After a couple of days of stagnation, an atmospheric river storm that has brought possibly record rainfall to the North Bay is finally expected to move again on Friday.
The result is likely to be widespread showers all of Friday, and this time, no section of the Bay Area is expected to be spared, according to the National Weather Service.
“Those people who have been watching the North Bay get slammed are going to be the ones who feel it (Friday),” NWS meteorologist Dylan Flynn said early Friday. “This front is gonna start to march south in the later part of the morning, and you’re gonna have rain impacts everywhere.”
In the East Bay, that likely means 1½ inches or rain will fall, and in the South Bay and Peninsula, about 1 to 1½ inches are expected, according to the weather service. Those totals would be significantly higher than those areas saw when the first wave of the storm arrived Wednesday.
As for the North Bay, the rain will be steady and add to the deluge that part of the region already has received, Flynn said.
In Sonoma County, Santa Rosa has been hit particularly hard. The city received more than 7 inches of rain Wednesday and has totaled 9.6 inches over a 48-hour period, Flynn said. Another half-inch of rain — “should happen easily,” he said — would give the city its highest three-day total of rain for any three days on the calendar since records began being kept in 1902, according to the weather service.
The weather service said it will reveal those three-day totals at 5 p.m. Friday.
Flood warnings remained in effect Friday morning in most areas of the North Bay.
“This storm front basically hasn’t moved at all,” Flynn said. “The reason for that is that the atmospheric river is mostly stationary, and what we have was not the direct impact of it. But because that system was so strong as it moved in from the north (near British Columbia), we got the strong effects of it. It’s been anchored by some of the lowest pressure we’ve ever seen in the Pacific Ocean, so there was just no where for it to go.”
That has changed because Flynn said the original atmospheric river system “kind of has spawned a child. A new low-pressure system has formed and that’s going to be the one that pushes the parent system south.”
The expected all-day rain that comes with it also is likely to include harsh southerly winds that are expected to wreak havoc with trees and wires. In the Bay Area, they are expected to blow at least 25 mph and could get as high as 40 mph, according to the weather service.
Closer to Tahoe, they will be even stronger. Winds are expected to gust at up to 125 mph on the ridges through 10 a.m., and are likely to gust higher than 50 mph all day Friday. A wind advisory remained in place until 10 a.m.
Snow is expected to fall at the 8,000-foot elevation and up on Friday before dropping to 5,500 feet by Saturday, according to the weather service. Road travel is expected to require chains and snow tires.
A break from the rain is expected during some of the overnight hours before resuming in a considerably lighter fashion Saturday.
“We finally start to get a break,” Flynn said. “It’s what you’d expect for a normal November shower. It might stop raining in the North Bay.”
If it does, Flynn said it likely will resume Sunday and continue on Monday, as it’s expected to do throughout the Bay Area. Not until Wednesday is there a dry day in the forecast.
