The folder path can't be a URL. It has to be a file path.
If it will always begin with: https://www.mywebsitename.com then you could probably use something like:
'UploadFolder' => "".str_replace("https://www.mywebsitename.com","../..",$WADAcac_prod_subcategory_NEW_update->getColumnVal("prod_url")) ."",