Mystara Spells - Level 4 - Storm Sphere

Description - You create a area of whirling air.

Spells - Level 4 - Storm Sphere

Evocation 4th Level (Lightning, Storm)
Secret Crafts - Air, Elements, Nature
Casting time - 1 action
Range - Long (120ft)
Area - 20ft radius sphere
Components - V, S
Duration - Concentration (1 minute)
Saving Throw - Strength negates
A area of whirling air springs into existence, centred on a point you choose within range. The sphere remains for the spell’s duration. Each creature in the sphere when it appears or that ends its turn there must succeed on a Strength saving throw or take 2d6 bludgeoning damage. The sphere’s space is difficult terrain.
Until the spell ends, you can use a bonus action on each of your turns to cause a bolt of lightning to leap from the centre of the sphere toward one creature you choose within 60ft of the centre. Make a ranged spell attack. You have advantage on the attack roll if the target is in the sphere. On a hit, the target takes 4d6 lightning damage.
Creatures within 30ft of the sphere have disadvantage on Wisdom (Perception) checks made to listen.
Cast at Higher Levels - (+1) increase the damage by 1 dice.