Weird is a word rarely used to describe the weather in San Diego — especially in October, when warm Santa Ana winds help push the marine layer offshore.
But coastal areas of the city are in the midst, and mist, of an unusual period of thick, come-and-go fog that’s lasted more than a week and will linger for several more days, the National Weather Service said.
The fog was so thick on Saturday it made an 814-foot Japanese aircraft carrier nearly invisible during a port call in San Diego.
The region is experiencing a meteorological chain reaction. A massive high pressure system developed along the entire West Coast, causing temperatures to soar in places like Campo, which hit 102 degrees on Monday. At roughly the same time, sea surface temperatures off San Diego County dropped from the mid-70s to the low 60s. The cool, moist air has been colliding with the dome of heat over land, producing fog.
“A lot of people think it’s unusually cool at the coast right now, but it actually isn’t,” said Alex Tardy, a weather service forecaster. “If you went 1,500 feet above your head, you’d encounter air that’s about 85 degrees. You have to think three-dimensionally to picture it, and that’s not easy.”
As surfers will tell you, it’s also unexpected. Ocean temperatures fluctuate. But such a steep drop in them isn’t that common this time of year.
Tardy says the shift was likely caused by upwelling — a phenomenon in which onshore winds hit the coast at an angle, pushing the warm upper layer of the ocean away from the coast and allowing cooler water to rise to the surface.
