So I imaged Jupiter on UTC 2021-09-15 from 1h29m to 2h30m. After processing the images today, I noticed a spot on the deep brown equatorial band on the northern hemisphere, as shown with arrows in the image below. It rotates with the Jupiter, so I don't think it is an artifact. The thing is, there was no such a spot at a week ago, as shown also in the image for comparison. It looks like that the spot newly appeared. Imagines were done with Meade 8", 2X Barlow, ZWO ADC.
I have imaged Jupiter only for a couple of nights since mid August, so my experience is very limited. I would like to ask more experienced planet imagers if this kind of appearance of a feature common for Jupiter. After all, we are looking at the atmosphere. If so, what would this spot be? Perhaps someone has a clearer image of Jupiter at roughly the same time?