For North Coast residents, 2013 will go down as the year when other people got our rain.

Over what should have been the two rainy seasons, weather patterns have conspired to send our moisture elsewhere, meteorologists say.

As a result, water managers are beginning to worry that the rains might not return this year at all, spelling another nasty dry year. The Sonoma County Water Agency is awaiting word from the state on its request to slash flows from Lake Mendocino into the Russian River, a way of preserving the dwindling supply in the reservoir.

They're also planning an aggressive and unusual winter-time conservation campaign, which should debut to customers next week, urging residents to limit water usage, including cutting out outdoor irrigation and car washing.

"We're trying to add to the tools we have available to us" to save water, Chief Engineer Jay Jasperse said. "Currently we don't have a lot of tools."

At the start 2013, the Jet Stream, the great river of wind in the atmosphere, formed its usual huge wintertime loop, but it started its northbound leg hundreds of miles east of its normal spot in the mid-Pacific, causing the wet weather that usually hits the West Coast on the downside to fall instead far inland, over the Rockies.

Since late October, meanwhile, a stubborn high pressure system has been hugging the coast of the Pacific Northwest, shunting all that lovely moist air that usually blows across the California coast in the fall northward, where it is giving coastal Alaska and British Columbia an unusually wet and cold fall and winter.

"That's the rain we would love to see come down here," said California State Climatologist Michael Anderson.

This weather year — July 1 through June 30, 2014 — is shaping up to be the driest on record across most of the state, including the North Coast, according to many indicators. As of Dec. 29, Santa Rosa Airport had recorded just 2.43 inches of rain since July 1; by this time last year, that figure was 21.81 inches, according the Western Weather Group, a private meteorology group based in Chico.

Since Jan. 1, Santa Rosa has seen just 8.71 inches of rain, according to Press Democrat records, compared to an annual average of 32.22 inches.

As of mid-December, the upper reaches of the Russian River had received significantly less rain this year than either 1976 or 1932, previously the two worst drought years in the past 119 years, according to data from the Ukiah station of the National Climatic Data Center.

The status of the Russian River north of Lake Mendocino is further hampered by the near absence of water at Lake Pillsbury on the Eel River system. For decades, some water from that reservoir has been diverted into the Russian River. Right now, Lake Pillsbury is at less than 13 percent of capacity.

Weather forecaster Accuweather reports that San Francisco has had 3.3 inches of rain, just 16 percent of its normal. Of all cities in California, only San Diego has received even half of its normal rainfall for the year.

In the Russian River watershed, Lake Mendocino near Ukiah is down to 39 percent of capacity, according to the Water Agency. That's a serious situation if the rains don't return, but Jasperse and his staff at the agency are beginning to contemplate the previously unthinkable. What happens if another dry season brings the huge Lake Sonoma northwest of Healdsburg to a critical level?

Lake Sonoma, the mainstay of the region's water supply, is at 70 percent capacity, with about 171,000 acre-feet, or 55.7billion gallons. The region uses more than 5,000 acre feet per month and the agency is required to start rationing water to the cities it supplies when capacity hits 100,000 acre feet.

That means that without more rain or a significant effort to cut down on water usage, Lake Sonoma has only a bit more than a year's worth of storage before managers are forced to impose limits on its customers, which are the cities and towns of southern Sonoma County and northern Marin County.

The growing concern about a continued dry spell is not misplaced, at least in the short term, said National Weather Service Meteorologist Michelle Mead. Over the next seven days or so, about as far out as anyone is willing to predict with certainly, that high pressure system off the coast will keep diverting any moisture-causing weather far off to the north, the way a goal keeper deflects incoming hockey pucks.

"If you think of the ridge of high pressure as a goalie, it keeps California dry and warm," she said.

In the longer term, there might be a little bit of hope. The high pressure system has begun to weaken in recent days, making it possible it might break up or retreat westward into the Pacific, which it did for a few days in early December, giving us the brief cold snap that included a welcome dusting of snow on the mountains, Anderson said.

And conditions can change fairly quickly, he said. This time of year is one of the key moments when long-term weather patterns tend to shift, and climate models are giving roughly even chances of dry, normal, or wet conditions in Northern California over the next three months.

Some climate models had predicted some rain around Jan. 9, he said, but that possibility seems to have slipped away over the last few days.

More tantalizingly, some models suggest that the Pacific may be about to slip into the warm, wet condition known as "El Ni?," after a decade in which the opposite, the cool, dry "La Ni?" pattern has held sway most years.

Should an El Ni? develop, he said, it could spell rain as early as March, though it might not be until next fall that the effects begin to be felt.

Unfortunately, he said, the science of predicting weather that far out is maddeningly primitive, with scientists just beginning to see and understand the titanic air and sea patterns that govern West Coast weather.

"We really don't understand how all those pieces fit together yet," he said.

You can reach Staff Writer Sean Scully at 521-5313 or sean.scully@pressdemocrat.com. On Twitter @BeerCountry.