Patty Murray (D) 37
Dino Rossi (R) 33
Clint Didier (R) 5
Paul Akers (R) 3
While the Washington primary isn't until August 17, Rossi is firmly in second place, making it pretty hard for Didier to overtake him. Didier does have the endorsement of Sarah Palin, but her opinion probably carries less weight in a top-two primary system than in a traditional Republican primary.
Since this is only the second time Washington has used this novel system, that could slightly throw off SurveyUSA’s likely voter model. But, given the size of Murray's and Rossi's leads, any minor effect from that shouldn't change the basic result. It now looks like the general election will feature Murray vs. Rossi in November. I would also caution against reading too much into this primary poll about the results for the general. Using the 2008 election for comparison, the primary voters in Washington are a noticeably smaller and more politically engaged group than the general-election voters.
Note: The top-two primary system mandates that independent or third-party candidates who are not one of the top-two vote getters in the primary can't win a slot on the ballot in the general. The November ballot will have only two choices for voters.