- The Washington Times - Thursday, January 20, 2000

The nation's weather forecasters have a new supercomputer, and it's almost certain to keep Washington, D.C. and environs from experiencing next winter the kind of tizzy caused by Tuesday's scant snowfall.
Already, however, the dazzling IBM SP computer at Bowie's National Centers for Environmental Prediction, Md., is improving forecasts dramatically.
"It has put us closer to our goal of being America's no-surprise weather service," says John Kelly Jr., director of the U.S. Weather Service.
Well before Tuesday when the computer was declared operational, it facilitated early predictions that a "dangerous storm" off the East Coast will shake 3 to 6 inches of fluff on the D.C. area this morning and "into the afternoon" with "potential for high winds," temperatures in the 20s and "dangerous wind chills."
It's that temperature estimate, though, that might be off a bit. Certain temperature predictions still stymie the 786-processor brain.
Although the computer spits out 690 billion calculations per second and is one of the world's two-fastest brains, it has not yet been fed the new mathematical formula, or "model," that will yield accurate "near ground" temperature calculations. That will be done between September and November.
Lack of the model was the probable cause of problems commuters encountered two days ago from less than a half-inch of snow. The computer's calculations correctly indicated which Washington-area counties would receive snow and how much would accumulate. National forecasts previously could predict the development and movement of weather systems only for state-size areas about as big as New Jersey.
However, the computer-based prediction called for Tuesday afternoon temperatures in the low 30s. "The temperature during the snowfall was in the upper teens and 20s. That makes a big difference in what a tiny bit of snow can do to roads," says Louis Uccellini, director of the environmental prediction centers.
As a horde of motorists noted, at those temperatures tire friction can melt the flakes that then turn to ice.
"If maintenance crews had known in advance how cold it would be during the snowfall, they probably would have been out earlier," says Mr. Uccellini.
That aside, the new computer allows analysts to forecast with greater accuracy than ever events that will occur in six to 10 days. Until now forecasts were limited to two to five days.
Mr. Uccellini explains that the new computer replaces an older Cray C-90 that caught fire some time ago. The new IBM was being assembled at the time, and, until it was finished, the environmental centers were dependent on a patchwork of computers at five centers around the world.
The IBM is being leased for $35 million through 2002. It is five times faster than the Cray and far speedier than the makeshift computer system that replaced it.
When the IBM is racheted to full speed in September it will be 28 times faster, performing an unimaginable 2.5 trillion calculations per second. And since speed in this case aids accuracy it will be a more reliable predictor.

This article is based in part on wire service reports.

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