A sudden ball of lightning explodes from a point of your choice within range. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A creature takes 4d6 thunder damage and 4d6 lightning damage on a failed save, or half as much damage on a successful one. Every creature within 500 feet of the explosion can easily see and hear it.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the lightning damage increases by 1d6 for each slot level above 3rd.