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All's Fair in Art/Science of Region's Forecasting

October 26, 1986|DICK RORABACK | Times Staff Writer

Long before the barometer was begat, man could tell it was going to rain.

The Cherokee, discerning a ring around the moon, would bid his squaw batten down the wigwam. The ancient mariner would drum a ditty into the ears of his oafish apprentice until the lad fair mumbled it in his sleep: "Red sky in the morning, sailor take warning. . . ." A squall rolling in from Iowa? Uncle Phil's old shrapnel wound would know it before he did.

Folklore, they called it. And it worked. It dictated the tempo of crops, the course of battles, the discovery of America (albeit on the way to Calcutta).

It worked, that is, for the short run. For long-run forecasts, man had to wait for the U.S. Weather Service. Depending on how long the run, he is still waiting.

Expectations Outstrips Technology

Today's forecasting capability is considerably more sophisticated than Uncle Phil's hip. As usual, though, man's expectations outstrip his technology.

A man in Downey, planning a neighborhood barbecue, calls the USWS. What he wants to know--demands to know--is whether it's going to rain in his backyard at 5 p.m. two weeks from Saturday.

"We can't tell him with 100% accuracy," says Art Lessard, Southern California weather chief. "I seriously doubt if we'll ever be able to tell him."

The art/science of forecasting, nevertheless, is making progress--imperceptibly, perhaps, to the man on the suddenly soggy street, but measurably to the meteorologists.

"Put it this way," Lessard says: "The five-day forecast that's issued today is as accurate as the three-day forecast was 20 years ago. The 10-day mathematical model of the atmosphere is roughly equivalent to the five-day forecast of the '60s."

Lessard, however, an acknowledged expert, is the first to admit that even in the '80s, we know more about Buddy Ryan's 46

Defense than we do about "Mother Nature's game plan."

Moreover, even the standard 12-hour forecast is widely misunderstood. "That '30%-chance-of-rain' " Lessard says, "simply means that during that period of time you have a 30% chance of getting wet."

Fair enough, even warmer, but even at that, the USWS can't win. Should the sun shine, as is probable, you'll likely wonder why they even bothered saying "30%." And if you're rained upon? "How come those turkeys said only 30%?"

The percentage of weather data-gathering sources, meanwhile, has increased a hundredfold in the recent past, almost to a Winchellian "Mr. and Mrs. America and All the Ships at Sea." The weather services analyze data dispatched by everyone and everything from satellites to a guy in Agoura with a bucket on his back lawn. Lessard ticks off his sources:

--Satellite pictures are transmitted to Earth stations every 30 minutes. "A lot is inferred from the pictures: cloud movement, type, height, temperature. . . . Certain scanners now give you a vertical profile of what's happening with humidity, temperature, wind."

--Weather balloons all over the world, released twice daily, "rubber, helium-inflated, carrying instrumentation. Some of them go up to 140,000 feet. When they leave the ground they're six feet in diameter. By the time they burst, at the top of the atmosphere, they're the size of a three-story house."

--Airports, airline pilots and the Federal Aviation Administration, which swaps data with the USWS.

--Ocean-going ships, 1,000 miles out or more; instrument-packed buoys, several hundred miles offshore; closer in, small-boat enthusiasts sharing their observations.

--"And locally? I have a guy in a bathing suit with a yardstick."

The USWS strategically spots weather stations across varying terrain.

The service also enlists "paid observers," for whom instruments are supplied, installed, maintained. "A lady and her husband, in a small house in Banning Pass, call in half a dozen times a day with cloud height, visibility, etc.," Lessard says. "They're paid so much for each observation.

"Then we have 'cooperative observers,' who phone in a lot of the information you read in the daily paper.

"They're volunteers--ordinary people who are weather hobbyists. They do it just for the sake of the science.

"There are 2,400 of them in the U.S., 800 in California alone. I don't care where it is, there's a co-op somewhere near--on a mountaintop or in the depths of Death Valley, or it's some little guy sitting on a half-acre who's inherited the job from his father, his grandfather.

"They call in once a day, some reporting everything, others just one thing. Some of them have just the bare essentials; say, a plastic bucket for catching rain. Some have pretty elaborate installations. They'll spend anything from $30 to $3,000.

"They're very dedicated, very conscientious. Sure, you read 'not available' occasionally. Maybe the guy's mother-in-law is visiting and he doesn't want to go home that day. Most always, though, even when they go on vacation they have a backup: a wife, a next-door neighbor.

"They do it for the love of it."

David Bender does it for the love of it, and then some.

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