Outlook Improves Dave McRae Qld Climate Change Centre of Excellence 4th June 2007
There has been a slight improvement in the seasonal outlook for Queensland. Based on a Near Zero SOI phase at the end of May there is currently a 50 to 60% (with a few locations up to 70%) chance of getting median rainfall during June to August.
As most of the southern two thirds of Queensland will require several years of good rainfall to fully recover this should not be interpreted as the automatic start to drought-breaking rains. For there to be a lift in rainfall probabilities and a sustained and significant improvement in seasonal conditions, the development of consistently positive monthly SOI values would help.
The 30day average of the SOI has continued to trend slowly upwards to minus 0.4 as of the 4th June. Daily updates on the SOI are available on (07) 46881439 or at www.longpaddock.qld.gov.au
The next passage of the MJO is due to cross northern Australia in the second half of June (around the 20th). The timing of this MJO should coincide well with the onset of the Indian Summer Monsoon. The MJO is a band of low air pressure originating off the east coast of central Africa travelling eastward across the Indian Ocean and northern Australia roughly every 30 to 60 days. Research has shown the MJO to be a useful indicator of the timing of potential rainfall events (but not amounts). For more information try www.apsru.gov.au/mjo/
When using a climate forecast you should remember that the probability or percent chance of something occurring is just that - a probability. For example if there is a 70% chance of recording more than 100 mm there is also a 30% chance of recording less than 100 mm i.e. 70-30; 30-70. It does not mean that you will get 70% more than 100 mm or 100 mm plus another 70%.