Originally I was going to give him a power to manipulate water and call it hydrokenesis or Tsunami but thought it was a bit cliche. I decided to give him something storm related and since he's a category 5, I wanted to give a power that kinda reflects that. So whats the most powerful storm? Hurricanes.
But since he's young he isn't able to use his ability well and is not able to use it for very long at full strength.