Sounds a bit like Percival Lowell spotting "canals" on Mars, this not being found by subsequent telescopic observers, and yet there are canal-like natural features on Mars. Perhaps he saw them under particularly auspicious angles of sunlight. If the current observations don't match the canal maps he made, then he was talking Baltimores. But if they do, he was (observationally) effing brilliant. I wonder if an observer of Earth, when the sun was shining bright on Sydney, could see the shadow of the Andes as a kind of canal.
Another one is Immanuel Velikovsky's prediction that Venus would be found to rotate in a retrograde manner. Again, that turned out to be true, and surprising. Doesn't mean we have to accept Velikovsky's far out theory as to how that came about. But hey, maybe a tiny quantum of sci street cred.
I'm posting this because I'm not convinced that the downvote mechanism is working properly at El Reg. Discovery awaits.
As to the red spot itself, both images we've seen look stonily like Artist Concepts. If "I could have done that", then some artist probably has, retrospectively saving NASA many meeellion$. <joke icon/> In the second image, I get the feeling that the top of the red is lower in the Jovian atmosphere than the top of the surrounding white clouds. That should be testable, by more than one means but certainly by bouncing signals and seeing how long they take to come back. In which case an alternative explanation could be "red spots, meh, they aren't unusual; what is unique is that the cloud cover above it has dispersed".
See how thoroughly I want to test downvoteology? You know you want it.