AN UNSEASONAL band of heavy rain is set to smash the east coast, with areas of NSW between Newcastle in the north and Wollongong in the south currently forecast to bear the brunt of the heaviest falls.
Current Bureau of Meteorology (BOM) models are showing the possibility for between 200-300mm in areas around Sydney and Wollongong, raising fears of flooding in the already saturated Hawkesbury and Nepean River catchments.
However, the BOM said on Friday there was still a degree of uncertainty in the forecasts as to where the largest rain totals will be recorded.
Further to the north, Brisbane is predicted to receive up to 100mm, well in excess of the average for the entire month of July of 24mm, while the Queensland central coast could see up to 150mm.
The system is already delivering significant totals, with unseasonable rain in Northern Territory during the dry season and totals in excess of 100mm recorded on Thursday in areas south of Cairns in north Queensland.
Falls in broadacre agricultural regions are not expected to be as significant although the Darling Downs and Central West NSW are both set to see potentially moderate falls, which could have implications for unharvested summer crop.
The rain is being caused by a coastal trough that is developing along the east coast and then deepening as it pushes south over NSW, with BOM reporting there is also the possibility of an east coast low developing and prolonging the rain event well into next week, which could also push heavy rain in southern NSW and far East Gippsland in Victoria.