A MONSTER rain band, extending the entire length of the east coast and pushing relatively deeply into inland agricultural areas is set to deliver up to 50mm over much of Queensland, NSW and Victoria this week.
Reaction to the fall is expected to vary markedly.
In northern summer cropping regions it will be well received as vital moisture for thirsty sorghum and cotton crops, but in southern and western Victoria, where winter crop harvest continues, it raises the fear of possible downgrading of standing crop.
Bureau of Meteorology (BOM) duty forecaster Tom Delamotte said the rain was likely to build up from this afternoon (Wednesday), with showers and isolated storms crossing western Victoria and Central West NSW.
“Northerly winds will start to bring down tropical moisture from the Queensland coast,” Mr Delamotte said.
“As we move overnight a strong upper level trough will approach from the west, and the interaction with the cold air through the upper level and the warm humid air mass means a low pressure system will form over central Victoria.”
He said this would spark areas of rain from the west, with scattered thunderstorms.
“The heaviest rain in Victoria will be over central and eastern areas, with widespread falls of up to 50mm.
“For the areas where there are embedded thunderstorms we could see falls of 100mm, even in lowland areas.
“Places such as Melbourne and other central areas could be those that see those heavier falls.”
Further to the west, the rain grades lighter on Thursday, with 15-30mm expected.
On Friday, a secondary front will hit eastern South Australia and southern parts of Victoria, however Mr Delamotte said guidance was now suggesting less rain with this front than previously expected.
“A lot of the rain now looks like slipping away to the south, there will be general falls of 5-20mm across southern and western Victoria.”
Thursday and Friday look like being the wettest days for NSW, with the heavier falls likely to extend as far west as Nyngan.
In the north, Queensland looks like picking up moisture from Friday onwards, with falls right through until Sunday.
There are good falls predicted for summer cropping regions such as the Darling Downs and Liverpool Plains.
Mr Delamotte said it was one of the more widespread systems in terms of range this year.
“We’ve had systems deliver heavier rain to smaller areas but in terms of widespread falls this is right up there.”