THE monthly value of the SOI rose from minus 6.2 for August to plus 3.2 for September which places it in a "rapidly rising" phase.
Based on this SOI phase and historical rainfall records, throughout most of Queensland there is a 50-60% chance (with a few locations having up to a 70% chance) of getting above median rainfall during October-December.
For example, Roma has a 70% chance of getting above its October-December median rainfall of 165mm, Muttaburra has a 65% chance of getting above its October-December median rainfall of 182mm, Goondiwindi has a 55% chance of getting above its October-December median rainfall of 170mm and Dalby has a 50% chance of getting above its October-December median rainfall of 220mm (See map, top right).
The last time there was such a rapidly rising SOI phase at the end of September was in 2011.
Other years since 1950 with the same SOI phase at the end of September include 1970, 1979, 1983, 1989, 2001, 2005 and 2009.
When using a climate forecast you should remember the probability or percent chance of something occurring is just that - a probability.
Mundubbera for example, has around a 70% chance of getting above 200mm for October-December.
This also means that there is a 30% chance of not getting above 200mm.
Another way of looking at this is in around seven years out of 10 historically with the current SOI phase, Mundubbera has received at least 200mm during October-December.
Therefore in three years out of 10 with the current SOI phase, Mundubbera has gotten less than 200mm during October-December.
Given the El Niño like sea surface temperature pattern that remains in the Pacific it will be worth watching to see what trend SOI values take through to the end of the month.
For those interested the monthly SOI value for October last year was plus 11.1.
For more climate related information, updates on SOI values and the latest outlook map go to longpaddock.qld.gov.au.
Update your news preferences and get the latest news delivered to your inbox.