‘Few rounds of rain’ coming to SF Bay Area

The San Francisco Bay Area is expected to see a “few rounds of rain” in coming days, the National Weather Service said. 

The first round of rain is forecast to start Saturday night across the North Bay, “spreading south” of the Golden Gate and into the greater Bay Area into Sunday.

A second round of precipitation is expected to sweep the area “late Sunday night into Monday,” with scattered showers lingering into Tuesday. 

“It’s mainly going to be a light rain, maybe briefly moderate at times,” said Rick Canepa, a forecaster with the weather service. “Southwest- and west-facing hills could maybe see some moderate rain.”

From Saturday to Tuesday, the coastal mountains of the North Bay could pick up to 0.5 to 1 inch of rain while the inland valleys are likely to see 0.3 to 0.5 inch. Areas south of the Golden Gate including San Francisco, the East Bay and the Peninsula are predicted to record 0.25 to 0.5 inch of rain. The Santa Clara Valley, where the mountains can block the rain, is predicted to only pick up 0.1 to 0.2 inch.

Canepa told SFGATE on Saturday afternoon that the rains are “associated with some tropical moisture that has already arrived across the Pacific Northwest. It’s raining in far Northern California and it’s expected to push south tonight. We’re already started to see some radar echoes over Mendocino County.”

A cold mass of air is poised to push into the Bay Area behind these rains. Overnight lows are forecast to drop into the 30s and 40s Tuesday night into Wednesday morning and Wednesday night into Thursday morning. Patchy frost is possible in the valleys of the North Bay on Wednesday and Thursday mornings, the weather service said.