Issued on 5 December  2013 by the National Climate Centre

Rainfall deficiencies continue in eastern Australia

November rainfall  was above average across the tropical north of Australia, along the eastern coast of the mainland and eastern Tasmania, as well as  parts of southeast  Western Australia.   Below-average monthly totals were recorded in a broad area of the inland southeast and central Australia, and scattered areas of inland and southern Western Australia.

The distribution of rainfall deficits for the 14-month (October 2012 to November 2013) period remain similar to the previous (13-month) period. Serious to severe deficiencies (lowest 10% to 5% of records) are in place across much of western and central Queensland  and adjacent New South Wales border areas. Most of Queensland west of the ranges, northern New South Wales, northeastern South Australia and the southeastern Northern Territory has received less than 65% of the long-term (1961-1990) average rainfall for the 14-month period.Significant November rainfall in the Gulf Country of Queensland has eased deficiencies in this region.

The longer-term rainfall deficiencies for the 20-month (April 2012 to November 2013) period have also eased in the Gulf Country and the Nullarbor Plain, but increased in expanse in central and inland southeastern Australia compared to last month. Serious to severe deficiencies persist between Geraldton and Shark Bay on the west coast of Western Australia, across parts of the Nullarbor Plain, a large area encompassing much of the far north of South Australia, the southeastern Northern Territory and southwestern Queensland, and across eastern Australia west of the Great Dividing Range from northwestern Victoria well into southern Queensland.  The rainfall percentages map for the 20-month period shows that inland eastern Australia, South Australia away from the coastal fringe, the southern and central Northern Territory, and areas extending from the western Gascoyne east to the Eucla region of Western Australia have received less than 80% of the long-term average rainfall for the period.  Some parts of the eastern interior have received less than half their average rainfall over this period.

Significant areas of eastern Australia, South Australia and the southeastern Northern Territory continue to see rainfall deficiencies over shorter periods (3 to 6 months).

Soil moisture in the upper soil layer has improved in northern Australia and along the south and east coast (including eastern Tasmania), but has decreased on the west coast of Western Australia. Weekly soil moisture levels remain very much below average across a broad area of inland southeast and central Australia and areas of western and central Western Australia. Soil moisture is also below average, but less severely so, in northwestern Victoria.

In the deeper layer, weekly soil moisture generally shows a similar pattern to that of last month, with a further decrease across the southeast. Values are very much above average for a large area of Western Australia between the eastern Pilbara/western Kimberley and the southern Interior. Soil moisture is somewhat above average across small areas of South Australia, western and central New South Wales, east coast and western Queensland, and the Southeast Coastal and Goldfields districts of Western Australia. Soil moisture is below average across the eastern Top End, the western and northern Southwest Land Division, and southwestern Gascoyne in Western Australia, the Nullarbor Plain, areas along the ranges along the east coast, and on Cape York Peninsula, in the Gulf Country and on northern Queensland coast. Despite the widespread rainfall deficiencies in the region, deep-layer soil moisture is close to normal in most of western Queensland, due to the ongoing influence of the very wet conditions which prevailed from 2010 to early 2012.

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Black and white version

What is drought?

Drought is a prolonged, abnormally dry period when the amount of available water is insufficient to meet our normal use. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of rainfall deficiencies. Agriculturalists rate the impact on primary industries, hydrologists compare ground water levels, and sociologists define it by social expectations and perceptions.

Rainfall averages, variability and trends

An area experiences a rainfall deficit when the total rain received is less than the average rainfall for that period.

• Average rainfall: How much rain do you expect?
• Rainfall variability: How consistent is rainfall in your area?
• Rainfall history: Check tables, graphs and data from your local weather station.
• Rainfall trends: Has your rainfall changed?

Drought declarations and assistance

Formal drought declarations are handled by State or Federal Government.
Further details