Mo was ready to try the spell out on his cloud. Sort of. He really DID wish that he could keep it fluffy and white and happy looking, but that was sort of not the point, right? He eyed up the cloud briefly before opting to just DO it already, and Mo made the circular motion with his wand.

"Stiricidium Nubila," he spoke clearly, and continued to crank his wand in a circle as that little white cloud grew and darkened and flattened and became increasingly ominous. Merlin, what if it turned into a thunderstorm instead of a snowstorm? Were his shoes rubber-souled?

He paused to check his shoes, and the lack of wand motion with the spoken incantation caused his growing dark cloud to deflate and de-darken. At least he had his fluffy white cloud again, right? Merlin... time to start over.