Conjure Thunderstorm

A churning storm cloud forms, centered on a point you can see and spreading to a radius of 360 feet. Lightning flashes in the area, thunder booms, and strong winds roar. Each creature under the cloud (no more than 5,000 feet beneath the cloud) when it appears must make a Constitution saving throw. A creature takes 2d8 thunder damage and is deafened for 1 minute on a failed save, or half as much damage and isn't deafened on a successful one. A creature deafened by this spell makes another Constitution saving throw at the end of each of its turns. On a successful save, the creature is no longer deafened.

When you cast the spell, six bolts of lightning flash down from the cloud to strike six points of your choice that you can see beneath the cloud. Each creature within 5 feet of a point you choose must make a Dexterity saving throw. A creature takes 10d6 lightning damage and is paralyzed for 1 round on a failed save, or half as much damage and isn't paralyzed on a successful one. A creature in the area of more than one bolt of lightning is affected only once. The lightning ignites flammable objects in the area that aren't being worn or carried. On each of your turns until the spell ends, you can use your action to call down lightning in this way again, targeting the same six points or six different ones.

If you are outdoors in stormy conditions when you cast this spell, the spell gives you control over the existing storm instead of creating a new one. Under such conditions, the damage of each bolt of lightning increases by 2d6.