Thunderstorm Wind in San Francisco County, California

A tornado warning for San Francisco and San Mateo Counties was issued at 5:51 AM after a rotating thunderstorm was observed off the coast of San Francisco. This is the first tornado warning issued on record for the city of San Francisco, using records that extend to at least 2005 and potentially since 1986. After an NWS storm survey that extended from the west side of Golden Gate Park to the Richmond district, it was determined that damage along the path of the cell was consistent with straight line wind gusts around 80 mph.

An intense storm system came through the Bay Area and Central Coast through the night of Friday December 13 into Saturday December 14 as a cold front combined with a developing low pressure system off the California coast, causing numerous weather impacts throughout the region. Among the notable impacts from the system, a confirmed EF1 tornado touched down in Scotts Valley, the first recorded tornado warning in San Francisco received significant public and media attention, strong gusts associated with a squall line caused multiple weather impacts across the region, and most of the city of Monterey and the surrounding cities of Seaside and Marina lost power on Saturday morning and did not get it back until the following Sunday afternoon and evening.