A large upper and surface low is expected to start taking shape in the Great Australian Bight during the middle of the week before drifting across southeast Australia later in the week and weekend.
This system as well as an accompanying cold front is forecast to cause some showers to start developing in parts of South Australia on Thursday. These should then spread into northeastern and central parts of the state on Friday, possibly also into far southwest Queensland and far northwest New South Wales with some associated rain areas and storms developing.
On Saturday, the main focus of this activity is likely to shift into inland New South Wales and southern inland Queensland before moving towards eastern NSW and northeast Victoria on Sunday while slowly weakening.
On average, 20 to 40 mm of total rain accumulation is currently expected in far southwest Queensland, far northwest New South Wales and far northeast South Australia with locally much higher amounts likely for those places which experience a storm. Near the edge of these areas, lighter falls of around 5 to 15 mm are likely.
Some localised flash flooding potential can't be ruled out for any areas which experience a storm. It should be remembered though that these rain amounts and areas are still subject to change.
Image 1: EC ensemble 7 day total rain accumulations (Source: weather.us)