I'm actually not confident at all that it'll be this close. Clinton might very well only invest in CA after May 17th, since she really doesn't need any of the other states (and can probably take NJ mostly for granted anyway). Because of how much she'll pour into this state, I wouldn't be surprised if the margin is close to what it was in NY, or maybe OH.
But CA will be his last stand, and the donations will likely reach an unprecedented level due to this. On top of that, Hillary is mostly saving her money for the general at this point. He outspent her something like 10:1 in Wisconsin and 2:1 in New York.
I'm not denying that Sanders will also put up a huge effort, but the votes just might not be there for him to really make it competitive. He'll do well in Northern CA, and SF should be a good city for him, but I don't think that's be anywhere near enough to offset how badly he'll get beaten in SoCal.
