Seasonal Climate Outlook Message for September to December 2003

The bottom line

SOI Remains Near Zero (Dated 24/09/03)

The 30day average of the SOI has remained close to zero and as of the 24th September is minus 1.8.

Based on the recent pattern of the SOI there remains a 30 to 50% chance of getting above the long term September to November median rainfall for northern, central and western Queensland. For the south east quarter of the state, the chance of getting above the long-term median rainfall is a marginally higher at 50-60%.

For increased confidence in seasonal conditions improving for summer, the SOI needs to return to more sustained positive values.

Many people like to follow the timing of the MJO (also know as the 40day wave). The MJO is simply a band of low atmospheric pressure originating off the east coast of central Africa travelling eastward across the Indian Ocean and northern Australia roughly every 30 to 50 days.

While it is a tropical phenomenon, it appears to indicate the timing of potential rainfall events (but unfortunately not rainfall amounts) over central and southern Queensland.

The next passage of the MJO is expected to influence our weather in early October.

Last updated: 23 September 2003