Seasonal Climate Outlook Message for January to April 2009

The bottom line

SOI remains Consistently Positive Dave McRae, Qld Climate Change Centre of Excellence 12/01/09

Based on the monthly SOI values recorded for November of plus 17.4 and for December of plus 11.6, the SOI has remained in a Consistently Positive phase.

An analysis of historical rainfall records and a Consistently Positive SOI phase at the end of December indicates a reasonable 50 to 70% chance of getting above median rainfall during January through to the end of March across most of Queensland.

The main exception is for the coastal strip running from the Hervey Bay district through to north of Rockhampton where there is a higher 70 to 80% chance of getting above median rainfall during January through to the end of March.

For example Gladstone has an 80% chance of getting above its January to March median rainfall of 415mm, Bundaberg has a 75% chance of getting above its January to March median rainfall of 460mm, Rockhampton has a 70% chance of getting above its January to March median rainfall of 350mm, Toowoomba has a 65% chance of getting above its January to March median rainfall of 310mm, Winton has a 65% chance of getting above its January to March median rainfall of 190mm and Yuleba has a 60% chance of getting above its January to March median rainfall of 190mm.

For more information on historical rainfall data for your region try Rainman Streamflow or www.bom.gov.au

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%.

For those who like to follow the relationship between the SOI and rainfall patterns in more detail, have a look at what happened in your area during January to March in the following years since 1950 that have had a Consistently Positive SOI phase at the end of December; 1950, 1955, 1961, 1970, 1975, 1988, 1998, 1999, 2000 and 2007.

Find out your average rainfall for January to March and see how many times rainfall was well below, well above or close to average during January to March in the listed years.

The 30 day average of the SOI as of 12 January is plus 13.2. You can receive a text message with the latest SOI values sent to your mobile phone. To subscribe to this free service, call (07) 4688 1459.