JED 1.6.0+ - No clouds

{
    "dimensions": [
        {
            "dim": 123,
            "dimensiontype": {
                "id": 123,
                "name": "Some Dimension",
                "suffix": "_dim123",
                "keeploaded": false,
                "worldprovider": "WorldProviderSurfaceJED",
                "require_exact_match": true
            },
            "jed": {
                "CloudRenderer": "DummyRenderer",
                "CloudHeight": 512
            }
        }
    ]
}