Concern for rest of summer outlook (5th January 05)
The 30-day average of the SOI has remained in negative values over the last couple of months and as of the 5th January was minus 5.3. Based on the recent pattern of the SOI (minus 7.7 and minus 10.0 at the end of November and December respectively) there are some concerns the chance of getting normal rainfall across Queensland for mid to late summer has fallen.
While there is a 40 to 50% of getting normal rainfall for this time of year across the Darling Downs, southern border areas and far south west of Queensland, for the rest of the state the chance of getting normal rainfall for January through to the end of March is lower, predominately between 20 to 40%.
And in what would by now be a fairly familiar comment to regular readers of this column, for there to be an overall improvement in the seasonal outlook it would help if the SOI rose to a "Consistently Positive" phase for a couple of months at least.
The latest rainfall probability maps for Queensland, Australia and the world are at www.dpi.qld.gov.au/climate or www.longpaddock.qld.gov.au
As with any probability based forecast system it is important to consider the opposite aspect. For example, Bundaberg has around a 35% chance of getting above its normal January to March rainfall of 465 mm. This also means that there is a 65% chance of NOT getting the 465 mm over January to March.
Another way of looking at this is that in around 3 to 4 years out of 10 historically (or around one third) with the current SOI pattern, Bundaberg has received at least 465 mm over January to March. Therefore in 6 to 7 years out of 10 historically (or around two thirds), Bundaberg has gotten less than its normal 465 mm over January to March.
For more specific information refer to Rainman StreamFlow or the latest 'Climate Note' at www.dpi.qld.gov.au/climate Otherwise call the DPI Call Centre on 13 25 23 or (07) 3404 6999.