Ex-Cyclone Narelle Poses Dual Threat: Flooding in NT and Potential Perth Impact
Communities across Australia's far north are on high alert as ex-Tropical Cyclone Narelle continues its westward trajectory, having already unleashed significant rainfall and flooding in the Northern Territory. Forecasts now indicate the system could re-intensify over the Indian Ocean, potentially threatening the Perth region by the weekend.
Immediate Flooding Concerns in the Northern Territory
Narelle weakened to a tropical low on Monday after dumping over 100mm of rain on already-saturated parts of the Northern Territory over the weekend. This deluge has led to river systems swelling rapidly, prompting warnings of minor to major flooding in several communities, including Daly River, Adelaide River, and Katherine.
Key infrastructure has been affected, with the main Stuart Highway near Adelaide River closed due to rising waters. Northern Territory Chief Minister Lia Finocchiaro expressed relief as the system neared the West Australian border, but cautioned that significant rainfall had already caused disruptions and raised river levels.
Forecasted Re-intensification and Western Australia Threat
According to the Bureau of Meteorology, Narelle is expected to move into the Indian Ocean by Tuesday evening, then travel south parallel to the Western Australia coastline. Meteorologist Ilana Cherny stated that the system will spend considerable time over water, creating favourable conditions for it to regain strength.
By Wednesday evening, Narelle could become a severe tropical cyclone, with potential to escalate to a major category four system by Thursday. This could bring damaging winds and coastal impacts as it tracks southward towards central and southern parts of Western Australia.
Unusual Weather Patterns and Historical Context
Cherny noted that it is unusual for a cyclone to impact areas as far south as Perth, but historical precedents exist, such as Cyclone Alby in 1978 and Cyclone Ned in 1989. The current forecasts suggest Narelle may make a journey of at least 5,000km across the continent, a rare event last seen with Tropical Cyclone Steve in 2000.
Dr. Hamish Ramsay, a climate and cyclone expert at the CSIRO, explained that most tropical cyclones weaken over land but can persist as tropical lows. If these lows re-emerge over warm ocean waters, they can quickly regain strength, a phenomenon observed with Narelle.
Climate Factors and Broader Implications
Narelle formed south of the Solomon Islands in the Coral Sea last Tuesday, with climate scientists linking its intensity to record ocean temperatures. This event underscores the role of global heating in fueling severe storms, raising concerns about future weather patterns in Australia.
As the system approaches Western Australia, there is potential for welcome rainfall in agricultural districts north of Perth. However, authorities remain vigilant, with less confidence in forecasts beyond Friday regarding potential landfall or continued cyclone status.
Residents in affected areas are advised to monitor updates and prepare for possible flooding and strong winds as Narelle's path evolves.
