The rainy season has officially started in the Bay Area as a storm is expected to bring nearly a month’s worth of rain to San Francisco in less than 24 hours, according to the National Weather Service.
Dalton Behringer, a meteorologist for the Bay Area weather service office, said most of the forecast precipitation will fall late Monday morning through the evening. In the North Bay, about a half inch of rain is expected during this storm and will arrive mostly between 11 a.m. and 4 p.m. Monday, according to Behringer.
San Francisco is expected to get 0.82 inch of rain, and Behringer said 90% of that precipitation will fall Monday afternoon between 1 and 5 p.m., just in time for the evening commute. Oakland is expected to get around 0.8 inch of rain on Monday, with the heaviest rain falling between 11 a.m. and 5 p.m., although showers are expected overnight into Tuesday.
Further into the East Bay, 0.88 inch is expected near Walnut Creek through Monday evening, with the heaviest totals falling before 5 p.m.
As the rain bands move south, rainfall totals are expected to increase up to 1.5 inches of rain in the Santa Cruz Mountains, with the heaviest showers expected before 11 p.m. Monday.
After the strongest rain passes, there will still be a chance of showers in the Bay Area throughout Tuesday.
“Overnight and tomorrow morning is going to be more like scattered or isolated showers,” Behringer said, with most regions seeing less than a tenth of an inch of additional rain. “A lucky few will get another significant, maybe a quarter inch or so.”
Behringer said since October is a relatively dry time of year, even substantial rainfall likely won’t lead to major flooding. On average, San Francisco gets about 0.94 inch of rain in October, so this storm will deliver nearly the entire month’s worth of precipitation in one go.
“It’s kind of easy to do it because it’s October,” he said. “It’s notable, but not super crazy.”