An unusually slow-moving weather system has dragged monsoonal rain from tropical north Queensland to the state’s south-western outback, already dumping a year’s worth of rain in places in a matter of days – with the promise of more to come.
So widespread is the deluge that, by Sunday, the entire sunshine state was expected to be sodden with more than 100mm of rain, Dean Narramore, senior meteorologist at the Bureau of Meteorology said on Tuesday morning.
People in the deserts and channel country of the far south-west could be isolated for days, Narramore said, as flood waters take weeks to flow into Lake Eyre and north-east South Australia.
“Basically, anywhere inland of the ranges in Queensland, and also around the north tropical coast, is either in a flood watch or a flood warning,” Narramore said. “And the forecast over coming days is rainfall will continue”.
The last three or four days brought widespread rainfalls to towns spanning central, western and southern Queensland, including Birdsville (126mm), Windorah (171mm), Quilpie (200mm), around the Winton area (120mm), Mount Isa (about 100mm) and Urandangi (135mm), Narramore said.
“Pretty much everyone from Mount Isa to Cloncurry, Hughenden and all the way down to the New South Wales and the South Australian border has had 100mm to 200mm,” he said.
To put those totals in perspective, Narramore said the average annual rainfall, particularly in the far south-west, was between about 180mm and 300mm.
“So many places have had three, six and even up to nine months’ worth of rainfall – and that’s only at our official gauges,” he said. “There’s a number of property owners out there that have recorded falls in excess of 200mm over the last few days … the isolated high falls out there could easily see some places with nine to even 12 months’ worth of rainfall already.
“We’ve already seen pictures of what looks like inland lakes forming”.
Narramore said the system was moving slowly east every day. Far-western Queensland could see another 25mm to 50mm, with isolated falls of up to 100mm, while farther inland, places Hughenden, Longreach and Charleville could see another 100mm to 200mm over the next three or four days.
“That rain eventually will get towards eastern Queensland, where we could see another 100mm to 150 mm there, but probably not until the weekend,” Narramore said.
“Not the big falls we’ve seen inland, but definitely the soaking rainfall might even extend towards the east coast – so … by the end of the week, the entire state of Queensland is probably going to experience up and over 100mm of rain”.
The forecaster said the rain was caused by an upper low pressure system coming from the Northern Territory and dragging “all that monsoonal moisture” from the Top End.
“All that monsoonal moisture is being fed into this very slow moving low pressure system over south west Queensland, which is driving days of rain, flooding and storms,” he said.
“Normally we might see this for a day or two, but the prolonged nature of this system is the unusual side of it”.
