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Science / Medicine : New Weapons in the WEATHER WAR : Storms cause billions in damage every year. Now the weather service is fighting back with a five-year plan to improve forecasting. : Climate: A $3-billion upgrade includes automated data stations and state-of-the-art radar. Predictions of abnormal storms should improve.


At most weather stations in the United States, weather forecasters read temperatures and monitor precipitation several times a day in the same way Thomas Jefferson did, by looking at a thermometer and emptying out a rainfall collector. The radar used for tracking storms and identifying tornadoes dates from the Korean War.

"We are the only group in the country that teaches courses in repairing vacuum tube electronic equipment," said meteorologist Bud Littin "We have to to keep our radar running."

But not for much longer. Beginning this year, the National Weather Service is initiating a five-year, $3-billion program to bring its facilities into the 21st Century.

The improvements will include automation of all weather stations for round-the-clock collection of data, new computer systems for greater localization of weather forecasts, new state-of-the-art radar that will provide saturation coverage of the country and new satellites to supplement the weather service's sole satellite.

"This will be the most revolutionary change since the National Weather Service was founded 100 years ago," said its director, a man with the unlikely name of Joe Friday Jr.

Perhaps the most important improvement will be greatly increased accuracy in predicting abnormal weather events, such as hurricanes.

"The United States has the widest and wildest variety of weather in the world," said Friday, who joined the weather service nine years ago, after 20 years as a weather forecaster for the Air Force, and became director two years ago. "We have more tornadoes, more flash floods and more thunderstorms than any other country."

In fact, each year the United States experiences about 10,000 violent thunderstorms, 5,000 floods, 1,000 tornadoes and several hurricanes--events that together cause more than $30 billion in property damage. And despite the high-tech satellite pictures that appear on the evening newscast each day and the supercomputers that produce most of the forecasts, the weather service by and large monitors storms with equipment that is antiquated.

But the system will also improve everyday weather forecasting.

"Our five-day forecasts now are as good as our three-day forecasts were 10 years ago," Friday said. "With the new system in place, our seven-day forecasts will be as accurate as five-day forecasts are now." Overall, he added, the accuracy of forecasts could increase from the current 85% level to greater than 90%.

For fiscal 1991, the Administration's budget calls for $170 million to begin implementing the program, on top of its normal budget of $300 million.

The first new weather stations will be installed in the Midwest in "tornado alley." California will begin receiving the new equipment in 1992 or 1993, Friday said. The number of forecasting centers in the state will increase from the current two--Los Angeles and San Francisco--to six, with the addition of Eureka, Sacramento, Stockton and San Diego.

For the first time, the lush San Joaquin Valley will have its own station, permitting more precise forecasting for the farming community. Installation of the new radar systems will also improve forecasting for winter storms.

Friday is confident that the changes will yield a marked improvement in service. That confidence is based primarily on tests of prototypes of the equipment conducted during the past two years in Oklahoma City and Denver.

During that period, he said, the accuracy of severe weather warnings has increased from 59% to 91%, while the incidence of warnings that proved to be false alarms has dropped from 60% to 21%. "In Denver, we have not had a surprise snowstorm in the last two years," he said.

Many of the improvements in storm forecasting are based on the use of new, so-called Doppler radar systems that not only show the location of storms, but also reveal the speed and direction of air and water movement within the storm.

The new radar systems, called NEXRAD, use sophisticated computers to measure slight differences in the wavelength of radar bounced off rain particles in the storms. If the water drops are moving away from the antenna, the wavelength increases; if they are moving toward it, the wavelength gets shorter. The amount of the change tells the speed of the water drops.

Currently, tornado warnings are issued only after a visual sighting. The new NEXRAD systems will allow meteorologists to observe tornadoes as they form and to predict their motions.

A total of 160 NEXRAD systems will be installed, 121 to be operated by the weather service and the rest by the Federal Aviation Administration and the Defense Department.

(In a separate development, the FAA is planning to install at least 40 short-range Doppler radar systems at airports to detect "microbursts," the short-lived severe downdrafts that have caused at least two plane wrecks in this country. Eventually, the number of systems may increase to more than 100.)

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