Man, that is a great looking thunderstorm cell. I don’t know if it’s a legit “supercell”, but it’s pretty. Is there any updraft at all? I’m assuming not. The docs are pretty dismal. It refers to “Intensity” and “Fierceness” with unhelpful descriptions of the units that don’t actually talk about what that means.
This find is really insightful too though. They referred to “supercells” in the Weather feature discovery video last year, and this must have been it.