RELEASE: 00-140

It’s been a year almost to the day, but NASA researcher Steve
Goodman still hasn’t forgotten May 3, 1999.

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

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

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

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.

More about the Global Hydrology and Climate Center

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.

— 30 —


Steve Roy

Media Relations


(256) 544-0034


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May 25, 2000