These formations are regular at this time of evening spreading, as the sun sets, from much larger cumulus formations. Off camera to the east was a steady stream of violet stratocumulus, exemplary of coming sprinkles.
Downwind from a mountain range are commonly found, flat, oval cloud formations known as lenticular clouds. These clouds usually stay in one place as winds gust through them. The separation of stratocumulus clouds from the western lenticulars were, likely, signs of the off and on sprinkles we were to experience throughout the day today, in San Jose. Pictured below are lenticular clouds I caught, just as the sun was going down, stationed over the western range.
This next photo is likely another stratocumulus, however this cloud might be cumulus fractus. The coloring of this cloud was a sure sign that the weather man had this weekend forecast correct when I checked last Wednesday.
The shape of the cloud reflects the way winds, racing over the western mountains, meeting with differing pressure as they sweep over the valley, lift the cloud and develop it vertically.