The U.S. Climate Prediction Center issued an El Niño watch Thursday, predicting a 50 percent likelihood the weather phenomenon will develop this fall.
While 50 percent sounds like a flip of the coin, it's actually a higher than average likelihood because there are three possible outcomes, not just two: El Niño , La Niña and neutral, which is the condition we're in currently.
El Niño is a warming of ocean temperatures in the tropical Pacific that occurs about every four to 12 years. It can cause above-average rainfall in San Diego as well as potentially damaging waves along the coast. The event can last from 9 months to two years.
“One thing that we typically get with an El Niño is more of these pineapple express storms,” Edward Aguado, professor of geography at San Diego State University, recently told KPBS.
“So instead of our usual cold storms that come out of the golf of Alaska, we get systems that flow up from Hawaii.
“The storms are warmer so they bring less snowpack — you get more in the way of rain than you do of snow,” he added.
It doesn't always guarantee a wet year, said Aguado. During the last El Niño in 2010, San Diego received 10 inches of rain, which is average, but it produced a significantly stronger than usual wave energy, causing 36 percent more erosion along California's shorelines than an average winter.
Major El Niños can bring significant rainfall, such as in 1997-1998 when the San Diego received 17 inches of rain; In 1993, El Niño was credited with dumping 18 inches at Lindbergh Field.
