Wet grounds and damp air were back in the Bay Area late Wednesday and into Thursday, signaling the end to a lengthy stretch of dry weather and the onset of rainy weather that the National Weather Service said is on tap into next week.
The rain began to fall again Wednesday — light but steadily and slightly ahead of schedule — as a small low-pressure disturbance began to take apart the dry, smoggy air created by mostly uninterrupted high pressure for more than a week. The weather service said that rain mostly was out of the region by 6 a.m., having moved to areas of the Central Coast. Save for the chance of a few sporadic, short-and-light showers, Thursday is expected to be dry.
“The next rain is probably going to be Friday,” NWS meteorologist Crystal Oudit said. “More so, Friday going into Saturday. That will be a heavier band than we just had.”
The initial band dropped about eight-tenths of an inch of rain in areas of Oakland, Richmond and Orinda; four-tenths of an inch in San Jose and about .15 inches in Concord.
The biggest rainfall totals were in in the North Bay and Santa Cruz Mountains. Almost an inch of rain fell in Santa Rosa — an area drenched by an atmospheric river storm last month — and an inch fell in Ben Lomond.
The first system also seemed to clean up the air. The Bay Area Air Quality Management District forecast moderate air quality throughout the region, a bit better from previous days when some areas had air that was unhealthy for those with respiratory and other conditions.
Now comes the wait for the next band of moisture, which Oudit said is coming from the Gulf of Alaska. With it will come higher rainfall totals, high surf and king tides, making it a particularly harsh system for Bay Area residents along the coast.
The weather service issued a high surf advisory beginning at 1 p.m. Thursday and lasting through 4 a.m. Friday for all beaches along the Pacific Coast except Santa Cruz. Waves are expected to break between 18 and 22 feet, and swimming and surfing conditions will be dangerous.
In addition, the weather service put Marin, Sonoma, and Napa counties under a flood watch from 2 p.m. Friday until 4 p.m. Saturday.
Increasingly powerful winds also will build into the weekend, according to the weather service. They are expected to hit their peak on Friday night and Saturday with southerly winds blowing 30 to 40 mph regularly and gusting at more than 50 mph in the coastal areas of the Bay Area, Central Coast, Santa Cruz and Santa Lucia Mountains.
The weather service issued a high wind watch for those areas from 7 p.m. Friday until 7 a.m. Saturday.
In the Sierra Nevada, about 4-to-8 inches of snow was expected to fall at Echo Summit and about 1-4 inches were expected in South Lake Tahoe.
Once that system is finished doing its thing, Oudit said the weather will “ease up a little bit” on Sunday before another band of rainfall hits the area on Monday. That rain storm is not expected to be as strong as the one that starts Friday
“But it will probably be stronger than the one that just came through,” Oudit said.
In all, Oudit said the East Bay and South Bay areas of the region likely will pick up between 2 and 2½ inches of rain between the three systems.