Hmmm...I'd almost rather see a supernatural ability for creating storms, along the lines of "Clouds are pulled together by its wingbeats, the sound of thunder made by its wings clapping".
I can see most of those except summon nature's ally, as I get more of a "I stand alone" vibe for this guy.
Just brainstorming here, but maybe would could pilfer some things from the storm elementals...
Thunder and Lightning (Su): Once per minute as a full-round action, a storm elemental can emit a blast of thunder coupled with a bolt of lightning. The thunder deals sonic damage (see chart) to all creatures within 60 feet of the storm elemental. A Fortitude save halves this damage. The lightning is a 120-foot-long line that deals electricity damage (see table). A Reflex save halves this damage. The save DCs are Constitution-based.
Electrical and Sonic Healing (Ex): Storm elementals take no damage from electricity and sonic attacks. Instead, any electricity attack (such as shocking grasp or lightning bolt) or sonic attack (such as sound burst) used against a storm elemental heals 1 point of damage for every 3 points of damage the attack would otherwise deal. The storm elemental can't heal hit points by attacking itself.