Communities could be cut off from the rest of the country as heavy rains threaten to fill up rivers and ruin roads.
Communities across eastern Australia are under threat of floods as heavy rains and thunderstorms approach.
The weather warnings come as meteorologists consider whether to declare another La Nina event.
The Bureau of Meteorology has warned several rivers could overflow due to the expected rainfall, including the Lachlan River in NSW, the Avoca River in Victoria, and the Bulloo, Paroo and Diamantina rivers in Queensland.
But perhaps the starkest warning was issued to Northern Territory residents.
The BOM said localities in the Territory’s south could be isolated “for an extended period” if roads were impacted by the impending rains.
“A series of active troughs will move through central Australia on Sunday and during this week, causing an outbreak of thunderstorms bringing heavy rain which may trigger flooding impacts,” the bureau said in a warning.
“Catchments in the flood watch area are wet with some transport routes closed and minor flooding reported on the Stuart Highway. Wet catchments may become waterlogged quickly causing rapid creek rises.”
The thunderstorm system would shift to central and eastern areas by Tuesday, the forecast said.
Up to 50mm of rain could fall in certain areas of the Territory on Monday, the bureau said.
Areas expected to be affected included the Tanami Desert, Barkly, Central Desert, Western Desert and the MacDonnell Ranges.
People in those areas are advised to stay away from flooded waterways and drains, prepare ahead for flooding events and not drive into floodwaters.
The warnings came as meteorologists prepared to issue another “climate driver update”, which is used by the BOM to predict longer-term weather patterns.
The new update will come on Tuesday. A BOM spokeswoman declined on Monday to comment on what’s expected to be in the update.
The latest issue from October 26 said the likelihood another La Nina event would develop was around 70 per cent.
La Nina is a weather phenomenon linked to the shifting pattern of sea surface temperatures through the Pacific and Indian Oceans, which impacts rainfall and temperature variations in Australia.
Typically, La Nina is associated with heavier rainfall and more tropical cyclones.
The BOM most recently declared a La Nina event last September.
In the October 26 update, the weather experts wrote sea surface temperatures had cooled over a three-month period, “edging closer to La Nina levels”.
“Most international climate models surveyed by the bureau indicate weak La Nina conditions are likely for the coming months,” the update said.