Where did the cretaceous weather come from?

The anwser is simple it came dowm from the tropics. Looking at the lastest satellite image, which I got from the Bureau of Meterology's satellite page. You can see the big band of cloud coming down the east coast of Australia. A tropical Low (low pressure area) in Northern Australia had connected with low coming acrosss the Great Australian Bight and it just sucked all the hot moist air south (where it is needed)