You use the Cloud Editor to create your clouds for a terrain. When you build the weather file in the CE, it produces a .awa file that you stick into your terrain's folder. Then, when you Build the terrain, you now have default weather (cloud) patterns for that terrain, Be it offline or online, it is now part of the terrain and will show up. You can also create a new .awa file (to use in events or whatever) and send it to Skuzzy. When he places that new .awa in, it overrides the terrain's default cloud patterns that you placed in for the default.