Issued 2 April 2008
Short-term rainfall deficiencies expand in central Australia
Short-term rainfall deficiencies expanded and intensified in central
Australia as a result of below average March rainfall. In addition,
continued higher than average temperatures exacerbated the effects of
these rainfall deficits. In parts of eastern and southern Australia, there
was a slight easing of rainfall deficiencies at the two-year timescale,
although the overall pattern remains the same.
See March rainfall pattern
6-month rainfall deficiencies
For the 6-month period from October 2007 to March 2008, an area of serious to severe rainfall deficiencies covered much of the southern half the Northern Territory and some adjacent areas in far western Queensland. There were also some smaller patches near Marree in South Australia with serious to severe deficiencies. Maximum temperatures of one to two degrees above average have worsened the dry conditions.
24-month rainfall deficiencies
Rainfall deficiencies for the 24-month period from April 2006 to March 2008 were analysed in southwest WA, Tasmania, southeast Queensland, northern SA and in a band stretching from the Bight coast of SA across much of Victoria and the western slopes and plains of southern NSW. The pattern is very similar to that observed at the end of February, but as March 2008 was wetter than March 2006 in most areas, there was some easing of these two-year deficits. One exception was the Eyre Peninsula and Bight coast of SA which was drier this year so the 24-month deficits intensified. Record-low falls were evident in western WA, on the Eyre Peninsula in SA, near Melbourne and in eastern and northern Tasmania.
The worst of the long-term deficiencies are likely to remain for some time. For example, above to very much average rainfall (deciles 8-10) is needed in the rainfall deficient areas over the next six months just to elevate totals since April 2006 out of the lowest decile.
The deficiencies discussed above have occurred against a backdrop of decade-long rainfall deficits and record high temperatures that have severely stressed water supplies in the east and southwest of the country. Several years of above average rainfall are required to remove the very long-term deficits. Furthermore, the combination of heat and drought during the past five to ten years over the Murray Darling Basin and southeastern Australia is outside the typical range of variability experienced during the previous 100 years. For more information go to a Special Climate Statement on the six years of widespread drought in southern and eastern Australia, November 2001 to October 2007
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