This Just In: It’s Been Hot, Dry and Very Normal

The meteorological season has come to a close, and scientists studying Southern California weather patterns have boiled down reams of data to two conclusions: The last 12 months were warm and, for the most part, dry.

According to the data, the elements in Southern California behaved obediently in the July 1-June 30 weather season, closely following the celebrated pattern of sunshine and more sunshine.

Temperatures peaked in September and October, as they usually do, with the year’s hottest day in Orange County being Sept. 30 at 108 degrees in Anaheim, according to meteorologists at WeatherData Inc., which provides forecasts for The Times. The chilliest day was Jan. 8 with a low of 37 degrees, recorded at the Santa Ana weather station.

This year’s average spring temperature was 63.7 degrees, the 24th warmest spring since 1888. Compared to the average spring temperature during the last 10 years, we were down a few millimeters of mercury, with 64.6 degrees the average for the years 1990-99.

In the words of meteorologist Steve Pryor, “This was not a very remarkable year for Los Angeles.

“Last summer was a little warmer than normal,” said Pryor, a meteorologist with WeatherData. “The winter was normal and the spring was pretty close to normal.”

Rainfall this past winter, though, was down a drop or two, though meteorologists are quick to say they saw that coming because last year was a La Nina year. Normally 12.27 inches of rain dampen Orange County each year. In 1999-2000, only 7.71 fell, based on the average of rainfall at Santa Ana and Irvine weather stations.

La Nina, a phenomenon of cooler-than-normal water in the Pacific Ocean, typically produces drier weather because it creates high-pressure weather systems that park off the coast of Central California. Winds spinning around these systems dry out by compression as they funnel down California’s coastal canyons, leading to less rainfall.

This is the opposite of El Nino, whose higher water temperatures provoke much more rain, as in 1998.

Tentative, long-range forecasts predict El Nino conditions in the spring and summer of 2001, bringing more rain to Southern California by January or February 2002, according to meteorologists from the National Weather Service.

“We’re just beginning to understand how ocean temperatures affect weather, but it seems that the La Nina effect is among the factors responsible for the drier-than-normal weather last year,” Pryor said.

The La Nina effect is predicted to end by December, and Orange County should receive average levels of rainfall next year, according to a long-range forecast by the National Weather Service.

And what about the greenhouse effect and global warming?

Scientists have been warning that temperatures everywhere are rising slightly but steadily because of an accumulation of gases and pollutants trapped in the atmosphere. But Pryor said there may be other reasons for a gradually warming Southland.

“If there’s been a slight upward tick in [Southern California] temperatures in the recent past, it’s because of all the urbanization, the brick and concrete that soaks up heat, the factories that are being built and all the people.”

People, no doubt, who are content to live here for what else? The normal, pleasantly predictable weather.