A rare third year of La Niña is on deck for California, forecasters say.
After the last major El Niño event, last year’s was not nearly as intense and the next year will likely have a more normal El Niño.
This El Niño event is rare in the 20th century.
“We had a very unusual first year El Niño in the ’90s,” said meteorologist David Janssen at the National Weather Service in Oxnard. “It probably was the strongest El Niño that’s occurred on the West Coast since about 1851 and probably since the ’40s.”
A large El Niño, when the temperature anomaly of the tropical Pacific Ocean is large enough, favors warmer-than-normal conditions in the central and eastern U.S. This can include wetter-than-normal conditions in inland areas that could be accompanied by drought in California, Arizona, and other western states. La Niña, on the other hand, is a smaller-scale climate oscillation that tends to favor cooler-than-normal conditions in the eastern U.S. La Niña happens when the temperature anomaly of the tropical Pacific Ocean is moderate. In a La Niña event, wetter-than-normal conditions are often associated with a wetter-than-normal precipitation pattern throughout the western U.S., but there’s nothing unique about this El Niño.”
Janssen described a typical La Niña event as typically featuring less than an inch of rain in San Diego County each year. It’s been wetter-than-normal this winter, with more than 5 inches in parts of Riverside and San Bernardino counties and even 6 inches in parts of Ventura County.
In El Niño years, the central U.S. gets 3 to 5 inches of rain, but the storms tend to have strong winds and dry out the southern U.S. in much the same way that it does for hurricanes.
“What we’re seeing in California is a big dry storm that brings a lot of moisture into the state. We’ve had a lot of rain, in fact, we’ve had about 3 and 1/2 inches [of rain] in San Diego County just this week,” Janssen said. “We haven’t had that