The Bureau of Meteorology (BOM) says it expects Queensland's first cyclone this season will form by Sunday afternoon in the Gulf of Carpentaria, near the Northern Territory-Queensland border.
The BOM issued a cyclone watch for parts of the Northern Territory and Queensland, from Karumba to Nhulunbuy, including Mornington Island and Groote Eylandt.
BOM senior forecaster Gabriel Branescu said the system would be slow moving at first, before moving south-south-west towards the southern Gulf coast.
"It's likely to strengthen into a category 2 as it will move over southern parts of the Gulf," he said.
"It's likely to make landfall on the Northern Territory coast just outside the Queensland border on Monday.
"The system — if it develops — will be named Cyclone Esther."
Mr Branescu said the system could bring falls of up to 200 millimetres of rain to some parts.
"Mornington Island is likely to see damaging winds and possible destructive winds late Sunday and Monday and heavy and intense rainfall," he said.
"We are forecasting 200mm in a short period of time.
"There will also be heavy rainfall and possible gales in the north-western parts of the Gulf Country once the system approaches the coast on Sunday."
Parched inland gets soaked
Meanwhile, a separate weather system brought overnight thunderstorms and welcome rain to parts of central Queensland and the southern inland.
Yantumara in the central highlands received falls of 191 millimetres in the 24 hours to 9:00am.
Bauhinia Downs received 170mm over the same period, while Benaraby near Gladstone received 106mm.
Imogen Wathen, who lives on a beef cattle property between Yuleba and Wandoan in the southern inland, said the creek running through her property has broken its banks for the first time in decades.
"Upstream, they've had about 8.5 inches (215mm), so it's all come down and flooded our front creek," she said.
"My grandma's been here for about 60 years and she's never seen it break its banks, so it's pretty impressive."
"I definitely won't be getting back to town to go to work anytime soon."
Ms Wathen said plenty of fencing had been washed away, large gum trees were flattened and further west, neighbour Stuart Golden videoed a concrete tank floating away.
She said the rain had come after a drought in which 300 head of breeders were removed from her property and sent to the feedlot.
"Last year and 2018 were probably the worst we've ever seen it," Ms Wathen said.
"It was pretty dire before it started raining in late January.
"We've had over 200mm in the past month, so it's a completely different place."
Cyclone to cause localised flooding
The BOM said cyclonic conditions would likely ease Tuesday with the system expected to move west towards the central Northern Territory and away from Queensland.
It has asked people in those areas to consider what action they would take should the cyclone threat increase.
Localised flooding from cyclonic rainfall is expected to impact the north-west Gulf between the Queensland and Northern Territory border and Karumba.
Mornington Shire Council chief executive Frank Mills said the community was well prepared and would be keeping a close eye on the system.
"We're doing normal preparation — a community clean-up started on Friday and will finish today, we're getting information out to the community about taking shelter and having cyclone kits prepared," he said.
"[On Saturday] we'll have discussions about moving people into the aged care centre into the hospital and look at doing evacuations of vulnerable people off Mornington Island, so we're pretty organised.
"Our concern is if it increases intensity. [Our message is] be prepared, be ready and take action when necessary."
Mr Mills said the rain was welcome.
"The past couple of years the water supply has reached down to pretty horrendously low levels," Mr Mills said.
"Water storage is currently sitting at 75 per cent, so 200 to 300 millimetres of rain would hopefully bring that up to 100 per cent, which would be fantastic.
"Mornington fortunately is able to cope with large amounts of rainfall in short periods of time and it gets away quickly — our road network floods for extended periods of time but that's normal wet season."ABC