The big weather maker is a cutoff low. As the name implies the low pressure is cutoff from the jet stream which usually scoots weather systems thru the region, in this case without strong steering the upper level feature spins away for days on end.
The low happens to be spinning right over the Central Coast so rainfall which originated to the south and east are wrapping around the circulation and being drawn into the area. This will continue thru later Thursday.
I think Friday we'll be dry and we'll start to warm thru the weekend.
Not only will we see additional rainfall, for some there is even potential for up to 1" additional rain. Snow levels are around 4000ft, above which several inches of new snow could still fall. Acirss other parts of California with higher peaks the snow potential is significantly greater.
Highs in the 50s and low 60s today should be reppeated Thursday before 70s return for many over the weekend into early next week. At the coast a more typical spring marine layer should re-form next week
