Issued 3 March 2008
Short-term rainfall deficiencies develop in the southeast and central NT
Despite a La Niña event contributing to above average rainfall
across parts of tropical and eastern Australia, the southeast of the NT
has been much drier than normal since the start of the northern wet
season in October. In addition, higher than average temperatures have
exacerbated these rainfall deficits. In parts of eastern Australia, there
was a slight easing of rainfall deficiencies at the two-year timescale,
although the overall pattern remains the same.
See summer rainfall pattern
5-month rainfall deficiencies
For the 5-month period from October 2007 to February 2008, an area of serious to severe rainfall deficiencies developed in the southeast of the Northern Territory and the adjacent far west of Queensland. There were also some smaller patches near and to the north of Tennant Creek in the Barkly district. 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 March 2006 to February 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 January, but as February 2008 was substantially wetter than February 2006 in eastern Australia, there was some easing of these two-year deficits in southeast Queensland and southern NSW. Record-low falls were widespread along the west coast of WA and in eastern Tasmania, with a few patches in the southeast of the mainland.
The worst of the long-term deficiencies are likely to remain for some time. For example, above to very much above average (deciles 8-10) rainfall is needed in the rainfall deficient areas over the next six months just to elevate totals since March 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 recent 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