[Billg64]

Please correct me if I’m wrong; but isn’t the entire surface we see nothing more than gasses above the surface. If that is the case, than the spot is nothing more than a clearing in the clouds

[LibWhacker]

No, you're right about that. There's no solid surface on Jupiter, only cloud tops (which is what they mean when they talk about the "surface of Jupiter").

When Shoemaker-Levy hit the planet, the impact sites were dark because of dark material the comet itself delivered to Jupiter and because of darker material the impact churned up deeper down in the atmosphere. Comet fragments would penetrate some distance into the atmosphere, explode, then plumes of this dark debris shot out a couple of thousand miles before collapsing back onto the surface. I'm guessing it's the same here, if this is an impact.