Three sources...

Weather Underground gives hour by hour temperature, wind, and precipitation in table form (not just "chance of rain" for the day which is useless), and a rain forecast. It's not always perfect, but you can watch the radar too. Monday I rode home on wet roads, but the forecast was right enough that it wasn't raining enough to change clothes. Weather Underground is also notable for having automated crowdsourcing, anyone can hook up their little weather station to the network, and they have a lot of widgets on their page asking if their forecast is correct.

The second is the Facebook page of NWS Sacramento who do a pretty good job telling the story of the weather

The third is this Tahoe ski blog, which does a good job talking about storms coming in during the wet season, and the climate for the water year. Not intended for a Sacramento rain storm forecast but it amounts to one nevertheless.
https://opensnow.com/dailysnow/tahoe