A trough, a cold front, and a subsequent low off the coast could see some good falls of rain along the southern ranges, and extending up to the mid-North Coast and Hunter from today.
Parched Dubbo could see a day of rain, but the totals will not be great, possibly a bit more than 10mm, but it will fall throughout Tuesday.
Parts of the south-east will see between 15-30mm today, with snow falling down to 1000m as temperatures plummet from weekend highs in the mid-20s to maximums of just into double figures on Tuesday.
The parched Canberra district could receive between 10-20mm tonight and into early Tuesday. Canberra had received just 4mm this month, when its average September rain is 52mm. Albury and Goulburn could also pick up some decent totals.
Weatherzone forecaster Kim Westcott said the weather event over the next few days could see some solid falls in the parched Hunter Valley, with rain stretching up to Scone. Differing weather models suggest the possibility of up to 50mm over the three days with a low forming off the coast on Tuesday.
"The benefit will be this system is a bit slow moving so we will see rain falling through to Wednesday in some areas, before it moves away. We could see a return to a few more showers by the weekend. This system will largely affect the south-east and the ranges."
A low off the coast on Tuesday will see quite good falls of between 25-50mm up from the Illawarra to the Mid-North Coast, with many areas in the Hunter to benefit.
A rare stratospheric weather event could see some new weather patterns evolve as a "whole lot of cold air had been bumped around", Ms Westcott said.