SAN JUAN CAPISTRANO — Larry Norton became interested in the weather when his grandmother gave him a barometer for his 10th birthday.
"Every day I looked at it and tried to predict the weather," the 48-year-old county park ranger says. He recalls watching the barometric pressure plunge whenever a hurricane swirled toward the Long Island home where he grew up.
Norton's barometer has survived the years, albeit with a few dings and some repair work. It's one of several instruments he uses to gather weather data at his San Juan Capistrano home.
But why bother with weather instruments when radio, TV and newspapers will inundate you with weather forecasts, updates and replays?
Predicting the weather might be more logically left to the high-tech snooping of Dr. George and Johnny Mountain.
Yet weather patterns continue to interest amateur U.S. meteorologists, despite the ubiquitous presence of the pros.
"Sometimes the subtleties are the real sexy things of life," says Fred Gadomski, an instructor in meteorology at Pennsylvania State University. "You'll notice patterns, trends, and they will prompt questions. The most fundamental step of science is observation."
Thousands of amateurs maintain small weather stations at their homes. Their observations are the basis for media reports. Even with modest equipment, amateur meteorologists find satisfaction and purpose in their efforts.
The federal government relies upon volunteer amateurs, who are called cooperative climatological observers by the National Weather Service. Other amateurs, frustrated at not being able to take part in the Weather Service program, formed the Assn. of American Weather Observers, P.O. Box 455, Belvidere, Ill. 61008, (815) 544-5665.
The group has 2,000 members nationally, says Steve Steinke, its president. The group offers a six-month trial membership, including a monthly newspaper, for $9. The newspaper includes articles on noteworthy observations, evaluations of equipment and procedural tips.
Larry Norton has been recording his weather observations since he was young. Two years ago he joined Skywatchers of California, an affiliate of AAWO. He periodically sends his data to the national group, and these are published in the organization's paper.
Norton does not try to predict the weather. Most of all, he enjoys collecting the data that he believes will help reveal changing weather patterns over time.
"You need records for at least 20 years to get an idea what the weather is like in a particular place," he says.
A well-equipped weather station can measure temperature, moisture, atmospheric pressure, rainfall, and wind direction and speed.
"With those four instruments (an individual will) have a good idea of the weather for the next day," says Dick Walker, technical adviser for Weather & Wind Instruments & Equipment Co. in Inglewood. The company makes weather stations that range from moderately expensive to custom models costing $4,500 to $20,000.
"Most people are getting their weather stations because they're not satisfied with what they're getting" from the news, Walker says, noting that just 10 miles away from one's home the weather may be different because of differences in terrain.
Basic weather instruments also serve on-the-job business needs. Window washers and cranes in seaports are required to have anemometers so they can avoid winds that are too strong.
Walker also notes that weather's impact on hazardous wastes is becoming an increasingly important issue, and weather stations are playing a role in monitoring the movement of these wastes.
Norton maintains a weather shelter in his yard. A white box with louvered sides houses and protects the equipment: a thermometer that shows the maximum and minimum temperatures during a period, a psychrometer to measure humidity, his barometer and a rain gauge.
The best place for a weather shelter is on level ground, on grass, away from trees and buildings--making an adequate site difficult to find in urban settings.
And there are other obstacles. Norton's homeowners association, for example, will not allow roof mounting of the equipment he would need to record wind speed and direction.
Being so directly exposed to the elements, weather stations sometimes take a beating, even in urban locations. Recently, a surprise windstorm blew Norton's shelter over and broke one of his backup mercury thermometers. Wind instruments, which are often high enough to avoid obstructions, are occasionally hit by lightning.
More critical than having an expensive thermometer is the manner in which it is exposed, Gadomski says. "The best thermometer will give you rotten readings if it isn't placed correctly. The readings should be done in the shade. In sunlight, the sun heats the thermometer."
Dust or dew on the thermometer bulb can also affect readings.