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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

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.

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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).

At the same time--and even more important to human comfort--the terrain immediately west of the slender strip of Southern California beach is by nature (if not preference) dry and desert-like. The seabreeze thus picks up little moisture on its passage inland and leaves our basins and valleys far less humid than is the oppressive East, or even the muggy Midwest.

Which brings us, rather reluctantly, to Florida. On the surface, the entire Gulf and Atlantic coasts--from Texas bending all the way around to Maine--would appear to be beneficiaries of their own benign system, the Bermuda High.

Yes and no, Lessard says. There’s a kicker: “Remember the clockwise flow. While our high draws down cool, moist air--and cold sea--from Alaska, the Bermuda High draws up warm moist air--and the tepid Gulf Stream--from the tropics.

“Even in, say, February, the water of the Gulf Stream is at 80 degrees. Out here, the water temperature is 56. And that results in a world of difference in the climate you get. Florida sea breezes blow toward the land over the Gulf Stream and become saturated with warm moisture. The interior, of course, is puddled with lakes and swamps. The humidity, then, especially in the summer, can get unbearable.

“It’s not only Florida, either. Houston is awful. All of East Texas. Oklahoma, Kansas, the whole Midwest can be miserably humid in the summer, simply because the Bermuda High brings in warm, humid air all the way to the Rockies. It can extend northward, too--to the Great Lakes, southern Canada . . .

“The whole side of the country east of the Rockies is affected, often adversely, by warm air from the gulf. And the interaction of cool Canadian air with all that moist air is what creates those tornadoes, too, and those thunderstorms. The Rocky Mountains provide a natural barrier for us.”

When searching for the “perfect” climate, then, one might effectively rule out everything east of the Rockies. Nevada and Arizona, as everybody knows, are too hot. From San Francisco north, the Aleutian Low plays havoc with the weather.

Which leaves Southern California . . .

So everything’s cool here, right? Dry in the summer, moderate in the winter, with a little rain in the off-season, just to keep the pot honest, while the Pacific High goes on its annual holiday . . .

“Not quite,” laughs Lessard, “though it’d make our jobs as forecasters a lot easier if it were always so.”

Even on the clear complexion of Paradise, it seems, there are just enough blemishes to give our face some character. The Santa Ana, for example. The undulating terrain. The Palos Verdes winds. The Catalina Eddy . . .

But first, a word from our sponsor. “What we have here in coastal Southern Cal,” says Lessard, looking fondly toward the sea from the 10th-floor office in the Federal Building in Westwood, “is a rare Mediterranean-type climate”: relatively mild and comfortable all year round; few extremes; hot, dry, sunny summers and a moderately rainy winter season.

“There are only a few places in the world like this: Southern France and Northwest Italy, of course; certain parts--but not all--of the North African Coast; a small area in southeastern Australia and another in southeastern South Africa.

“It’s the type of climate most agreeable to most people, and in truth, there aren’t that many places that have it.”

Unlike other Med-type climes, though, “Southern California has even more to offer. You can pick what you want--an Alpine climate, a desert climate and everything in between.

“You like it cool, you can live by the beach. Warm? You live on the other side of the mountains, in the valleys. Alpine? Move up to Tehachapi or Big Bear, or the Beaumont area overlooking Palm Springs. We have mountains, deserts, canyons, long stretches of beach.

“Sure, I miss the seasons back East. It’s been said that ‘People without seasons will never develop character,’ but that must have been written by an Easterner. We have as much character as anyone else; it’s just different.

“In New England in the winter, maybe they work a little harder--but they have to. You gotta keep moving or you’ll freeze!

“In any case, we do have seasons here: the dry, and the wet, say from October or November through March, when the low from the north encroaches.”

Further, a Southern Californian, if he wishes, can change seasons at whim. Nor is it necessarily as complicated a maneuver as a drive from the Civic Center to Lake Arrowhead and down into Palm Springs. “On a hot July day,” Lessard notes, “you can drive from the Valley, where it’s 105 degrees, to the other side of Sepulveda Pass, where it’s 75--and you’re only talking five or six miles.

“The Pacific High really controls everything that happens on the West Coast, but it’s the terrain that makes it interesting.”

And the sun that makes it salubrious. Even Lessard, a lifelong weather nut, marvels at the figures. “Did you know,” he asks, “that averaging out the whole year, in Los Angeles the sun shines 73% of the time possible? That’s counting not only rainy days but the times the clouds blot out the sun. And in the summer, it’s 83%. Barring desert country, it’s the highest in the United States.”

That’s the good news. The bad news is rain, fog, wind and the odd scorcher, elements thrown in by Mother Nature to keep us from getting bored, if not smug.

Rainfall in Shangri-La averages 15 inches a year (by comparison, Boston averages more than 40 annually; Miami wallows in five feet a year). Anticipating both oldtimers’ hackles and carpetbaggers’ howls, it should be pointed out that our annual rainfall varies wildly: Los Angeles got 38 inches of precipitation in 1883-84; in 1960-61, the grand total was four inches. “I’ve looked at this for years and years and I can’t come up with any trend or cycle,” Lessard confesses. “It appears to be totally random.”

So, indeed, is the topography, which has a great deal to do with whether your roof leaks or your dichondra droops.

What, Lessard was asked, are the wettest locales in Southern California?

“The mountains, of course--any of the peaks around here. Say a storm comes through today and we get three inches downtown--which would be a mess. Up on Mt. Wilson, that three inches might be 25.

“The reason, in layman’s terms, is that moist air that’s flowing upward condenses. You move a parcel of moist air up to a certain altitude and it turns into a cloud.

“The sides of the mountains that face the sea are the wettest spots; that’s where you see the clouds, incidentally. The other sides of the mountains could be bone dry, because most of the clouds get ‘rained out’ on the windward side. That’s why it can snow like hell on the way from Sacramento to Reno, but on the other side of the Sierra there’s nothing on the ground. That’s what meteorologists refer to as a ‘rain shadow.’ ”

From West L.A. down to Long Beach, the average rainfall is 12-15 inches annually. In the San Fernando Valley-Newhall area, which is higher, it’s about 16. “Go east of Pasadena in the foothills and the average is 40,” Lessard says, “and you’re not talking that many miles, either.”

Not that it necessarily rains more in the valleys. “If a storm’s coming from the west or northwest,” says Lessard, “it may hit some mountains and dissipate before hitting the San Fernando Valley. In any case, it depends on just where you live in any of the valleys. People up in the hills in Sherman Oaks, for example, often get a lot more rainfall than folks in Van Nuys, just a couple of miles north, because of the uplift of the air as it ascends the foothills.”

There’s a lot more to our weather, of course--all those permutations and combinations that contribute to our exquisite and infinite variety. Bear with Art Lessard, then, for another round; even God took six days to create Southern California and the Terra Incognita beyond.

Why, for example, are our valleys both the hottest and coldest places to live? What exactly is the infamous “Santa Ana” that makes our pants cling to our legs? What--or who--is Catalina Eddy?

See related story on East Coast weather on Page 16.

Continued next Sunday.

Five Fascinating Facts About the Weather in Los Angeles

- The sun shines 73% of the time on the Los Angeles Basin.

- Santa Ana winds blow from the north, not from Santa Ana.

- Los Angeles gets 15 inches of annual rainfall; Miami gets 60.

- Temperatures can vary 30 degrees in only five miles.

- The valleys are the hot spots. Cold spots? Also the valleys.


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