Powerful Atmospheric River Could Slam NorCal Next Week

SAN FRANCISCO — Forecasters are growing more confident that the Golden State will close out January with a powerful atmospheric river that could hammer NorCal with several days of heavy rain and high winds while dumping significant snowfall over the Sierra.

This week, the National Weather Service's Climate Prediction Center shared an early look at the impending weather event, including new outlooks that show growing odds for impactful storms to begin by the latter half of next week.

"We are closely watching what could be a notable pattern shift in late January and early February," the weather service warned. "If this pans out, a period of very wet weather could impact California."

While it is still early in the forecast period, models favor significant rain, snow and wind slamming the West Coast then barrelling inland sometime between Tuesday and Friday, with lingering impacts possible well into the first week of February. The chance for abnormally wet weather is as high as 70 percent for most of California, and snowstorms could wallop the mountains over five days.

Details on the timing and severity of the weather should come into better focus early next week.

"The heavy precipitation can lead to localized flooding and landslides, particularly in regions that have recently received heavy rains," the Climate Prediction Center warned. "At higher elevations, such as the Sierra Nevada, Klamath Mountains, and the Mogollon Rim, heavy snow is expected."

Though the weather is likely to present several hazards, like the barrage of atmospheric rivers California endured early last year, more substantial storms developing could go a long way in making up for an as-of-yet underwhelming El Niño winter.

According to the Los Angeles Times, the Golden State's snowpack water content measured just 55 percent of normal as of Monday, despite recent storms that dumped more than a foot of fresh snow over much of the Sierra. At Mammoth Mountain, the resort logged just 26 inches of snow between October and the end of last year, compared to 177 inches over the same period last winter.

Fortunately, experts are bullish on a much more active finale to the winter, which could help alleviate concerns of a "snow drought" that could worsen fire hazards and hamper the state's water supply. One expert recently told Patch that California may still end up with an above-average year of precipitation, and the incoming atmospheric river could be a preview of things to come.

"There's a lot of rain in the forecast for now," said Paul Ullrich, professor of regional climate modeling at UC Davis. "There's this stationary weather pattern off the coast of California that directs the storm track and tells us how many atmospheric rivers we're going to get. That stationary weather pattern is conducive for wetter conditions for the remainder of the winter season."