SOI in Rapidly Rising Phase Dave McRae, Qld Climate Change Centre of Excellence, 04/04/10
The monthly value of the SOI rose in value from minus 10.8 for March to plus 12.1 for April placing the SOI in a Rapidly Rising phase.
Based on historical rainfall records and a Rapidly Rising SOI phase at the end of April, there is a reasonable 60 to 80% chance of getting above median rainfall across parts of north-west, central and south-east Queensland during May to July. Across the rest of the state there is a 40 to 60% chance of getting above median rainfall for May through to the end of July.
For example Tara has an 75% chance of getting above its May to July median rainfall of 98mm, Roma and Talwood have a 70% chance of getting above their May to July median rainfall of 90mm and 100mm respectively, Kingaroy has a 65% chance of getting above its May to July median rainfall of 105mm, and Pittsworth has a 60% chance of getting above its May to July median rainfall of 109mm.
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%.
If the SOI remains in positive values (> plus 5.0) it increases the chance of getting at least an average winter and spring. And unlike this time last year, sea surface temperature patterns are indicating the decline of an El Niño and not the development of one. For more climate related information, updates on SOI values and the latest outlook map go to www.longpaddock.qld.gov.au.