Atmospheric river to bring up to 4 inches of rain in parts of Northern California this weekend

CRESCENT CITY, CA -- SEPTEMBER 18, 2019: Visitors walk along Lighthouse Way near the Battery Point Lighthouse and Museum, in the background. The 10-year plan for the Crescent City Harbor District, one of few economic engines in rural Del Norte County, is grim. The isolated area has an aging population. It's hard to get there. There's nothing to do. It's threatened by sea level rise. On top of it all, there's the threat of tsunamis, which wiped out the harbor in 2011. Crescent City has tried to make the best of a frustrating situation. (Myung J. Chun / Los Angeles Times)
Visitors walk along Lighthouse Way near the Battery Point Lighthouse and Museum in Crescent City in 2019. Del Norte County could see as much as 3½ inches of rain this weekend. (Myung J. Chun / Los Angeles Times)

A weak atmospheric river is expected to dump as much as 3½ inches of rain in the northernmost parts of California starting Friday, while Sacramento and the lower Bay Area will see light precipitation.

Del Norte County, which is bordered by Oregon and the Pacific Ocean, will likely be the state’s hardest hit area, according to the National Weather Service.

Roughly 1½ to 3½ inches of rain is expected to fall between Friday at 5 a.m. and Saturday at 5 a.m. That’s up from between a half inch and 1¼ inches expected for the previous 24 hours.

“It’s a typical fall season storm system that’s passing through the region,” said Jonathan Garner, a weather service meteorologist based out of Eureka. “It’s not a particularly strong atmospheric river but it may impact complex terrains with periods of moderate to local heavy rainfall.”

The 600-person riverfront town of Gasquet is anticipating 3.43 inches of rain from Friday into Saturday, according to NWS estimates, with Crescent City expected to see 2.72 inches of rain during the same period.

The weather service issued a flash flood watch for the county's interior, which has been rocked by recent fires, from Friday evening until Saturday afternoon. The agency said there is a chance of debris flows.

Read more: Wildfires knocked out power to an entire California county. The unprecedented fight to bring it back

The soil in the region was scarred by the Smith River Complex Fire from early October, which burned around 95,000 aces, and the "messy, slick mud" could mix with rock and downed timber in a debris flow, Garner said.

No evacuations were planned as of Thursday afternoon, according to Garner.

A small craft advisory was issued Thursday as winds gusted from 10 to 20 knots along the coast.

The National Weather Service bureau in Sacramento is advising residents to clear leaves and debris from storm drains along with house gutters. They should also check and replace worn wiper blades, while locating packed-away umbrellas and rain gear.

About 3 to 4 inches of rain is expected to fall in Eureka between Thursday and Tuesday, with risks of "ponding" and longer commutes expected in the northern portions of Humboldt County. About 2 to 3 inches of rain is anticipated in Weaverville and Trinity County, along with Blue Canyon and Placer County.

Read more: Early season atmospheric river to bring 'deluge' of rain to Northern California coast

Larger portions of Butte, Mendocino, Plumas, Shasta, Tehama and Yuba counties are expecting between 1 to 2 inches of rain.

There’s a minor risk of pooling of water on the roads in Sacramento, San Francisco and the general Bay Area, with larger threats further north.

The weather service is calling expected rain near the Bay Area “light,” with as much as a half inch anticipated in San Francisco and Half Moon Bay between Saturday and Tuesday. Around a half-inch of rain is predicted in Sacramento while as much as an inch may land in Cloverdale and Sonoma County.

The snow levels in Northern California are anticipated to reach 9,000 to 10,000 feet in the mountains and will drop to 6,000 to 7,000 feet by the start of the new week.

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This story originally appeared in Los Angeles Times.