The coming rain event will be as widespread and beneficial as events in early June and late May for most of the southeast mainland, but possibly the best since January for some. The system is already forming over Western Australia and gaining moisture while waiting for a strong cold front to make its way from Antarctica to give it a kick. It appears that the coldest, most unstable air will form over South Australia and head east across Victoria, New South Wales and southern Queensland from Monday to Wednesday. A large area across these states will benefit the most from the cold, unstable air by receiving heavy showers and thunderstorms. While some moisture is being drawn from the Indian Ocean, most of it will be sourced from the Pacific. This means that the highest rainfall is most likely to be near the NSW and Queensland east coast and ranges, where 30 to 50 millimetres is possible.