First storm system set to arrive in San Francisco Bay Area; rainy weekend ahead

Another round of rain is headed for the greater San Francisco Bay Area Friday, arriving in the afternoon and impacting the evening commute to kick off the start of a wet and stormy weekend.

The first storm system is set to arrive Friday afternoon, which will mark the first of two significant periods for rainfall. The greatest amount of precipitation will fall in the North Bay with two to three inches projected in the Cloverdale area and higher rain quantities in the coastal ranges.

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The rain will be heavy enough to have an impact on Bay Area roadways, so drivers should anticipate slower travel times during the evening commute. 

Daytime highs will be mostly in the lower 60s on the coast and inland, and in the upper 50s and 60s around the bay and inland. Overnight lows are expected to be mostly in the 50s, with some areas dropping into the upper 40s.    

Winds will be gusty out of the south early Saturday morning, with gusts in the 25-30 mph range beyond the frontal passage. Later in the day, winds ease as conditions become slightly drier, which could mean the 49ers game against the Packers will not be as wet as some expected, though some scattered showers could persist. Still, Saturday late afternoon into Sunday afternoon appears to be the “driest” part of the weekend.

The second period of heavier rain is projected for Sunday night into Monday morning, with amounts of 2-3.5″ possible in the coastal mountains. Highest elevations and peaks could potentially see up to 4.5″ of precipitation. Lower elevations such as the San Francisco, North, and Monterey Bays are likely to see amounts ranging from 1.5-2″. Further inland and in rain-shadowed regions such as the San Jose area, rain amounts are reduced with 1.25″ expected.

Rain amounts could result in minor flooding of creeks and roadways. Shallow landslides are also possible given increasingly saturated soils heading into early next week.