A strong high-pressure cell is located over western Victoria and is expected to drift slowly southeast over the next 2 days.
Onshore winds on the northeast flank of this system will generate coastal showers for Queensland and NSW, and westerly winds on the southern flank will generate showers over western Tasmania.
Cloud has increased over northern areas of the NT and Queensland over the last 48 hours as an upper level trough begins developing and a surface trough is expected to form in response to this on Thursday.
This surface trough will then magnify over western Queensland on Thursday and Friday, and is likely to evolve into an east coast low on Sunday and Monday. As with the previous situation, there is considerable variation between the simulations as to the positioning and timing of this low.
Despite the uncertainties, this situation should produce large areas of rain across Queensland, NSW and eastern parts of SA from Thursday to Tuesday with widespread totals of 50 to 100 mm indicated on the rainfall simulation, mostly over eastern NSW. The heaviest falls – in excess of 100 mm are expected along the NSW coast in response to the east coast low and these will be across the period Sunday to Tuesday.
Because of last weeks rain many of the river systems over southern inland Queensland and central NSW will carry a higher degree of saturation, and the upcoming rain event may therefore produce more of an impact. And depending on the genesis and location of the east coast low, flooding along NSW coastal rivers will also be likely – again from Sunday to Tuesday.
An approaching cold front will generate showers and possible thunderstorms over southwest parts of WA today and tomorrow, and as this system moves east during the week, it will interact with the Queensland trough and further aid in it’s intensification.
We should finish the week and enter next week with another round of severe weather for eastern Australia – damaging winds, heavy rain and possible flooding.