Atmospheric rivers enter California's forecast – SFGATE

Atmospheric rivers enter California’s forecast  SFGATE

Chances of heavy precipitation in California have entered next week’s forecast. Atmospheric river activity could bring rain, snow and high winds for roughly the period of Nov. 13-17 to parts of California and the Pacific Northwest, according to the Climate Prediction Center. In California, the greatest risk of significant precipitation is in the north, though it’s too early for forecasters to know exactly where the atmospheric rivers will land. “We know there’s going to be above-average atmospheric river activity over the U.S. West Coast next week, but we’ll hone in on where that will happen as it gets closer to the event,” Deanna Nash, a precipitation and geohazard scientist for the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography, told SFGATE.

“The signal for those high anomalies is the highest over Washington and Oregon, but other models are showing higher anomalies from Oregon to Northern California.” An atmospheric river is a long region in the sky carrying water vapor from the tropics. Atmospheric river activity will lead to a 40% to 60% risk of heavy precipitation across regions in the Pacific Northwest and Northern and Central California from Nov. 13 to Nov. 15, according to the Climate Prediction Center’s Nov. 5 memo. This includes chances of heavy snow in the higher elevations of