cumulonimbus

Dark storm clouds start concentrating in the sky. At the end of your turn, a cluster of storm clouds descents into your target location (in a 40ft radius sphere). The area within the cluster is heavyly obscured and difficult terrain. Flight within the clouds is not possible as raging winds make it impossible to control.
Every time a creature enters the cloud or starts its turn there, roll a d4. Depending on the roll, one of the following happens:
1 - A lightning strikes the creature. The creature and every other creature within 5ft roll a Dexterity Saving throw against your spell DC taking 4d10 lighing damage if failing or half as much if successful.
2 - A loud thunder is heard right above the creature's head. The creature and every other creature within 10ft roll a Constitution Saving Throw against your spell DC. These creatures are deafened until the end of their next turn and if they fail the saving throw, they also take 2d6 Thunder Damage.
3 - A sudden hail chills the creatures to its bones. The creature and every other creature within 10ft roll a Dexterity Saving Throw against your spell DC. Creatures that fail this saving throw take 3d6 Cold Damage and are vulnerable to lightning damage until the end of their next turn. If they succeed, they take half damage and are not vulnerable to lightning.
4 -  A gust of wind pushes the creature away. The creature must roll a Strenght Saving Throw against your spell DC. If they pass the saving throw, they take 2d6 bludgeoning damage as debris hit it. If they fail the saving throw, they are pushed 20ft in a random direction (roll a d8). If they hit another creature or an obstacle they stop, both take 2d6 bludgening damage per each 5ft moved (rounded up) and fall prone. If no obstacle is hit, it takes half the damage (4d6 bludgeoning) and doesn't fall prone.