Dawn Patrol:

This week began with a familiar and welcome pattern: warm sunshine, no wind, warm water and some decent waves. It was pretty small at Newport so I decided to make a run down to the Trestles — San Onofre area.

I knew it’d be a foot and a half bigger and maybe I’d run into the “Three Wise Men.”

On a Monday morning everyone would be at school or work and it’d be uncrowded. Or not.

I arrived to find myself with 200 or more of my closest friends. I knew San-O was well-attended seven days a week, but this was like a summer Saturday. And why not? It was a perfect day for surfing. But conditions were about to change.

Do you remember the marketing buzz-phrase from a few years back, “paradigm shift?”

Well, I think I have a practical example now. The next day the onshore wind flow that had been absent for so long finally kicked in.

Just before sunset a few of us met at my friend Jerry’s house on the beach at 56th Street. It was still blowing pretty hard side-shore and you could tell from the sea surface that it had been really howling earlier.

The whole ocean seemed to be racing down the beach as fast as the quickly peeling wind swell rights. It was a pretty warm breeze and at moments it looked like it was going to clock around to offshore.

We sat and debated the wind direction, whether it was coming from west of north or east of north. For that matter, exactly where was north? Captain Gar broke out his magnetic compass to compare to my cell phone GPS and said something I don’t remember about deviation.

Jerry kept mentioning the Big Dipper. One thing we could agree on was that the wind’s churning, or “upwelling” in oceanographic terms, was going to knock down that warm surface temperature.

Later the next morning I was at the pier. The surface was still bumpy from the previous afternoon. The air was a lot cooler than it had been. The side-shore wind was already coming up again. The jets going into John Wayne were landing on runway 1L, so it wasn’t a normal westerly.

I walked into the water a little past ankle depth to get a temperature check. It wasn’t freezing but it was a lot cooler. I stopped by the Lifeguard Headquarters.

“Did you guys get a water temp reading this morning?” I asked. “You don’t want to know.” was the reply.

I said that I did and they told me it was 58 1/2 — down from 59 earlier in the morning, but it had been 68 the day before! Now that’s a dramatic change — board shorts to full wetsuit in less than 24 hours. There were still quite a few surfers out in the choppy wind swell but as I watched with my buddy Rat Jr., it appeared our seemingly endless summer was over.

Sometimes Rat Jr. has a way with words.

“It looks like Fall has fallen,” he told me.

JOHN BURTON’S surf column appears Fridays. He may be reached by e-mail at hot_dogger@mac.com.