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Why Southern California Area Has the Best Weather Under the Sun : Meteorologist-in-Charge Gives Most of the Credit to Eastern Pacific High

October 19, 1986|DICK RORABACK | Times Staff Writer

We suspected it, of course, and reveled in it. Even bragged about it. But most of us never knew why.

Now we know; now, with no fear of contradiction, we can shout it from the house tops--or from the patio chaise longue, whichever comes first:

Southern California has the best weather in the world!

Like most of us in Southern California, the man is from out of state--in his case New Hampshire.

By the nature of his job, his experience and his expertise, he could live, and thrive, most anywhere in the world.

He prefers Los Angeles.

Why? "It's the climate," he says. "I don't like extremes--overly warm and humid in the summer; wet, snowy and cold in the winter. I like a temperate climate, and I love the sun.

"When I first came out here, it was just another job. But the place grows on you. It's where I want to be. I'll retire here."

You've heard it a thousand times--from a neighbor, a colleague; from the butcher, the baker, the cinema maker. Probably even said it yourself once or twice. But you've never heard it from Arthur G. Lessard. There's a difference.

Lessard is the man who knows --the Meteorologist-in-Charge of the National Weather Service in Southern California--and not only does he know the weather's great out here, he knows why .

There's a hero to the piece, of course. There always is. The hero of the Southern California weather story, the Force that is with us, orchestrates our climate from far offshore. Hundreds of miles across, unseen but virtually omnipotent, it keeps us cool while the rest of the country swelters, warm when the rest of the country freezes, dry while America sweats, and calm in catastrophe.

It doesn't have a name, at least not a heroic name, Lysander or Brunnhilde, even Rambo. The weather people know it by the rather pedestrian name of Eastern Pacific High, which is nice, but doesn't quite cut it.

Unnamed and unrecognized by the man in the street, the Pacific High is honored only in the breach, the breach in this case being winter. In what passes for our colder months, the Pacific, like any other self-respecting Northern Hemisphere High, moves south for the rays, leaving the back door open.

Ever jealous, the Aleutian Low makes a pass at the High's turf, only to slink off when the High returns home for the summer. (The Aleutian Low is a villain, the malevolent entity that makes San Francisco a nice place to visit but. . . .)

Back on station, the High picks up where it left off, literally spinning its magic and keeping us free from the rains of Eureka, the twisters of Texas, the humidity of Hialeah.

A splendid scenario, to be sure. Made in Hollywood, but what does the Pacific High do ?

"We don't have a lot of inclement weather here," TV weathercaster Fritz Coleman says, "because God doesn't think we can deal with it emotionally."

Art Lessard has no quarrel with the Almighty, but his explanation for our blessed clime tends a little more toward the pragmatic.

"The major influences on our weather," he says, "are the Pacific Ocean, the terrain, but most especially the Eastern Pacific High."

Deviations and aberrations are due to "Mother Nature's game plan," which the forecasters have yet to solve, if they ever do. But by and large, the High, a semi-permanent fixture in the eastern Pacific, dominates our weather pattern.

Air flows outward and clockwise around a Northern Hemisphere High. To replace the laterally spreading air (nature abhors a vacuum), air from aloft converges and descends. Since it is squeezed into a smaller space, the descending air (like everything else that's squeezed) is warmed up on the way down.

Since the warming of air does not normally produce clouds, clear skies and fair weather are generally associated with regions of surface high pressure. (Conversely, air flows in toward a low. It has to go somewhere, so it rises, expands, cools, condenses, forms clouds. Cooler air has less capacity for holding water vapor, so at the top of a low, the air--often carrying clouds, rain, snow--flows out, and all hell breaks loose.)

Fair--or foul--enough, but if a high appears to guarantee good weather, why is Florida so soggy?

"It's a little more complicated than that," says Lessard, a patient man who loves his work and is not at all averse to interpreting it to the ignorant.

Air flows clockwise around a Northern Hemispere high. So does water, pushed by the wind. In California's case, the seas flowing southward down the coast are cool, coming as they do from the Aleutians area (which, of course, explains why swimming in the Pacific is a lot more bracing than in the Atlantic).

Prevailing winds, usually blowing from the sea to the coast, are cooled by passage over the chilly current as they boogie into Southern California, sweeping through the basin and ventilating what would otherwise be stuffy, torrid summers. (Like an Al Capp Schmoo--all things to all people--our sea breeze also serves as a muffler against chill, the ocean in winter generally being warmer than the land).

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