Seasonal Climate Outlook Message for November 2002 to February 2003

The bottom line

(Dated 13/11/02)

The 30day average of the SOI has risen since the start of the month and as of the 13/11 is +2.8.

Despite the rise in value of the SOI the chance of getting above the long term median November to January rainfall remains low at 10-40% for most of Queensland.

It is worth remembering that this does not mean Queensland will miss out totally on all rain this summer, as there is always the chance of some relief rainfall. However, there is currently only a low chance of getting the well above average rainfall needed to break the current drought.

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. It can help 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 last passage of the MJO occurred in late September as a fairly inactive event and did not help trigger any widespread rainfall events. At this stage the MJO signal remains quite weak. However it is expected to influence our weather for the next week.