[UPDATED] According to the comments at www.universetoday.com, the satellite was the recently launched Japanese ALOS-2 mapping satellite, dumping fuel. A few other reports of other sightings have been noted on a few other forums and youtube.
Last night a bunch of friends of us caravaned from the cloudy Seattle skies to the dark, clear skies of Eastern Washington to watch the Camelopardalids meteor shower. While the event was largely a bust, we did see a number of sporadic meteor streaks. It was a fun evening with friends, though!
At one point in the night, Trent pointed up and asked, "Is that a line in the sky?" And sure enough, there was a very clear linear streak in the sky. At first I wanted to believe it was a lingering plasma trail from a meteor that we had missed, however, it stayed evenly bright and straight. Plasma trails fade quickly and tend to snake over time. My second suspicion was that it may be a jet contrail. The tight formation would mean that the jet's beacon lights would still be visible, but none were to be seen, north or south. Then it got more strange. A bright satellite was tracking directly along the line of the "contrail". Not only that, the entire contrail, was about the width of both hands, fingers out stretched at arms length, was moving along WITH the satellite. I've captured images of satellites venting in the past, but they were more spherical in appearance. This had a completely linear appearance. I've never seen a satellite pass central to a long linear cloud. I managed to get a few photos of the event:
Close up, full resolution:
Animated gif version (note, combined time of both frames is 3 minutes), click to watch
Canon 17-mm F4L at F/5.0 17mm
90 second exposure