Northern Queensland is bracing for potentially dangerous flash flooding with intense rain forecast to lash the region.
Residents in Longreach, Winton and nearby towns have been put on alert by a severe weather warning for storms from Tuesday morning.
The Bureau of Meteorology says six-hour rainfall totals of up to 100mm are likely, and up to 150mm could hit some parts of the Central West.
"From (Tuesday) we'll start seeing a lot more rainfall in that central west area," senior forecaster Laura Boekel said.
"So Longreach and Barcaldine are where we can expect to see the bigger falls and we've issued a severe weather warning today for that area."
The rainband is expected to move toward the coast with heavy falls in Townsville and Cairns from Wednesday, with isolated thunderstorms predicted to dump up to 150mm.
The system has formed unusually late in the wet season and the expected rainfall totals could be up to five times the regional May average of 30mm, she said.
The weather bureau has placed more than 30 rivers and creeks on flood watch, including all of those flowing into the Gulf of Carpentaria, the Lake Eyre Basin and most between Townsville and Cairns.
It expects transport to be disrupted, with many catchments already saturated from the Anzac weekend floods and some still flooding.
Townsville Mayor Jenny Hill has put residents on alert, particularly in the city's north with 150 to 200mm of rain forecast for Wednesday.
"The concern we have, where we might see high intense rainfalls in less than two hours, the catchments are quite damp," Ms Hill said on Monday.
"So we are likely to see flash flooding, particularly around our northern beaches, around the Bohle and Black River areas."
"It's areas that we don't have any weirs or ability to regulate how the catchment operates that the community could be at risk."
In the state's far north, Cairns Regional Council told AAP rainfall is expected but won't exceed regular volumes for the region.
Out west in Winton, Mayor Gavin Baskett said more expected rain is a "godsend" that the region hasn't seen in May since Easter of 2008.
Two weeks ago, falls of between three and nine inches "put a smile on everyone's face".
"It couldn't get any better if we were to get a couple inches again now, that'll take us through the winter part of the year and lead into the back end of the year. It's a bit of a godsend really."
The system is expected to begin to clear toward the end of the week.