Issued on 7 November 2012
October rainfall lowest on record for southern Australia - deficiencies in WA and SA continue, expanding in NSW.
7-month rainfall deficiencies
There has been a slight worsening of rainfall deficiencies in affected areas of Western Australia, South Australia, and New South Wales over the 7-month (April to October) period. Most of the Interior district and southern Western Australia as well as South Australia west of Marree and north of Port Augusta have experienced 7-month rainfall in the lowest 5 per cent of records. This continues the expansion of rainfall deficiencies over the past few months; see 6-month and 5-month rainfall from April 2012. Deficiencies in southern New South Wales have also expanded.
October rainfall, averaged across southern Australia (i.e. south of 26°S), was the lowest on record although deciles were less impressive on a location-by-location basis. Much of southwestern Western Australia, parts of the arid regions of South Australia, northeastern New South Wales, and northern Tasmania received rainfall in the lowest 10 per cent of records. Rainfall across southern Australia was also below average for both September and August; averaged over the three months August–October, rainfall in southern Australia was the second-lowest on record.
3-month rainfall deficiencies
The 3-month (August to October) deficiency map now shows a broad band of severe deficiencies (lowest 5 per cent of records) from southeastern Western Australia, through northern South Australia, extending to the east coast although deficiencies become discontinuous across northern New South Wales and southern Queensland. Above-average September rainfall in southwest Western Australia has aleviated 3-month deficiencies, although October was quite dry for much of the region.
The western half of southwest Western Australia continues to experience long-term rainfall deficiencies - see for example the most recent 36-month period. The southwest region had its driest year on record in 2010, and the two-year period 2010–2011 was the driest on record in some parts of southwest Western Australia, so that below average rainfall conditions experienced in 2012 are exacerbating pre-existing rainfall deficits.