After considering the effects of Prop. 14 I realize it's not as simple as I first thought. Jerry Brown won the district 55%-38%. That should indicate it's Democratic enough to be safe, but not Democratic enough to ensure two Democrats are in the top two and go to the November election against each other. In the primary, the two Democrats would split the 55% of the vote, with the loser getting no more than 27%. Republicans would get 38% of the vote. The Democrats would need more than one Republican in the race splitting the vote, because if one Republican gets 28% of that 38%, it'll be only one Democrat in the November election. The Democrats would need the Republicans to have two or more viable candidates for the top vote getter to get less than that.
No matter how many candidates there are in a primary, 30% should be enough to get a candidate to November. In the primary for the CA-36 special election 8 candidates split 95% of the vote. With 3 Democrats and 5 Republicans in the contest, it only took 21.1% of the vote to make it to the general election.
So the June primary is likely to be very important to Brad Sherman and Howard Berman. The loser will likely finish third.