Issued on 8 November 2013
Rainfall deficiencies continue in eastern Australia
October was a dry and unusually warm month for Australia (14th driest on record, 7th warmest for mean temperature) with below average rainfall affecting most areas. The only regions to experience above average rainfall were coastal areas in the southeast and far northwest, with small pockets of above average rainfall scattered around the northern tropics and Western Australian Goldfields.
13-month rainfall deficiencies
The distribution of rainfall deficits for the 13-month (October 2012 to October 2013) period remain similar to the previous 12-month period, and have increased in severity and expanse in eastern Australia. Serious to severe deficiencies (lowest 10% to 5% of records) are in place across much of western Queensland and in a broad band inland of the coastal ranges, extending from the Gulf of Carpentaria to just across the New South Wales border. Most of Queensland west of the ranges and northern New South Wales has received less than 65% of the long-term (1961–1990) average rainfall for the 13-month period.
19-month rainfall deficiencies
Similarly, longer-term rainfall deficiencies for the 19-month (April 2012 to October 2013) period have also increased compared to last month. Serious to severe deficiencies persist between Geraldton and Shark Bay on the west coast of Western Australia, across the Nullarbor Plain, between northeastern South Australia and Queensland's Gulf Country, and across eastern Australia west of the Great Dividing Range from northwestern Victoria well into southern Queensland. The rainfall percentages map for the 19-month period shows that, away from the coast, eastern Australia, South Australia and the southern half of the Northern Territory have received less than 80% of the long-term average rainfall for the period. Further inland much of this area has only received 50% to 70% of the average rainfall for the period.
Significant areas of eastern Australia continue to see rainfall deficiencies over shorter periods (2 to 6 months), as well as those above.
Soil moistureReflecting below average rainfall and unusually warm temperatures, soil moisture levels in the upper soil layer have decreased across most of mainland Australia. Weekly soil moisture levels are very much below average across southern and western Queensland, New South Wales, most of South Australia and adjacent parts of Western Australia. Soil moisture is also below average, but less severely so, across Victoria and the greater southeast of South Australia (east of Spencer Gulf), most of the Northern Territory excluding the Top End and parts of Western Australia including the eastern Kimberley and a broad strip stretching from the Pilbara to the Eucla District. Soil moisture levels have decreased across northern Tasmania with levels near average across the northeastern half of the state and above average in much of the northwest, central plateau and Derwent and Huon valleys.
In the deeper layer, weekly soil moisture generally shows a similar pattern to that of last month, with continued 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 top of the Eucla District. 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, much of the South West Land Division of Western Australia (excluding the southwest, where values are near average), the Nullarbor Plain, the coast of the Cape York Peninsula and parts of inland eastern Queensland, parts of east coast Tasmania, and most of Victoria and eastern New South Wales inland of the ranges. The areas along the ranges on the east coast saw the most significant decrease in soil moisture compared to last month.
Lowest on record - lowest in the historical analysis, which runs from 1900.
Severe deficiency - rainfalls in the lowest 5% of historical totals.
Serious deficiency - rainfalls in the lowest 10% of historical totals, but not in the lowest 5%.
Very much below average - rainfalls in the lowest 10% of historical totals.
Below average - rainfalls in the lowest 30% of historical totals, but not in the lowest 10%.
Average - rainfalls in the middle 40% of historical totals.
Above average - rainfalls in the highest 30% of historical totals, but not in the highest 10%.
Very much above average - rainfalls in the highest 10% of historical totals.
Product Code IDCKGD0AR0