San Diegans could see a dry winter this year as forecasters expect La Niña conditions to return.
“La Niña is when the ocean temperature is colder than usual in the tropical pacific and that’s a long way from San Diego,” said David Pierce, a climate researcher at Scripps Institute of Oceanography. "When the water is cold there, it changes the weather patterns for the whole northern hemisphere and we tend to be drier here in San Diego.”
With emphasis on the “tend.”
Last year was a La Niña year, but you wouldn’t have guessed it looking at the figures.
“That was the wettest La Niña winter we’ve had in 60 years,” said Pierce.
But he says that was an unusual circumstance.
“It’s like loaded dice. Last year was a perfect example, the dice were loaded but we came out with a snake eyes,” said Pierce.
Right now, the temperatures in the tropical pacific are 1.5 degrees lower than normal.
“That’s about a moderate sized La Niña. It’s not the biggest one we’ve had by any means .The last time we had one bigger than this was 10 years ago,” said Pierce.
Normally in a La Niña year we get about seven inches of rain compared to 10 inches a year in a normal year.
“One of the reasons it affects us here, La Niña typically makes the whole southwestern United States dry and we import half our water from the Colorado river, so that’s important to us,” said Pierce.
Another concern is fire danger.
“When we’ve got these dry conditions, fires can be worse. What affects fires is more than how much rain falls this year, they’re also influenced by how much rain fell last year because that’s what makes bushes and trees grow,” said Pierce.