California drought worries rise as La Niña reemerges in forecast

As the days darken, all eyes are on the Sierra Nevada, then the sky, with a glance back at the mountains, to the Internet for forecast information, over to the thermometer — all in a fidgety search for a sign, any sign, that this winter will be wet.

It is an increasingly desperate and often futile exercise that farmers, skiers, water officials, meteorologists and residents tired of water rationing slog through each fall in an attempt to decrypt the capricious California climate.

Still, the National Oceanic and Atmospheric Administration took an educated crack at it Thursday with its annual winter weather outlook, predicting that a “weak” La Niña pattern is likely to influence conditions across the U.S. starting in late fall or early winter.

The La Niña could cause drier than usual skies in the Golden State. That could mean a continuation of the state’s five-year drought, with no recovery in sight.

“The outlook is for above-average temperatures over the entire state,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “Heading into the winter, likely the biggest concern is drought.”

Halpert was quick to point out that La Niña is fickle and that the outlook — which has already changed twice this year — could shift again. The condition appeared in the spring over the equatorial Pacific, then disappeared over the summer, forcing climate scientists to dial back their forecast in September, before re-emerging this month.

The gloomy forecast is hard for snow lovers to believe, especially after the Sierra got a decent dusting during last weekend’s storm — with more on the way.

Daphne Stumpel walks on the beach with her dog Gigi at Crissy Field in San Francisco, Calif. on Thursday, Oct. 20, 2016. Forecasters are predicting that La Ni�a conditions may lead to another winter of drier than normal weather. less Daphne Stumpel walks on the beach with her dog Gigi at Crissy Field in San Francisco, Calif. on Thursday, Oct. 20, 2016. Forecasters are predicting that La Ni�a conditions may lead to another winter of drier ... more Photo: Paul Chinn, The Chronicle Buy photo Photo: Paul Chinn, The Chronicle Image 1 of / 12 Caption Close California drought worries rise as La Niña reemerges in forecast 1 / 12 Back to Gallery

With 1.18 inches of rain since Oct. 1, San Francisco already has seen twice the amount of precipitation it normally gets by this time of the month. Another storm is expected Monday and Tuesday, according to the National Weather Service.

Some ski resorts in the Lake Tahoe area are talking about opening as early as Halloween — depending on the forecast. Skiers and boarders and those in the industry are watching closely.

“It’s a big, big deal,” said Greg Whitehouse, owner of California Ski Co. in Berkeley, who reported brisk sales so far. “We’re absolutely snow farmers. We look at the prognosticators, of which there are many, from NOAA to the Farmers’ Almanac, until I find one that I like, and then I hold onto it and hope it is true.”

The La Niña weather pattern is characterized by a cooling of surface water in the equatorial Pacific. It generally favors drier, warmer winters in the southern United States and wetter, cooler conditions in the northern part of the country.

In California it has, in the past, meant less precipitation, but Halpert said there are too many variables to make a definitive prediction.

Storms are likely to hit the northern part of the state this winter, he said, but are less likely in the south. It is an open question whether the storm track reaches the central part of the state, which includes Lake Tahoe and San Francisco.

“The farther south you go, the odds of below-normal precipitation go up, and San Francisco is right in middle,” said David Miskus, an NOAA drought expert. The outlook for Central California also “depends on whether the precipitation falls as rain or snow.”

NOAA forecasters have pegged the odds of La Niña persisting through the winter at 70 percent.

The uncertainty annoys Arturo Beyeler, the owner of San Francisco’s Mountain West ski shop. He said all the meteorological gobbledygook confuses skiers and boarders, who have been known to write off a season — meaning no rentals or purchases at his shop — based on unreliable forecasts.

“It’s frustrating when they keep making new adjustments,” Beyeler said. “The jargon of weak El Niño or La Niña — people don’t even know the difference, but word gets out there and if it’s negative, it spreads. Winter is just winter the last time I checked.”

While the drought is expected to persist in Southern California, a partial recovery could happen in Northern California if enough rain and snow fall — but it could go either way, the forecasters said.

“El Niño is always good, and last year it was so good we had a banner in front of the store that said ‘El Niño for President,’” Whitehouse said. “This year we have a banner that says, ‘Fall Sale.’ If it snows hard enough, I will get a sign made for La Niña.”

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite