Hey Slinky! Currently the clouds in the lightning effect are simply a sprite being spawned within the particle system. You can easily turn those emitters off if you so choose. That being said, while I will be releasing a new updated to the weather fx pack soon that contains a lightning blueprint that spawns a dynamic spot light that casts good shadows from the source of the bolt, even this would not reach your skydome, which is where the clouds live in the ultra dynamic sky. What I would recommend, is to replace the texture for my clouds in the lightning clouds material with a cloud texture that is similar to the one he uses in the UDS package, that way it should blend nicely.