Prospects of rain in Marin forecast

Marin County could get about half an inch of rain from a system expected to arrive in the Bay Area late Sunday night, according to the National Weather Service.

The rain is expected to linger into Tuesday, the agency said. Much of the North Bay is expected to receive 0.10 to 0.50 inches, while the northern part of Sonoma County could get 0.5 to 0.75 inches.

San Francisco may get one-tenth of an inch. Farther south, there will be significantly less rain.

“It looks like any really measurable rain is going to be north of the Golden Gate,” said Jan Null, a meteorologist with Golden Gate Weather Services in San Mateo County. “There will be drizzle in Half Moon Bay and some other parts of the Bay Area.”

It's been four months since the Bay Area received any significant rain. May 3 was the last time, when 0.54 inches fell in San Francisco.

The storm will shift Northern California's weather from a summer pattern into more of a fall and winter feel.

The rain will bring major benefits, experts say. It is expected to help firefighters who are battling several lightning-started wildfires in rural forests near the Oregon border — including the 96,000-acre Six Rivers Complex Fire, which is burning in Del Norte County and was 79% contained Friday, and the 30,000-acre SRF Complex Fire, which is only 7% contained, and burning in Humboldt and Del Norte counties.

All that rain will slow the fires substantially, but also will douse their smoke — much of which has drifted into the Bay Area this week — and blow it west and north, experts say.

“It may not fully extinguish these fires,” said Daniel Swain, a climate scientist at UCLA. “A lot of the fires burning up there right now are in heavy heavy timber. But it really will dramatically reduce fire activity and if it's followed up by another rain event that might really be the end of first season up there.”

For the Bay Area and other locations downwind, “it's going to dramatically improve air quality,” Swain added.

As of Monday, 257,405 acres had burned in 2023 in California on lands overseen by Cal Fire, the state's leading firefighting agency, and the U.S. Forest Service. That is just 22% of the fiveyear average over the same dates.

“It's rather nice to be in a window where there where there aren't ongoing concurrent fire crises in multiple parts of the state,” Swain said.