What do primary totals say about Murray-Rossi Senate race?

As of Wednesday morning, incumbent Democratic Sen. Patty Murray came in first in the top-two primary, with 46 percent. Republican Dino Rossi had 34 percent, while fellow Republicans Clint Didier and Paul Akers took 12 percent and 3 percent, respectively. Less than 50 percent for an incumbent is never a good sign. So is Murray in trouble?