You call upon the power of the sky to unleash a devastating attack upon your enemies. You choose a point within range, and a massive bolt of lightning strikes it, creating a 20-foot radius explosion of thunderous energy.   Each creature within the radius must make a Constitution saving throw, taking 10d6 thunder damage and being knocked prone on a failed save, or half as much damage on a successful one. In addition, the explosion creates a powerful gust of wind that pushes all creatures within the radius 10 feet away from the point of impact.