An upper level trough is interacting with a cold front over South Australia (and spreading cloud and patchy rain over eastern Australia). It is borderline cold enough, but should bring 10 to 20 cm of snow above 1600 metres on Tuesday and Wednesday, as the front slides across the southeast.
Another system will bring more snow on Thursday and early Friday - and this airmass is different, it is very cold. The trailing high stays back west of Perth, allowing a stronger front to cross the Bight. This one will have a trough in behind, which will bring a second surge. There should be 20 to 30 cm of snow, falling down to 600 metres under the cold pool on Thursday.
The next high moves in to start the weekend, encouraging dry weather.
The next high is overhead on Sunday then to our east from Monday.
Interesting to note that another surge of moisture looks set to come in from the Indian Ocean (we need that for heavy snow). The next system should arrive mid next week, hopefully turning that moisture into snow.
Commentary above courtesy of Jane's Weather. www.janesweather.com