Australia & New Zealand: Surplus to persist in Western Australia, Northern Territory

Australia & New Zealand: Surplus to persist in Western Australia, Northern Territory

23 November 2024

THE BIG PICTURE
The forecast for the 12-month period ending in July 2025 anticipates that widespread extreme to exceptional surpluses will dissipate in northern regions of Australia, as will exceptional deficits in several regions of the continent. Severe to extreme surpluses will persist in isolated regions of Western Australia and Northern Territory. 

Severe to exceptional surpluses are anticipated in: 

  • Central Western Australia, in areas near Lake Wells. 

  • Southwestern Northern Territory, appearing in areas surrounding Lake Amadeus.

Moderate to severe deficits are anticipated in:

  • Southern coastal areas of Victoria, along the southern coast of the Barwon South West region. 

The 3-month maps (below) show the evolving conditions in more detail. 

FORECAST BREAKDOWN

The forecast through January 2025 depicts severe to extreme surpluses emerging in central Australia, in southern to southwestern areas of Northern Territory. Moderate to severe surpluses will expand in eastern coastal regions of southeastern Queensland and northeastern New South Wales. Severe to exceptional surpluses are expected to resolve into normal conditions in Tasmania and southern New Zealand. 

From February through April 2025, severe to extreme surpluses are expected to dissipate from central Australia, as well as eastern coastal regions. Much of the continent will experience near-normal conditions and abnormal deficits in northern areas. 

The forecast for the final months – May through July 2025 – indicates that near-normal conditions will remain throughout most of central and southern Australia, while northern areas of the continent may observe abnormal deficits. 

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS

A recent study found that the historic drought which occurred in Perth from October 2023 to April 2024 caused significantly unusual behavior in nearby bird species. Users of the eBird platform observed large increases of species like the black-shouldered kite, black-tailed nativehen, tawny-crowned honeyeater, and western spinebill, with some being seen nine times more often than usual. During the time period from October 2023 to April 2024, rainfall in the city was only 23 millimetres, which was the lowest since the 1870a, when records began. It was also one of the warmest summers on record, with temperatures 1.7°C higher than average.

Storms recently brought over 100 millimeters of rain to Western Australia’s South West region, which caused flooding and subsequent property damage. The town of Dardanup recorded 114 millimeters of rainfall in 24 hours, while the Ferguson Valley received 105 millimeters. Gnomesville, a popular local attraction, suffered damage, as well as nearby agricultural fields, which experienced flooded gardens and submerged crops. Additionally, local orange growers Rob Manning and Diana Neggo expressed concern over the potential for fruit diseases and splitting due to excessive water intake following the deluge. 

A recent study observed the impact of the 2019–2020 Australian megafires on local biodiversity. The fires burned over 10 million hectares – a globally unprecedented number. Data from over 2,000 species revealed the most significant effects occurred in areas with frequent or recent, severe fires, or in places that experienced extreme drought. Impacts of different areas varied, with rainforests and mammals showing the largest responses.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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