Seasonal Climate Outlook Message for December 2004 to March 2005

The bottom line

Climate Watch 14th December 2004

The recent storm generated rain has provided a good start to summer with most areas of the state having received some rainfall and the indicators are that this pattern is likely to continue.

Recent rainfall maps are available at www.bom.gov.au One thing that stands out though when looking at these maps is that most areas of the state still have some way to go before 'above average' rainfall has been recorded.

So for those looking for some more rain, our next best 'climate induced' opportunity will be with the next passage of the MJO. The last active phase of the MJO across Australia occurred in early November.

Over the last couple of weeks the MJO weakened and stagnated. However recent activity in the Pacific suggests it is re-establishing so its next passage should occur in late December or even into very early January.

The MJO is simply 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 across much of Queensland.

Given the growing interest in the MJO, and with funding from the DPI&F, GRDC and CRDC we have developed a site www.apsru.gov.au/mjo/ that will allow anyone interested to track its passage.

As of the 13th December the 30day average of the SOI is minus 6.2. Daily updates on the SOI are available on (07) 46881439.

Despite this fall in value of the SOI there still remains a 40 to 60% chance of getting above median rainfall through to the end of February across most of the state.

As with any probability based forecast system it is important to consider the opposite aspect. For example, Charters Towers has around a 70% chance of getting above 270 mm over December to February. This also means that there is a 30% chance of NOT getting the 270 mm over December to February.

Another way of looking at this is in around 7 years out of 10 (or around three quarters) with the current SOI pattern, Charters Towers has received at least 270 mm over December to February. Therefore in 3 years out of 10 (or around one quarter), Charters Towers has gotten less than 270 mm over December to February.

For more information we recommend referring to Rainman StreamFlow, www.dpi.qld.gov.au/climate www.longpaddock.qld.gov.au or call the DPI Call Centre on 13 25 23 or (07) 3404 6999.