Issued on 4 September 2013
Continued easing of rainfall deficiencies in the southeast, little change for Queensland
August rainfall was below to very much below average across most of subtropical Australia, with large areas of northern New South Wales and the southeastern half of Queensland receiving monthly totals in the lowest 10% of records. The dry season continued in the north, seeing very low totals across tropical Australia. Most of Tasmania, southern Victoria west of Wilsons Promontory and southeastern South Australia recorded monthly totals in the highest 10% of records, largely clearing deficiencies from Tasmania and Victoria at the shorter timescale. Short-term rainfall deficiencies (2 to 3 months) are developing across parts of the east and west coast.
11-month rainfall deficiencies
Rainfall deficits for the 11-month (October 2012 to August 2013) period have seen improvement across the southeast; deficiencies have been cleared from Tasmania following that State's fifth-wettest August on record, while in Victoria only small areas of serious deficiencies (lowest 10% of records) remain in the northwest, central west, and northeast of Melbourne. Deficiencies in central and western Queensland remain similar to the previous 10-month drought period. The area affected by serious to severe deficiencies (lowest 10% to 5% of records) in southern Queensland, inland of the coastal ranges, and an adjacent part of northern New South Wales has increased. Deficiencies also continue in a small area of the Nullarbor Plain and near Shark Bay in Western Australia. Rainfall percentages for the 11-month period show much of Queensland west of the coastal ranges, northeastern South Australia, the Nullarbor Plain and parts of northern New South Wales have received less than 60% of their long-term average rainfall.
17-month rainfall deficiencies
Longer-term rainfall deficiencies for the 17-month (April 2012 to August 2013) period have been cleared from the few remaining areas experiencing deficit in Tasmania and seen improvement across central Victoria. Elsewhere deficiencies have generally worsened somewhat when compared to the previous drought statement. Serious to severe deficiencies persist along the west coast of Western Australia, across the Nullarbor Plain, northwestern Victoria and adjacent parts of the Riverina and southwest of New South Wales, in areas between northeastern South Australia and Queensland's Gulf Country, and in areas of southern Queensland and New South Wales west of the Great Dividing Range. The rainfall percentages map shows areas having received less than 65% of long-term average rainfall for the period are focused on eastern central Australia, inland areas of the eastern States and the Nullarbor Plain.
Weekly soil moisture levels in the upper soil layer have decreased dramatically compared to the weekly values one month ago across New South Wales, Queensland, the east of the Northern Territory and northeast of South Australia, with some areas ranking lowest on record. Soil moisture levels have also decreased across much of the west of Western Australia, the Nullarbor Plain and southern Southern Australia and are now below to very much below average across the west of Australia. Upper-layer soil moisture is near average in a band extending from the Kimberley and Pilbara in Western Australia through to the Eyre Peninsula in South Australia then turning to take in most of northern Victoria. Upper-layer soil moisture is above average to highest on record in southeast South Australia and parts of southwest Victoria, along the ranges from central to northeast Victoria and in the western half of Tasmania.
For the deeper layer, soil moisture generally shows a similar pattern to that of last month. Values have increased across lower southwest Western Australia, the far southeast of South Australia, southern Victoria and eastern Tasmania and are now near average in most of these areas but remain below average in eastern Tasmania and the central third of Victoria. Values have decreased across the Eyre Peninsula and Flinders Ranges in South Australia but remain above average. Other areas generally experiencing below-average soil moisture include the remainder of the South West Land Division of Western Australia, the eastern Top End and much of the Cape York Peninsula, northern Victoria and eastern New South Wales inland of the Great Dividing Range. Deep-layer soil mositure levels remain above average for large parts of northeastern South Australia, Queensland's Channel Country and east coast, and western New South Wales, although generally declining since last month.