Predicting twisters relies on people, technology

April 9, 1998
Web posted at: 10:48 p.m. EDT (0248 GMT)

PEACHTREE CITY, Georgia (CNN) -- When a tornado is coming, timely warnings can be the difference between life and death. But as recent experience has shown, the science of forecasting twisters can sometimes be imperfect.

Thursday night, residents of Alabama, Georgia and Mississippi all had about 15 minutes of warning to take cover when a deadly storm ripped through. But last month, when another fatal twister struck North Georgia, warnings weren't issued until the damage was already done.

The key instrument used by the National Weather Service to track storms and predict when tornadoes are about to touch down is Doppler radar.

Doppler radar allows more accurate predictions of tornadoes

Depending on where a storm is located, one of 119 radar towers across the country measures conditions inside the storm, including shifting winds and temperatures that could signal a tornado.

Within a year, the National Weather Service hopes to have new technology online that could provide more advance notice that tornadoes are likely to form. It will use three-dimensional computer models that will look at past twisters to signal when conditions are ripe for another tornado to form.

Doppler radar tower

"One of our newer systems that we're expecting will kind of put all of these things together. We'll be able to see the radar on one screen, the satellite will be on a screen and then the capability of composing the warning will be right there too," says Barry Gooden, a meteorologist with the weather service office in Peachtree City, Georgia.

Once in place, a computer-activated voice will be able to instantly provide warnings as soon as they are issued. That system will replace human beings who in one recent day had to generate 183 warnings at the Peachtree City office.

But forecasters say that when it comes to thorough storm predictions, technology alone can't replace people on the ground. A network of volunteers, called weather spotters, phones into weather service offices and tells them what is happening as severe storms roll through.

"The radar can just show us what a storm is capable of doing and what it might be likely to be doing. The people that are underneath the storm can tell us exactly what it is doing, and that's very important in the warning process," says Matt Sena, a weather service meteorologist.

Correspondent Ann Kellan contributed to this report.

Related stories:

• Tornado injures 4 in central Illinois - April 8, 1998
• Minnesota seeking tornado-disaster relief - March 31, 1998
• One dead from Minnesota twister - Mar. 30, 1998
• Federal officials to assess Minnesota tornado damage - March 30, 1998
• Tornado-ravaged schools reopen in Southeast - March 27, 1998

Related sites:

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• National Weather Service
• National Severe Storms Laboratory

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