Ballad of Thunder

You play a soothing ballad on your instrument that calls forth a vivid storm. When you cast this spell and on subsequent turns using your actions you call forth a bolt of lightning of 100 ft. tall and with a radius of 5 ft. A creature must make a dexterity saving throw or take 1d8 lightning damage, half as much on a success. For every turn after the first one the damage increases by 1d8.
While you are concentrating on the spell, you take control over the storm above you. Spells like Call Lightning and other storm related hazards can no longer be activated as long as you concentrate on the spell. When you use your action to do anything besides maintaining concentration, or if you drop your instrument, you will break concentration and the spell ends.

When you cast this spell using a 5th-level spell slot you increase the starting damage by 1d8 for every two levels above 3rd.