LaNiña coming with a) less, b) the same, c) more rain

Water-temperature pattern hatching in Pacific similar to last year’s deluges

After enduring the driest stretch of years in our history, and then logging the wettest spell on record this past winter, befuddled Californians have one question on their minds these days: What’s next? In two words: La Niña. But whether the water temperature pattern hatching right now in the Pacific Ocean will leave the Golden State high and dry this winter as it’s often done in the past is anyone’s guess. Particularly since it’s quite similar to the pattern we saw last year, and we know how that turned out.

“There’s no way to know what this winter will be like,” said meteorologist Jan Null with the

Golden Gate Weather Services in Saratoga. “I can’t tell you and I don’t think anyone else can. The answer, I’m afraid, is: Wait and see.”

Even the federal government’s sharpest weather minds say the mild La Niña they’re anticipating could bring us less rain than normal, more rain than normal or just a normal amount of rain.

“We’re kind of shaking our heads a little bit, too,” said Mike Halpert, deputy director, National Oceanic and Atmospheric Administration’s Climate Prediction Center, during a press conference Thursday announcing its winter outlook report. “There’s no way to say if you’ll be on thewet side or on the dry side in California. Plan for it all.”

Here’s the problem, says Null: Storms are fickle. An El Niño is spawned when the eastern tropical Pacific is warmer than normal and it typically means more rain for California and less rain for the Pacific Northwest. The cooler LaNiña is the opposite, often drying out California but leaving it wetter up north. This year’s mild La Niña is now expected to result in equatorial ocean temperatures - 0.5 degrees C belownormal this winter.

The problem is, no two weather phenomena are identical. And historically, California has seen very dry El Niño years and very wet La Niña years.

In otherwords, nomatter how much time you spend trying to figure out what’s coming our way this winter, there’s a very good chance you’ll be proved wrong.

“A third of the US economy is weather- sensitive,” says Null. So if someone could really know what they weather was going to be like 90 days out, think how much money they could make in commodity futures. That would make you the richest guy on the planet.”

The past few years offer a textbook example of how El Niños and La Niñas often turn out to be the opposite of what’s “typical.”

Take the past few years: Null points out that last winter was a LaNiña year, albeit a mild one. So did we get a nice dry winter six months ago? No, we got pounded by record-breaking rainfall day after day, week after week, until our reservoirs were literally spilling over the rim. And what about the winter of 2015-16, when we had a very strong El Niño? Tons of rain? Hardly. That was back in our drought days.

Why are we so weak in the weather-prediction department? Null says it’s partly due to the fact that the part of the Pacific where meteorologists monitor wa- ter- surface temperatures are just that: only a part. And there are many other parts of the ocean where weather-producing stuff is going on, like differing temperature patterns and barometric pressure. And those factors, which are constantly in flux, can conspire to dramatically change the way the actual “weather” looks when it finally comes ashore. Yes, the part of the Pacific where El and La are conceived does shift where the jet stream flows, helping to determine the paths that winter storms eventually take.

But there are a ton of other factors in play.

The 2015 prediction of an El Niño bringing rains to California raised hopes of ending our drought. In the spring of that year, the NOAA said there was an 80-percent probability that El Niño conditions would last until the end of 2015. And as it turned out, the northernmost part of California did get more rain than typical. But the Bay Area saw normal flows while Southern California got less than normal. Looking back, sixteen winters between 1951 and 2015 experienced an El Niño. But six of those years saw below-average rainfall, while five had average rainfall and five had above-average rain- fall. So much for typical. The winter of 2016—17 turned out to be the wettest on record in Northern California, breaking the previous record set in 1982—83.

Like many climate experts, frustrated by the failure of a predicted El Niño to bust California out of its drought, NOAA’s Halpert on Thursday was befuddled. During the press conference, he said that while a mild La Niña was on its way, it’s impossible at this point to know how that will translate on the ground. It will probably mean the winter in Southern California will be drier than normal, he said. When asked whether Northern California could see a repeat of the intense showers it saw last winter, Halbert was cautiously optimistic.

“I wouldn’t expect a second year of such extreme precipitation,” he said. Then again, referring to the less-normal-more conundrum, Halpert was clear about one thing: “We’ll see an equal chance for any of those three outcomes for the northern part of California.

“Will we see what we saw last year?” he said. “There’s a very rare chance . . . but not a zero chance.”