In California, we don't have tea leaves, but we have surprisingly efficient government technology. This Secretary of State website has a constantly refreshing map of election returns by county--which kicked off a few minutes ago--and it may give an early hint at the winner.
A north-south divide has developed in the last few weeks, with Obama leading solidly in the Bay Area and Clinton commanding Southern California. This isn't completely surprising. At the margins, the SoCal electorate has more of a lunch-pail Democrat flavor: union voters, service-sector workers, middle-class homeowners in the suburbs, Latinos, Democrats worried about immigration, etc. This is Hillary's natural base. In the Bay Area, meanwhile, all the predictable stereotypes kick in: lots of college students, young professionals, wealthy latte liberals--all gravitating toward Obama.
Again, this is only true at the barest margins--the Democratic electorate is complicated--but in a tight race, look at the map. If Obama can pick off one of the big counties down south--San Diego, Orange County, Ventura, Los Angeles, or the inland empire counties of San Bernardino and Riverside--he'll be looking good.
Conversely, if Hillary places well in the East Bay (Contra Costa, Alameda counties), North Bay (Marin, Sonoma, Napa), or down in Silicon Valley (Santa Clara, San Mateo)--let alone San Francisco, where Mike Gravel will make his last stand--she may have wrapped up the state.