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For the 6 and 15-month periods ending 31st August 2008
A dry autumn and winter over most of Australia
LINKS:
rainfall deficiencies definition
6-month rainfall deficiencies
15-month rainfall deficiencies
Rainfall in August 2008 had little effect in alleviating long and short term
deficiencies over Australia. Below average rainfall over parts of eastern and southern Australia
maintained short and long-term deficiencies in these areas, slightly worsening short-term
deficiencies in southern Queensland into northern NSW, and in eastern Tasmania. Only minor
relief to the rainfall deficits in the southern NT resulted from the above average August
rainfall in the region, as the falls were generally light in absolute terms (August being a
climatologically dry month).
For the 6-month period from March 2008 to August 2008, areas of serious to
severe rainfall deficiencies covered much of the southern interior of WA and adjoining areas of
south-west NT; far western Queensland and the Barkly region of the NT; eastern Tasmania; and
eastern Victoria, extending into the far south-east of NSW. There were also isolated areas of
serious to severe rainfall deficiencies scattered through inland NSW, especially in the south
and in the northwest, extending into southern inland Queensland. This latter area of deficiencies
has slightly expanded in size due to below average rainfall in August. Below average rainfall in
eastern Tasmania has caused a slight increase in the severity of deficiencies in this area, with
an increased area of lowest on record. Small areas of lowest on record were also recorded in
far-eastern Victoria and central WA. In northern Australia, deficiencies were generally
indicative of an early end to the 2007/2008 wet season rains, whilst southern Australia has
generally experienced a poor start to the southern wet season. While not reflected in an increase
of the area of deficiencies, very much below average and lowest on record
August rainfall over much of southwest WA has placed severe
stress on cropping activities in the region.
Rainfall deficiencies for the 15-month period from June 2007 to August
2008 remain evident over much of SA, including most of the agricultural districts, the
southern NT and also in parts of southern WA, far western parts of both Queensland and
NSW, western and central Victoria and northern and eastern Tasmania. Over the 15-month
period, much of eastern Australia had some benefit from above average rainfall associated
with the 2007/08 La Niņa event. However, this was mainly from late 2007 to around February
2008, with typically below average rainfall since. Although Victoria received average to
above average falls over summer, the combination of very much below average rainfall since
the start of autumn 2008 and a dry winter in 2007, has resulted in central and western parts
of the state being in decile 1 for the 15-month period. Tasmania, central areas of Australia
and some southern parts of WA, which did not receive as much relief from the La Niņa event,
have also seen typically below average falls in recent months, leading to a continuation of
rainfall deficiencies over the 15-month period. The largest area of lowest on record rainfall
for the period is seen in eastern Tasmania north of Hobart, with only a couple of small patches
elsewhere. There were only marginal changes in the areas of longer-term deficiencies in August,
with a small expansion of the area of severe deficiency in southcentral WA and northern SA, and
a slight easing in western Victoria. Areas of long-term deficiencies generally highlight areas
that received little rainfall relief from the previous year's La Niña event, with
large areas of deficiencies through central and southern parts of Australia.
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. The combination of record heat and widespread
drought during the past five to ten years over large parts of southern and eastern
Australia is without historical precedent and is, at least partly, a result of climate
change.
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.
Rainfall
deficiency maps for standard periods out to three years are
available.
Note: The terms used to describe rainfall in these
Drought Statements have the following meanings -
Serious deficiency
- rainfalls in the lowest 10% of historical totals,
but not in the lowest 5%
Severe deficiency
- rainfalls in the lowest 5% of historical totals
Lowest on record
- lowest since at least 1900 when the data analysed begin
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
For more information regarding this rainfall
deficiencies statement, please contact the following
climate meteorologists in the National Climate Centre:
Lynette Bettio on (03) 9669 4165
Blair Trewin on (03) 9669 4623
David Jones on (03) 9669 4085
External Sites Relating to Drought
The Bureau of Meteorology does not make formal drought declarations
as these are done by either the relevant State Governments or by the
Australian Government. The Australian Government Program is called
Exceptional Circumstances
and it is administered by the Federal Department of Agriculture,
Fisheries and Forestry (DAFF). General information about Australian
Government drought assistance is available at
http://www.daff.gov.au/droughtassist.
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