Australia & New Zealand: Water deficits diminish but persist in Tasmania and South Australia

24 January 2018

THE BIG PICTURE
The 12-month forecast (below) indicates exceptional water deficits in South Australia covering the Eyre Peninsula and reaching past Adelaide to the eastern border with Victoria; dotted along Victoria’s coast to Melbourne; in much of Tasmania; and the southwest tip of Western Australia.

From South Australia, moderate to extreme deficits will emerge, forming a vast fan in the center of the country into Northern Territory and Queensland. Deficits of equal intensity are forecast for NT’s Top End surrounding Darwin.

Moderate deficits are expected along the Darling River but more severe deficits are forecast in the eastern Murray-Darling Basin. Intense surpluses are forecast for northeastern QLD west of Bundaberg.

Moderate to exceptional deficits are forecast for New Zealand and moderate deficits are forecast for New Caledonia.

IMPACTS
Rainfall from a January subtropical storm reportedly trumped the sum total over the prior two months in Auckland, New Zealand. At least one coastal town was evacuated before high winds and a king tide combined with the rain to shut down power to 20,000 households and flood several communities, damaging homes, boats, and roads. Storm water overflowed into local swimming areas around Auckland, affecting water quality and prompting warnings for beach-goers. Costs of New Zealand storm and flood insurance claims have surged 70 percent, due to a high number of claims filed over the last three years, among other factors.

The drought-afflicted southern region welcomed the rain as it abated wildfire risk. The dramatic storm landed just over a week after the federal government made financial assistance available to dairy farmers struggling with recent drought.

In Australia, two-thirds of Queensland remained drought-declared at the end of 2017, some regions since April 2013. The drought has affected livestock ranchers and farmers and has cost the state government $143 million (US$114.7 million) in drought assistance.

Extremely dry conditions in New South Wales produced conditions so dangerous that the state equestrian championships - a qualifying event for riders competing for spots on Australia's Olympic team - were canceled. One Olympian competitor said it was the worst conditions he'd ever seen.

FORECAST BREAKDOWN

The 3-month maps (below) for the same 12-month period show the evolving conditions.

Exceptional deficits observed in recent months in Australia are forecast to nearly disappear. However, severe to exceptional deficits are expected to persist in western Tasmania through March, downgrading thereafter, and in the far southwestern tip of Western Australia near Busselton. The near-term forecast through March also includes moderate deficits in South Australia which will become severe to extreme past the Eyre Peninsula to the Victoria border and along Victoria’s coast past Melbourne. Moderate deficits are expected along the Darling River and in the eastern Murray-Darling Basin, but deficits may be more severe in Riverina. Some primarily moderate surpluses remain in the forecast in eastern Queensland near Bundaberg. Moderate surplus conditions are also expected in Northern Territory’s Top End near Daly Waters, but some severe deficits are forecast to persist farther north near Darwin. Primarily moderate deficits are forecast for New Zealand with small pockets of more severe conditions. Conditions in New Caledonia are expected to be near-normal.

From April through June deficit anomalies in Australia will be primarily mild, with severe deficits in West Australia near Busselton, and some moderate deficits along the Darling River and its tributaries in New South Wales. Surplus conditions near Bundaberg in QLD should transition to near-normal. Moderate to severe deficits will continue to emerge in Tasmania and New Zealand.

The forecast for the final months – July through September – indicates moderate to severe deficits across northern Australia, the southwestern tip of Western Australia, and eastern Tasmania.

(It should be noted that forecast skill declines with longer lead times.)

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