Series of storms to drench North Bay into second week of January

High, wispy clouds moving inland from the Pacific Ocean Friday were the first visible signs of a series of storms expected to bring on-and-off rain over the next week to Sonoma County and the North Bay.

Strong, gusting winds are expected to arrive before dawn Saturday, prompting a wind advisory from 4 a.m. to 4 p.m. with winds predicted between 20 to 30 mph and gusts of 45 mph in lowlands, reaching 60 mph on ridge tops.

The rainstorms are forecast to drop 2 to ?4 inches of rain in Santa Rosa and surrounding lowland areas by Thursday, followed by scattered showers through the end of the week, according to the National Weather Service.

“It’s just about time for a gully washer to hit us, and if it does come we’re ready for it,” Monte Rio Fire Chief Steve Baxman said. “We spent this morning making sure the chainsaws are sharp and full of fuel.”

The saws could come in handy should the storm topple trees across the region, especially in higher elevations where rainfall is heaviest and in the burn scar areas of the wildfires that hit the region in October 2017.

Santa Rosa Assistant Fire Marshal Paul Lowenthal urged people to clear gutters and storm drains, prepare for the possibility of power outages and to report any dangerous conditions such as roadway flooding or debris slides.

“Within the burn area, we have the potential for sediment runoff from construction sites,” Lowenthal said.

At Lake Mendocino, engineers will for the first time adjust water storage levels based on the weather forecast as part of a new pilot program aimed at increasing available water at the end of the rainy season, Sonoma County Water Agency officials said.

The new program involves releasing some water ahead of a storm, and when dry skies return they will retain what was gained even if it goes above flood levels until the forecast predicts the next coming storm, said Marty Ralph, director of the Center for Western Weather and Water Extremes at UC San Diego’s Scrips Institution of Oceanography.

Ralph, who worked with the Sonoma County Water Agency and the Army Corps of Engineers to develop the program, said the first of the atmospheric river to arrive Saturday was expected to be the strongest and will soak the watershed, allowing subsequent storms to replenish Lake Mendocino and Lake Sonoma, the larger of the two reservoirs.

“The wet spots in the mountains will get more than 6 inches of rain on average over a 10-day period. That’s quite a lot,” Ralph said.

The last measurable rain fell Dec. 24 and brought the season’s total to 9.65 inches at a rain gauge at the Sonoma County Charles M. Schulz Airport, meteorologist Roger Gass said. That is about 66 percent of normal rainfall, which is 14.7 inches for this time of year.

Gass said Sonoma County residents can expect a very “active” series of storms through the weekend.

But the front will actually raise daytime low temperatures, which since Wednesday have dipped below freezing in some parts of Sonoma County. Gass said temperatures will hit the low 40s and rise throughout the day into the mid-50s.

The first storm is expected to begin sometime about midnight Friday or before dawn Saturday and continue through Sunday, followed by another storm system Monday through Tuesday, with another on its heels.

“This system will help add to our storm totals this year with the North Bay picking up most of the rainfall,” Gass said.

You can reach Staff Writer Julie Johnson at 707-521-5220 or julie.johnson@pressdemocrat.com. On Twitter @jjpressdem.