Forecasters predict biggest North Bay rain storm since 2012

Folks who have left their slickers and umbrellas tucked away during the first light rains of the season might want to finally dust them off in preparation for several rounds of rain expected to blow into the North Bay starting Friday night.

As much as 5-7 inches could fall between then and when the last wave passes on Tuesday or Wednesday, said forecasters with the National Weather Service. That would make it one of the biggest storms to hit the North Bay over the past couple drought-stricken years.

The last time the Santa Rosa area saw that much rain was during a 2012 storm that lasted from Nov. 28 through Dec. 2, forecaster Steve Anderson said. A little over 7.5 inches fell then.

This weekend, the first wave is expected to arrive sometime Friday evening and bring 1-2 inches to much of Sonoma County by Saturday morning, forecaster Diana Henderson said. More could fall in the coastal hills.

Intermittent rain will likely persist throughout Saturday, with the second round of heavy rain arriving early Sunday morning. That system, lasting through Sunday, could dump up to another inch of rain in most areas of Sonoma County, she said.

More rain is likely to fall Monday through Wednesday, Henderson added.

“It’s generally going to be wet, rainy and wet through Tuesday or so,” she said.

It’s expected to be enough to potentially cause some minor flooding and downed trees, prompting the National Weather Service to issue a hazardous weather outlook for the next week.

While major rivers are unlikely to flood, the rain will probably flush fallen leaves and debris down streams, causing clogging and surface street flooding in urban areas, Anderson said.

Local public safety agencies said they weren’t taking any extra steps to prepare for the coming rains, but planned to monitor creek and stream levels - especially if rains continue for several days.

“It would take a substantial amount of rain to lead to anything major,” said Petaluma Fire Capt. Chad Costa. He said the city always has precautions in place, such as stocking predesignated areas with sandbags. The city also monitors the Petaluma River’s levels, but serious flooding is not expected given current low water levels.

And while it would take “many more” similar rains throughout the year to end the drought, the expected storms will help shrink the area’s water deficit, Anderson said.

As of Thursday, Santa Rosa had received just 2.2 inches of rain since July 1. That’s better than last year’s dismal total of 1.6 inches for the same time, but still under the city’s 6.4-inch average for the period, Anderson said.

Temperatures are expected to stay mild, with lows around 50 and highs near 60 degrees.

CHP Sgt. Allan Capurro said officers will be out in force this weekend to monitor holiday traffic and urged people to be cautious on the road.

“Obviously, the pending storm is going to play a big factor in addition to the increased traffic,” he said. “People need to slow down and allow the time they need to get from spot to spot.”

Staff Writer Jamie Hansen blogs about education at extracredit.blogs.pressdemocrat.com. You can reach her at 521-5205 or jamie.hansen@pressdemocrat.com. On Twitter @jamiehansen.