This spell requires the priest to concentrate and cast the spell for the full duration of the spell. The casting time and duration are simultaneous; both activities occur in the same turn.
In the first round of casting, the priest summons an enormous black storm cloud over the area of effect. Lightning and crashing claps of thunder appear within the storm; creatures in the area of effect must make a saving throw or be deafened for 1d4 turns.
On the second round, acid rains down in the area, inflicting 1d4+1 points of damage. No saving throw is allowed.
On the third round, the caster calls six lightning bolts down from the cloud. Each is directed at a target by the priest (all may be directed at a single target or they may be directed at six separate targets). Each lightning bolt strike causes 8d8 points of damage (a successful saving throw indicates half damage).
On the fourth round, hailstones rain down in the area, causing 3d10 points of damage (no saving throw).
On the fifth through tenth (and final) rounds, violent rain and wind gusts reduce visibility to five feet. Movement is reduced 75%. Missile fire and spellcasting from within the area of effect are impossible.
The sequence of effects ceases immediately if the priest is disrupted from spellcasting during the 1 turn duration of the spell. The priest may opt to cancel the effects at any time.