Ex-Tropical Cyclone Narelle has weakened to a tropical low after bringing heavy rain to already-saturated parts of the Northern Territory, but forecasters warn it could re-intensify into a severe cyclone and potentially threaten the Perth region this weekend.
The Bureau of Meteorology reports that the system is expected to move into the Indian Ocean on Tuesday evening, then track south parallel to the Western Australia coastline, regaining strength to become a severe cyclone by Wednesday evening. By Thursday, Narelle could become a category four system offshore, bringing strong and damaging winds.
Northern Territory Chief Minister Lia Finocchiaro expressed relief that the system had moved across the NT faster than expected, but noted significant rainfall had raised river systems and closed several roads, including the Stuart Highway near Adelaide River. Several communities, including Daly River, Adelaide River, and Katherine, were warned of minor to major flooding after over 100mm of rain fell on Sunday.
Meteorologist Ilana Cherny said the system would move into the northern Kimberley region of Western Australia on Monday afternoon, bringing damaging winds up to 100km/h and heavy rain with flood risks. By Friday, the system may track further south to central and southern parts of WA, but there is less confidence in forecasts beyond that point.
Cherny noted that while it is unusual for a cyclone to impact so far south, there are historical precedents, including Cyclone Alby in 1978 and Cyclone Seroja in 2021. Narelle formed south of the Solomon Islands last Tuesday, and climate scientists point to record ocean temperatures that likely helped the system gain strength. Dr Hamish Ramsay of the CSIRO said the last tropical cyclone to cross Australia from east to west was Steve in 2000, making Narelle a relatively rare event.
