There is concern a tropical low brewing off northern Australia may reach cyclone intensity west of Darwin by Boxing Day.
A severe weather warning was issued for parts of the Northern Territory’s Arnhem district early on Christmas morning.
Forecasters said a monsoon was likely to strengthen across the northern Top End during Saturday as a tropical low deepens near the Tiwi Islands.
The trough was expected to be near the Australian coastline during Saturday, then move inland by evening.
The worry is that the low is likely to strengthen as it moves south and may reach tropical cyclone intensity west of Darwin on Sunday.
A tropical cyclone advice warning is current for the system, which is expected to feature heavy rain leading to flash flooding during Saturday across the northern Arnhem.
Damaging winds with gusts of up to 100 km/h with monsoonal squalls may develop about the coast from Saturday evening.
These conditions may persist or even increase during Sunday.
A flood watch is also current for parts of the Top End.
Locations which may be affected include Maningrida, Milingimbi, Ramingining, Galiwinku, Warruwi and Gunbalanya.
Northern Territory Emergency Service advises people to secure loose outside objects and seek shelter when conditions deteriorate.
Motorists should pull over if it’s raining heavily and avoid driving into water of unknown depth and current.
Residents are urged to create their own sandbags if there is flooding and to stay away from flooded drains, rivers, streams and waterways.