tornadoes, they might put storm safety out of their minds for the next two weeks. In reality, Ooten said, it's important for Oklahomans to be weather aware all the time, especially during tornado season.

No matter what's in the forecast, it's important for all Oklahomans to have a designated safe place to go during tornadoes. Parents should make sure their children know where the safe space is, she said. By having a plan ahead of time, residents can calmly take action during a storm rather than having to find a space place when a tornado is already on the ground.

"The calm can come by having the knowledge," Ooten said. "You increase your lead time for storms just by being prepared."

Silas Allen

Silas Allen is a news reporter for The Oklahoman. He is a Missouri native and a 2008 graduate of the University of Missouri. Read more ›