New atmospheric river set to hit Northern California on Monday

An inbound atmospheric river is expected to dump several inches of rain on Northern California beginning Monday, but how much the storm will impact the North Bay wasn’t yet clear, National Weather Service officials said Saturday.

One computer model indicated the strongest rainfall will hit Sonoma, Napa and Marin counties, beginning Monday and lasting until Tuesday night, meteorologist Duane Dykema said.

If that model is correct, the region could see anywhere from a couple of inches to more than a half-foot of rainfall in the most heavily impacted areas, he said.

But a second model on Saturday afternoon indicated the heaviest rainfall will come to the north, in Mendocino County, Dykema said. In that event, Sonoma County and other parts of the Bay Area will likely see smaller rain totals.

“It’s going impact the North Bay almost certainly, but the degree of that rainfall is where the uncertainly falls,” Dykema said. He said the forecasters were hoping for a better consensus on the coming storm before Monday.

Authorities were planning to keep a close eye on local waterways, where levels rose sharply amid the heavy storm that exited the region a week ago. The wettest spot in the Bay Area, Venado, in the hills west of Healdsburg, received more than a foot of rain in that prolonged storm.

It pushed the Russian River 4 feet above its banks in Guerneville and forced the closure of dozens of flooded roads, including a stretch of westbound Highway 37, which reopened on Wednesday.

You can reach Staff Writer Nashelly Chavez at 707-521-5203 or nashelly.chavez@pressdemocrat.com. On Twitter @nashellytweets.