IBM SP with 786 processors installed for US weather forecast

``This new supercomputer puts us closer to reaching our goal of becoming America's no surprise weather service,'' said Weather Service Director John J. Kelly Jr to AP.

``This gives our forecasters more sophisticated models of the atmosphere and oceans, which act as blueprints for upcoming weather patterns,'' he said. ``On a daily basis, we should see a 10 percent improvement in predicting temperatures, humidity and pinpointing when, where and how much rainfall will occur.''

The new computer, leased for $35 million until 2002, provides the basic guidance for forecasts issued by the Weather Service as well as forecasts provided in newspapers and broadcast on radio and television.

Billions of pieces of information on the weather around the world are fed into the computer continually, giving it a picture of current conditions.

The computer then uses forecast models, which are complex sets of mathematical formulas, to calculate how these conditions will probably change over the next few minutes, hours and days. The models understand patterns of weather movement and how one type of weather affects areas nearby. The models are repeatedly updated with new sets of conditions and then run again.

The results of the models are then sent by computer to Weather Service offices around the country, to universities, to private forecasting companies and to foreign weather services for use in developing local forecasts.

The faster the computer runs the more accurate the forecast is likely to be and the longer period of warning meteorologists can give, Kelly said.

Currently, national forecasts are able to predict the development and movement of weather systems about the size of New Jersey two to five days in advance, Uccellini said.

With the new computer, he said forecasts will be able to predict systems as small as individual counties some six to 10 days ahead of time.

Uccellini said the theoretical limit on an accurate forecast is thought to be about 14 days, and for longer periods predictions are more general.

The older Cray C-90 computer had been in use since 1994 and was to be offered to other government agencies when replaced, but it was destroyed in a fire last September.

Fortunately, Kelly said, installation of the new IBM was already underway. Until it could be put into full service, forecast models were run on computers operated by the Navy, Air Force, Weather Research Office and the European Center for Medium Range Forecasting in Bracknell, England, which has the other of the two fastest weather computers in use.