A cold pool of air over the interior of the country is letting a trough develop over the eastern states. This has a feed of tropical moisture and will create widespread rain from Thursday.
High pressure will keep alpine areas dry for the rest of the week (with cold nights continuing). The rain system will develop further as a centre of low pressure tracks southeastwards across New South Wales on the weekend. Rain falls to the east and south of the low.
The system is very cold right now, but there is a feed of warm, tropical air. By the time it reaches us, it will have warmed up significantly, and will bring rain to alpine areas from Saturday night. See the outlook for how this system will change to snow early next week.
The low will deepen off the New South Wales coast on Monday and eventually move away on Wednesday - but cold fronts will be moving past (to our south) on Friday, Sunday and Tuesday - and there is a strong chance for an injection of polar air from these. If the low is near, it will be heavy precipitation; lighter if further away; and we have to see how it crosses New South Wales first, to see where it ends up. The injection of colder air should let it be snow that is falling next week, up high.
Commentary above courtesy of Jane's Weather. www.janesweather.com