Meteorologists say a monsoon trough and an embedded low over the Gulf of Carpentaria will converge over southern Cape York and cause severe thunderstorms from Wednesday night and into Thursday.
The Bureau of Meteorology has put communities between Aurukun, Croydon and Doomadgee on flood watch with 25 rivers and creeks at risk of breaking their banks as the rainfall sets in.
"Riverine and localised flooding, including flash flooding, is likely, which is likely to cause disruption to transport routes and isolation of some communities," a bureau alert said on Wednesday afternoon.
"Some bridges and crossings are already flooded with the Peninsula Development Road currently closed at multiple locations."
People living on the coast between Hope Vale and Cardwell, including Cairns and Port Douglas, will bear the brunt of the heavy rain from Wednesday night.Â
The bureau said six-hour rainfall totals of between 100mm and 150mm are likely with intense six-hour rainfall totals of up to 300mm, which could trigger dangerous and life-threatening flash flooding.
"There remains significant uncertainty over the timing and location of this threat, and a separate severe thunderstorm warning will be issued if this eventuates," the alert said.
Cairns Regional Council has opened four sandbag stations across the northern city, urging people to protect their homes before the downpours.
"Residents in low-lying areas should prepare their properties for potential flooding," the council said.
Western Cape coastal communities and islands between Aurukun and Delta Downs Station, including Mornington Island, Kowanyama and Pormpuraaw, are set for heavy rain and potential flash flooding from Wednesday afternoon.
The rainfall will then move south and east with six-hour totals between 100mm and 150mm possible across Normanton, Burketown, Karumba, Doomadgee and Croydon.
The Bureau of Meteorology said minor flooding is already occurring along the Norman River at Normanton and more rainfall could cause it to rise to above a moderate level of 4m from Thursday, and potentially even higher.
