SOI Remains on Roller-coaster Ride 23/06/2004
The SOI has fallen quite rapidly since the start of the month. As of Wednesday the 23rd June the 30day average of the SOI is minus 6.6 (down from plus 13.0 at the end of May).
It will be very interesting to see if this downward trend continues over coming weeks and months. While in the short term it will not impact on rainfall probabilities, a fall back into a "Consistently Negative" SOI pattern would create problems with the seasonal outlook later in the year.
For example, a "Consistently Negative" SOI phase at the end of August means there would be a very low (less than 30%) chance of getting above median rainfall for September to November across Queensland. This type of pattern is also usually associated with a later than average start to the spring/summer rainfall season.
This is an example of why I continue to recommend a cautious approach when considering the longer-term outlook.
It's also worth remembering that we are approaching our "traditional dry season" of July, August and September. While at times there have been some exceptional rainfall events during those months, the big well above average falls many people now need are not common.
In my opinion for there to be an overall improvement in the seasonal outlook, it would help if the SOI were to remain in a "Consistently Positive" pattern for a couple of months at least. If you like to more closely follow the SOI, daily updates are available on (07) 46881439.
We are also offering a free 3month trial of a SMS text SOI update. A SMS message will be sent to your mobile twice a week. If you are interested in receiving the SOI update give me a call through the DPI&F Call Centre on 132523.
It would appear the latest passage of the MJO has already passed with unfortunately little impact on our weather. Many grain growers in southern Qld were hoping that this passage of the MJO would provide some planting rain. As well, producers in central Queensland were hoping for some relief from intensifying dry conditions.
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.
Based on its recent timing it would next be expected to have an influence on our weather around late July.
Given the interest in the MJO, and with funding from the DPI&F, GRDC and CRDC we have developed a site http://www.apsru.gov.au/mjo/ that will allow anyone interested to track its passage.
For more information contact me through the DPI&F Call Centre on 13 25 23.