You cannot cast this spell if there is not at least 100 ft. of space above your head. The clouds you create follow you, and lightning always strikes your target from the clouds directly above them.

Dexterity Save

• Failure: Target takes 3d10 electric damage.* If you cast this spell in stormy weather, the damage increases by 1d10.

• Success: Half damage.

• Concentration: Once on each subsequent turn, you can call down lightning again as a action.

*Upcasting: Increase damage by 1d10 lightning for each spell level above 3rd.

When you cast this spell, you create a cylindrical stormcloud that is 10 ft. tall with a 120 ft. radius directly above your head at least 100 ft. above the ground, which does heavily obscure its area. Because the lightning comes from above your targets, the target can only have cover from the lightning if they have cover above their head. If you move into a building, the cloud still follows above the building, but can only strike creatures who are exposed to the sky. If you somehow move 100 ft. underground or otherwise your cloud would collide with a solid object of comparable size, the spell ends.