How can I specify the direction of my wind?

Hello,
I am working on a scene with trees and grass, and I have implemented a background script that sends data to Unity specifying the direction of the wind. I would like to make the trees sway in the specified direction (Left or Right). Currently, I have checked the Wind Settings for Grass in the Terrain Settings and the Wind Mode, Wind Turbulence, etc in WindZone, but both of these settings are causing the trees to sway randomly, rather than in the direction I’m specifying.

Is there a way to set the direction of the wind and change it at runtime? I would appreciate any guidance on this matter.