Seasonal Climate Outlook Message for October to January 2003

The bottom line

No Change In Outlook (Dated 23 October)

The key point at present is the continuation of hot and dry conditions for most of eastern Australia for October to December. Currently there is a low 20-40% chance of getting of median rainfall for the next 3 months for most of Queensland. However, for southern and far western Queensland marginally higher probabilities (40-50%) indicate the increased potential for some relief rainfall.

The 30day average of the SOI as of the 23rd October was -8.9. If the SOI remains negative through to the end of the month low rainfall probabilities would be expected to continue.

The 30-50day intra-seasonal oscillation (also know as the MJO) is simply a band of low atmospheric pressure that originates off the east coast of central Africa. It travels eastward across the Indian Ocean and northern Australia roughly every 30 to 50 days. While it is mainly a tropical phenomenon, it appears to indicate the timing of potential rainfall events (but not indicate rainfall amounts) over central and southern Queensland by helping to enhance atmospheric activity such as upper level low pressure systems.

The use of the MJO as a reliable forecast tool is still at the research/experimental stage. The DPI and the Uni of Southern Queensland currently have a study project under way looking at the use of the MJO as reliable rainfall prediction tool for Queensland. The last passage of the MJO occurred in late September as a fairly inactive event and did not help trigger any widespread rainfall events. It is next expected around early November. However at this stage the MJO signal is still quite weak.

As many producers are interested in how climate forecasts can be used in management decisions I suggest reading the interesting case studies developed by the Land and Water Resources Research and Development Corporation (LWRRDC) Climate Variability in Agriculture Program (CVAP). The case studies which can be found at the web site www.cvap.gov.au/mastersoftheclimate/ highlight how some producers use climate information in their management decisions. I believe these case studies are well worth reading.