Residents of two states are battening down the hatches as a slow-moving tropical low threatens to develop into Cyclone Esther in the Gulf of Carpentaria near the Northern Territory-Queensland border.
The tropical low in the Gulf's centre is predicted to strengthen into a category 1 system overnight, the Bureau of Meteorology says.
"The tropical low has resumed its southward movement over the Gulf of Carpentaria east of Groote Eylandt," the bureau said in an advice note on Sunday evening.
"It should continue to move southward and intensify and develop into a tropical cyclone tonight or early Monday morning."
It's likely the system will become a category 1 cyclone about 4am local time and it could briefly reach category 2 status as it makes landfall between Borroloola and Mornington Island about 1pm on Monday.
"Sometime in the early afternoon it will probably cross the coast, at this stage as a category 2," a bureau spokesman told AAP on Sunday night.
The region could receive up to 200 millimetres of rain west of Burketown to the Northern Territory border on Monday with the downpours continuing as the system slowly moves across the Top End.
"It will weaken after crossing the coast but we are expecting significant rainfall," meteorologist Shane Kennedy said.
Flood warnings are current for Gulf of Carpentaria catchments with more than 400mm of rain potentially falling within 48 hours.
There is a severe weather warning out for the gulf right up to the Torres Strait.
Abnormally high tides are expected to swamp the coast with large waves causing minor flooding.
Destructive winds with gusts up to 130km/h are possible in coastal areas between Borroloola and Mornington Island early on Monday as the system approaches.
The slow-moving system is expected to weaken as it moves toward the central Northern Territory before possibly affecting Western Australia later in the week.
Forecasters say the system could strengthen after passing over Western Australia and the cyclone may reform in the southern Indian Ocean and possibly make a second landfall on the Pilbara coast later in the week.
Australian Associated Press