La Niña is here and no one knows what it's going to do, not even the experts.
In Southern California, we could experience a wetter winter than normal. Or a drier winter than normal. Or rainfall numbers that are utterly average. The probability for each outcome is exactly the same — 33.33 percent — according to Mike Halpert of the National Oceanic and Atmospheric Administration.
"Changes in the Pacific jetstream impact changes in our weather," he tells KPCC.
The La Niña weather pattern, which is characterized by colder than average ocean temperatures in the central Pacific, is the flip side of El Niño, which features warmer ocean temperatures.
La Niña conditions usually means wetter winters in the northern Rockies, Pacific Northwest and Ohio Valley and warmer, drier conditions in Southern California.
"I'm sure that's not what folks in drought-stricken parts of California are hoping to hear, but that is oftentimes what we see," Halpert says.
The current prediction is that La Niña will last through February or March, before ocean temperatures return to normal. After last year's ballyhooed "Godzilla El Nino" didn't pan out, weather prediction agencies may be taking a more careful tack.
"I will say our models are certainly not perfect," Halpert says. "Back in the summer, our models were not implying we would see a La Niña at this time of year. They were off on that. So it gives us a little pause and a little uncertainty as to how long this event will last."
At least Northern California is likely to see more rainfall than normal.