After a dry week marked by red flag warnings signaling fire danger and the threat of power shutoffs for some, rain was forecast to shower the Bay Area on and off through the end of the week.
Showers were falling by sunrise Monday in the East Bay, with rain spreading to the South Bay by mid-morning. The wet weather had tapered off by Monday afternoon, leading to clear skies and sunny, albeit cool conditions.
National Weather Service meteorologist Roger Gass forecast a break in the rain today before chances of rain increased again on Wednesday — with a 100% chance of showers across the North Bay and up to a 70% possibility in San Francisco — before the rain would subside again by Friday.
About three-fourths of an inch was expected to fall over the North Bay coastal areas on Monday, while the North Bay valley areas might see up to half an inch in precipitation. Both the South Bay and East Bay regions were expected to receive less than one-third of an inch in rainfall on Monday, Gass said.
A segment of westbound Ashby Avenue at Seventh Street was shut down around 10:55 a.m. Monday due to flooding at the underpass, according to the Berkeley Police Department. The underpass was reopened again in mid-afternoon.
The heaviest rains later in the week were also expected to hit the North Bay, with higher elevations set to receive another three-fourths of an inch of rain, with about one-third of an inch of rain forecast around Santa Rosa and over San Francisco. The South Bay and East Bay might receive less; Gass said less than 0.15 of an inch of precipitation could fall over those areas during the week.
Temperatures in the Bay Area are expected to be generally in the low to mid-60s throughout the week, but San Francisco was expected to reach the upper-50s, according to Gass. Humidity was forecast to be high, but fire weather and winds were not expected to be much of a concern, he said.
The cause of this “unsettled pattern” of rain is several troughs of low pressure moving through the region, Gass said, with potential for widespread precipitation in the Pacific Northwest and Northern California. The weather pattern is characterized by cooler conditions and slightly above average precipitation, but no ridge of high pressure, Gass said.