There is currently an upper level low pressure system spinning just off the coast. There is cold unstable air associated with this low and the region being in the base of an upper level trough. These features can become active when daytime heating causes rising air from the surface triggering convection. Showers and some isolated thunderstorms are probable today at higher elevations and in the interior, otherwise just partly cloudy skies for most of the coast.
Wednesday and Thursday have isolated shower potential as some unstable air lingers over the region, but activity should be very limited. I think most stay dry.
It is complicated but the current system basically splits in two, but both parts look to exit Friday. The quiet weather lasts thru Saturday but Sunday-Wednesday an upper-level low will drop southward from the Gulf of Alaska on Friday and Saturday, then start to push eastward into Southwest California on Sunday.
Models have differing views of how this all works out but agree on the basics that it looks wet to begin next week. My ballpark of 1-3" is just my current outlook, considering the differing views please chack back for updates regularly about this part of the forecast. This is because it currently appears that the trough allows cold air to spill in and low pressure to spin around the base of the trough for a couple days.
If we want to go even further it looks like the following weekend could see yet another rainy period. Again all in the rather speculative long term part of the forecast but the climate prediction center likes it to be generally cool and wet over the 8-14 day period.