NASA Scientist: Lightning Studies May Provide Earlier Tornado Alerts

On that date, more than 50 tornadoes cut a killer swath across the Great Plains of Kansas and Oklahoma. Property damage was estimated at $1.2 billion. More than 40 people died.

In hope of avoiding another May 3, 1999, Goodman and other scientists at the Global Hydrology and Climate Center, managed by NASA's Marshall Space Flight Center in Huntsville, Ala., are studying new methods of predicting severe storms.

And they believe another dangerous element of severe weather may be the key.

Using a combination of ground and space-based weather monitoring equipment, Goodman and colleagues at the National Oceanic and Atmospheric Administration in Washington, D.C., and at MIT Lincoln Laboratories in Lexington, Mass., have documented nearly a dozen cases in which lightning rates increased dramatically as tornadic storms developed.

"Our studies show a very big spike in the lightning's flash rate prior to formation of a tornado," Goodman says. "It's an early clue for weather forecasters to take a more detailed look at other storm characteristics with radar. And perhaps a chance for them to get warnings out earlier, saving more lives."

Goodman's team will present its research to scientists, meteorologists and emergency management officials from around the country at the "National Symposium on the Great Plains Tornado Outbreak of 3 May 1999," which opens April 30 at the Westin Hotel and Resort in Oklahoma City.

Spotting the telltale lightning flashes isn't as easy as keeping an eye on the sky from your front porch. According to Goodman, the type of lightning NASA is researching occurs within clouds, invisible to the naked eye by day. To properly monitor this type of lightning takes special equipment like NASA's Lightning Imaging Sensor, an instrument flying aboard the Tropical Rainfall Measuring Mission (TRMM) satellite launched in 1997. The sensor tracks worldwide lightning strikes and their relationship to storm centers.

Theories linking in-cloud lightning and tornadic storms have been debated for many years, according to Goodman. For decades, meteorologists and scientists pondered the connection. "But they lacked the ability to properly document and map in-cloud lightning," he says. "With the technological advances we've made in recent years, we can see what they couldn't."

Goodman is realistic about the work that remains ahead. "We don't have enough data yet to say how often the high flash rate precedes tornado formation," Goodman says. "But looking at this lightning signature can help pinpoint storms that are likely candidates, and that can make a big difference."

That difference would provide earlier warnings to increase citizens' chance of reaching shelter, and would likely reduce the number of false alarms that go out every year.

"Lead time for tornado warnings is better than it's ever been," Goodman says. "It's gone from eight to 12 minutes nationally. But the false-alarm rate hasn't changed. Only 30 percent of rotating storms ever make a tornado. That leads to a lot of false alarms lulling the public into ignoring the threat."

"It's a question of accuracy," he adds. "The more accurate we are, the more people take the proper response. That's what this research is all about."

Goodman's presentation, "May 3 Tornadic Supercells Viewed from Space During an Overpass of the NASA TRMM Observatory," will be May 1 at 4:10 p.m. CDT. The Great Plains Symposium runs through Wednesday, May 3 -- the anniversary of last year's devastating tornado outbreak.

The Global Hydrology and Climate Center is a joint venture between government and academia to study the global water cycle and its effect on Earth's climate. Funded by NASA and its academic partners and jointly operated by NASA's Marshall Space Flight Center in Huntsville, Ala., and the University of Alabama in Huntsville, the Center conducts research in a number of critical areas. Satellite tracking of hurricanes promises to improve global severe-weather forecasting capabilities; research into lightning activity is providing new insight on tornado formation; and NASA remote sensing technologies explore new ways to improve the health of our cities, aid farm productivity and identify outbreaks of disease.

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