Hard to tell but are you even sure the marks are in the willow and not the scuff?
I could be completely wrong but I really don't think that is storm damage - as I understand it - storm damage manifests itself as darker bars across the wood - almost in a uniform line - unlike what a shown in the pictures which look almost like sanding marks or grooves of some kind - again I'm no expert but I've had a couple of storm damaged bats that had the marks as the darker uniform bars almost like a line of shadow across the bat, however as I said I could be entirely wrong. Hope you get this sorted if it is storm damage
Tricky one. Some warranties dont pass to the second owner. Contact Rob if you can get the purchase details. If the warranty stands, use it. Might be a great bat that lasts like any other.