Ardashir's Blinding Whirlwind

A violent sandstorm materializes as a 20ft Sphere at a point you can see within range. The area inside the sandstorm is Heavily Obscured and Difficult Terrain, and lasts for the duration.

As a bonus action on your turn, you may increase or decrease the radius of the Sphere by up to 5ft (to a maximum of 120ft), OR move the Sphere up to 30ft to a point you can see within range.

If the sandstorm interacts with a strong wind (such as one created by Gust of Wind), it becomes Lightly Obscured while the wind blows, but is otherwise unaffected.

Using a Higher-Level Spell Slot. The sandstorm’s initial radius may increase by 5ft, and the increase/decrease/movement options are +5ft, for each spell slot level above 3.