As an action, a 18-meters radius storm cloud appears centered on a point you can see within 35 meters directly above you. The spell fails if you can’t see a point in the air where the storm cloud could appear (for example, if you are in a room that can’t accommodate the cloud). The cloud moves to always stay directly above you.
When you cast the spell—and as a bonus action on each of your turns thereafter—you can choose a point you can see within 18 meters. A bolt of lightning flashes down from the cloud to that point. Each creature within 1.5 meters of that point must make a Reflex saving throw.
On a failed save, a creature takes 3d6 lightning damage, is deafened for 1 minute, and it can’t take reactions until the start of its next turn.
On a successful save, it takes half as much damage.
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, each creature within 3 meters of the point must make the saving throw.
You can increase the damage by 2d6 for each additional mana or psi expended.