Bay Area Storm Season Sneaks In With Sprinkles and a Chance of Thunder

Early-season storms will bring scattered showers and a slight chance of thunderstorms across the Bay Area starting Monday.

The first storm, driven by a low-pressure system off the Pacific Northwest, is expected to mainly affect the North Bay. As much as a quarter-inch of rain could fall in the northern portion of Sonoma County, said Joe Merchant, a meteorologist with the National Weather Service’s Bay Area office. The rest of the Bay Area could receive as much as a tenth of an inch of rain.

“The storm loses a little bit of a punch as it comes onshore,” Merchant said. “We’re not expecting much in the way of impacts as far as any flooding.”

After a break on Tuesday, a second cold front could bring more unsettled weather, with rain forecast for Wednesday and Thursday. Merchant said the highest rainfall totals will once again be over the North Bay, with a 10% chance of thunderstorms.

“Wednesday’s storm still has a chance to sort of overachieve because it’s tapping into some moisture way out west,” he said.

After the storms break, rainfall totals for the week could be as high as an inch in the North Bay and about half as much for the rest of the region, Merchant said.

“By Thursday, most of the interesting weather will be behind us, but the details of the more subtle pattern become uncertain,” meteorologists wrote in the weather service’s daily forecast discussion. They said there “isn’t any real threat of more rain” and conditions will likely be cooler through Saturday.

After this week’s stormy weather, Merchant said long-term weather outlooks suggest warmer and near-normal weather in the coming weeks.

“After these fronts, we’re going to dry out and there’s not much on the horizon after that,” Merchant said. “That can obviously change very quickly.”