Low Clouds/Weather Mask Like Citadel in Half Life 2

Hello Community!

I wanted to consult and seek guidance. I’m working on a Space Elevator and I’d like it to effect the weather around it. I’m curious how to best make an effect like the Citadel in Half Life 2 or low clouds that mask the top of a skyscraper.

How would you archive effects like this? Would you build a custom sky material, use niagara around the building or make localized fog — or a combination?

Thank you for taking the time to help. I appreciate it!