Until 25 years ago summertime eddies off the Golden Gate were uncommon. Since then these counterclockwise air masses have become increasingly common and some summers they are a dominant force in determining the wind distribution in the Bay Area. This increasing eddy pattern is associated with the increasing frequency of the North Pacific High developing a ridge over far Northern California so the AM ocean winds at the Bay Area ocean buoys is more NNW than NW.
But for the most part, these eddies have appeared in June through August. But today, April 18, 2021, we saw a tiny brief eddy just off the Golden Gate. This feature dissipated before dawn but was clearly visible in the IR satellite imagery.