HOW STORMS FORECAST CENTER GREW

In the early 1950s, a small group of National Weather Service meteorologists began issuing tornado and thunderstorm forecasts. By 1954, the group moved to Kansas City - a communications hub near tornado alley - and became the National Severe Storms Forecast Center.

At that time, meteorologists worked with primitive computers. "You were limited in how much of the physics of the atmosphere you could actually model because of the limitations of the computer," says Frederick Ostby, director of the forecast center. As the computers "got bigger and faster the modelers were able to get a more realistic representation of the atmosphere, so the accuracy improved gradually over the years.

"The biggest leap forward probably came with the advent of the satellite," he says. "And when we had the stable geostationary satellite in the early- to mid-'70s, we could actually see what was going on. You didn't have to wait for an observation from this airport or that airport."

Today, 40 full-time meteorologists work three shifts seven days a week searching data for severe weather across the US. It's a tough job because "we're working on a scale that is so small ... we're trying to find a tornado that's less than a mile across," Mr. Ostby says.

Tornado statistics over the years illustrate the center's effectiveness.

In the '30s, 1,685 tornadoes were spotted, and tornado deaths totaled 1,947. By the '80s, forecasters logged 8,194 twisters and only 520 fatalities.

Ostby says the number of tornadoes hasn't increased: "I believe it's mostly that we're spotting them better."

Despite advances in weather forecasting, tornado spotters - trained people who go out with two-way radios looking for black swirling masses of air once a tornado watch is issued - still exist and will for a long time, he says.