By Skindrud, Erik
Science News , Vol. 150, No. 2
Summer in the southeastern United States can whip up unpleasant, even violent weather-the kind of conditions that organizers of the upcoming Olympic Games in Atlanta would like to disqualify from this month's competition. When tropical storm Alberto swamped central Georgia in July 1994, for instance, 28 people lost their lives and flooding forced more than 30,000 residents from their homes.
Although the possibility of a repeat performance this summer is remote, other types of foul weather present hazards to athletes as well as spectators. Thunderstorms with lightning top the list of concerns, along with the double scourge of severe heat and humidity, which can kill. To deal with these threats, the National Weather Service has developed a system it says provides more detailed-and more consistently accurate-forecasts than any other in the history of weather forecasting.
The cutting-edge system is at least 5 years ahead of what's available in any of the more than 50 regional weather offices today, says Lans P. Rothfusz, chief meteorologist at the Olympic Weather Support Office in Peachtree City, Ga. "We now have a very prototypical office for the future of the National Weather Service."
The Olympics' 29 competition sites, or venues, are scattered across numerous microclimates. Forecasters plan to rely on a two-tiered system to anticipate the weather at each site. They can make a 48-hour forecast for the entire Southeast, then use local data to create customized forecasts that can be updated several times a day.
The Olympic meteorological team wields an unprecedented array of computer power. A Cray C90 Class 7 supercomputer in Eagan, Minn., digests data for the longer-term forecasts, while a very high speed computer called the IBM SP2 is on loan for local forecasts.
The jewel of the integrated system is Eta-10, the computing software designed to predict weather trends over the Southeast. To demonstrate Eta-10's superiority over present systems, Geoffrey J. Dimego Jr. of the National Centers for Environmental Prediction in Camp Springs, Md., points out that the software used elsewhere has a resolution of about 48 kilometers, whereas Eta-10 has an effective resolution of 10 km.
Olympic organizers need timely forecasts for each venue to ensure the safety and comfort of competitors and viewers at the 271 events. The weather team plans to notify officials at each site if one of the following conditions threatens to reach a dangerous level: rain, hail, lightning, wind speed, low visibility, or heat and humidity.
These site-specific warnings are also tailored to each sport. …