As of this writing, Tropical Storm Chris has weakened into a depression in the eastern Caribbean and headed into the warm waters of the Gulf of Mexico. Forecasters at the National Hurricane Center, in Miami, Fla., expect the storm to strengthen somewhat over the next five days but not to reach hurricane force before hitting the Texas/Mexico border area by early Wednesday. This level of predictive power was available before last year's disastrous Hurricane Katrina landfall, but for various reasons government officials delayed an evacuation of the New Orleans area. In this month's feature "It's Hurricane Season: Do you know where your storm is?", authors Robert Gall and David Parsons update us on the efforts to answer this important meteorological question.
We couldn't ask for better guides to take us on a tour of state-of-the-art weather forecasting—particularly that of dangerous storms. Gall is director of the Developmental Testbed Center at the U.S. National Center for Atmospheric Research (NCAR), in Boulder, Colo. And Parsons is a senior scientist at NCAR and co-lead for North American activities under the World Meteorological Organization's Observing System Research and Predictability Experiment.
As they explain, there are three technologies driving the progress of forecasting: supercomputers, satellites, and advances in the scientific understanding of weather dynamics. Supercomputer processing power, for example, is projected to increase 16-fold during the next decade, from today's 2 trillion floating-point mathematical operations per second (FLOPS) to a speed approaching 32 trillion FLOPS, Gall and Parsons note. In the meantime, nine additional advanced weather-specific satellites will likely join the fleet orbiting Earth, providing the first direct measurements of winds and the structure of clouds. And all that data and computer power will be used to better effect, as a result of research already under way on the details of how storms intensify.
To create a three-dimensional weather model of the world, the computer models require in principle that all individual pieces of data for the 1 billion or so points on the globe refer to the same instant in time. In practice, of course, they never do, the authors admit. The process is not straightforward, because the atmosphere is a nonlinear system—it can behave chaotically and, therefore, be impossible to model with complete accuracy. In a nonlinear system, a minor alteration of initial conditions is typically magnified into an enormous change (the "butterfly effect"). And the most nonlinear weather phenomena, and the most difficult to forecast, are low-pressure systems, fronts, and thunderstorms.
Still, meteorologists around the world are hard at work collapsing the margins of error in their predictions. With enhancements in their technological resources, they are trying to arrive at a level of certainty about storm behavior that will soon enable them to make pinpoint forecasts of large storms, such as killer hurricanes, with enough warning time to allow officials and the public, in general, to take the measures necessary to prevent dramatic loss of life and property as much as possible. The hope is that, at some point in the future, the days of Katrina and her vicious relatives will be numbered as killers.
Mark Twain once famously remarked that "everyone talks about the weather, but no one ever does anything about it." That's becoming less and less true all the time—as we all realize that we must support the efforts of those who really are trying to do something about it.
[Editor's Note: For more information on the science of weather prediction, see http://www.ucar.edu/research/prediction. For up-to-the-minute information about the current hurricane season, as well as historical data about past storms, see http://www.nhc.noaa.gov. And read our Tech Talk on submitting your comments to the Federal Communications Commission on how the U.S. government should prepare for the next killer hurricane at: http://www.spectrum.ieee.org/jul06/comments/1461.]