03 Galant driver side rear window leak

[sglane]

Notice an air leak and noise from it when going over 55 mph. When the window is up all of the way it's the worst and if I just barely tap the power window button just slightly, it's better but still noticeable. There's no problem with rain leaking in but it's a nuisance for anyone sitting in that seat as well as everyone else in the vehicle.

Any ideas?