Actually making a storm wouldn't cause that big a shift, if you did it correctly. The big thing that "weather manipulators" have to worry about is that, most of the time, when you "craete" a storm in one place, what you're really doing is moving moisture from the surrounding areas into one spot, which means it doesn't rain in those places, which domino effects outwards. Likewise if you keep an area storm free, what you're really doing is shunting that moisture elsewhere, creating floods and more domino effect. If your power used what was already in the area, the impact would be minimal.