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For the 5 and 6-month periods ending 31st October 2007
Another dry month for central and south-eastern Australia
LINKS:
rainfall deficiencies definition
5-month rainfall deficiencies
6-month rainfall deficiencies
Short-term rainfall deficits remain over SA and southeastern parts of the country as a result of
widespread below to very much below average October rainfall. Unless November is wetter than
average, 2006-07 will be one of the very few instances in history where the Murray-Darling
Basin (MDB) has suffered a winter-spring drought in successive years. The other years when
this has occurred were 1918-19 (the latter was extremely dry), and 1940-41, with 1940 being
very dry. In each of the years 1927, 1928, and 1929, large parts of the MDB had a winter-spring
rainfall total in decile 3 or lower, although individually none of the years was extremely dry.
See October
rainfall pattern
Since the start of winter, South Australia has been the worst hit state, with the five-month
average being the second lowest on record at just 36 mm. At the yearly time-scale (not shown),
rainfall deficiencies have weakened somewhat compared with the situation at the end of September
as October 2007 has generally had higher rainfall totals than October 2006.
For the 5-month period from June to October 2007, an area of serious to severe
rainfall deficiencies covered most of SA, southwest Queensland, western NSW, northern Victoria,
regions in the southern NT, scattered parts of WA and an area in northeastern Tasmania. Large
areas of lowest on record covered South Australia and southwestern Queensland into southeastern NT.
Rainfall deficiencies for the 6-month period from May to October 2007 were
widespread across the southern half of Western Australia as May rainfall was also below average
in this region. SA was also affected, but to a much lesser extent than for the five-month period.
There were small areas of lowest on record in these areas.
The deficiencies discussed above have occurred against a backdrop of
multi-year 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 MDB 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.
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:
Blair Trewin on (03) 9669 4623
Andrew Watkins on (03) 9669 4360
Grant Beard on (03) 9669 4527
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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