In the explanation of Basic Wind Speed under the Wind Load Parameters for ASCE 7, it states "Specifies the three-second gust speed at 33 ft. (10 m.) above ground for Exposure C category as...".
What is the elevation of the "above ground" here? Is it sea level? Average altitude from sea level? I know it can not be the project's plant ground elevation because Caesar would not know this.
Can somebody please explain this to me. Any help would be appreciated. Thanks.

"I know it can not be the project's plant ground elevation because Caesar would not know this." Well, let Caesar know it and check the global coordinate of your first node - make sure the elevation of your model is "correct" vs wind definition.

About ASCE 7-16, there is a coefficient Ke Ground elevation factor indented to correct the air density considering your site elevation vs sea level (but often is taken as Ke=1) and a Velocity Pressure Exposure Coefficient Kz which considers the effects of gradient of the velocity in the boundary layer "above site ground".

When you input the wind shape factor Caesar asks for that node's global position; this is where you tell the program how far off the ground the start of your model is located.