Seasonal Climate Outlook Message for December 2002 to March 2003
The bottom line
Marginal Improvement in Outlook Dated 03/12/02
There has been a very slight improvement in the rainfall outlook for summer (December to February). However we remain concerned about the outlook in the longer term.
While the improvement in rainfall probabilities for December to February indicate the potential for some useful relief rain for Queensland, an El Nino sea temperature pattern still persists in the central Pacific Ocean. Therefore there remains only a very low chance of getting the well above average rainfall needed to break the ongoing drought.
Based on the recent SOI pattern, the probability of receiving or getting above the long term median rainfall for December to February has improved slightly to between 40-60%.
When dealing with probabilities it is important to consider the additional information provided. For example, based on the recent pattern of the SOI there is a 40% chance of getting above the long term December to February median rainfall of 414 mm at Gympie. Therefore there is a 60% chance of not getting the long term December to February median rainfall.
Another way of looking at this is that in 4 years out of 10 (or less than half) with the current SOI pattern, Gympie has received its long term median December to February rainfall. Therefore in 6 years out of 10 with the current SOI pattern (or more than half), below median rainfall has been recorded at Gympie for December to February.
Also of concern is the latest United States Climate Prediction Centre forecast which highlights the potential for this El Nino event to persist for another year.
This section will be updated on the 11/12.
The full story
Marginal Improvement in Outlook Dated 03/12/02
There has been a very slight improvement in the rainfall outlook for summer (December to February). However we remain concerned about the outlook in the longer term.
While the improvement in rainfall probabilities for December to February indicate the potential for some useful relief rain for Queensland, an El Nino sea temperature pattern still persists in the central Pacific Ocean. Therefore there remains only a very low chance of getting the well above average rainfall needed to break the ongoing drought.
The monthly value of the SOI for October was minus 7.6 and for November was minus 4.1. Based on these monthly values the SOI is in a "Near Zero" phase. The 30day average of the SOI as of the 2/12 is minus 5.5. Daily updated SOI values are available on (07) 46881439.
Based on the recent SOI pattern, the probability of receiving or getting above the long term median rainfall for December to February has improved slightly to between 40-60% (refer to map).
When dealing with probabilities it is important to consider the additional information provided. For example, based on the recent pattern of the SOI there is a 40% chance of getting above the long term December to February median rainfall of 414 mm at Gympie. Therefore there is a 60% chance of not getting the long term December to February median rainfall.
Another way of looking at this is that in 4 years out of 10 (or less than half) with the current SOI pattern, Gympie has received its long term median December to February rainfall. Therefore in 6 years out of 10 with the current SOI pattern (or more than half), below median rainfall has been recorded at Gympie for December to February.
Other years that have had the same SOI phase in November include 1902, 03, 07, 20, 26, 27, 31, 32, 37, 45, 52, 53, 54, 58, 66, 67, 68, 78, 79, 80, 83, 85, 87, 90, 95 and 1996.
What were rainfall patterns and farming conditions like for December to February in your area for those years? The Long Paddock internet site www.longpaddock.qld.gov.au/ has maps showing the rainfall patterns across Australia for those years.
The recent brief rise in the SOI value during November may be reflecting some instability in the current El Nino pattern. Despite this brief shift in SOI value it is expected that the El Nino pattern will continue through to at least Autumn 2003.
Also of concern is the latest United States Climate Prediction Centre forecast which highlights the potential for this El Nino event to persist for another year.
The 30-50day intra-seasonal oscillation (also know as the MJO) is simply a band of low atmospheric pressure that originates off the east coast of central Africa. It travels eastward across the Indian Ocean and northern Australia roughly every 30 to 50 days. While it is mainly a tropical phenomenon, it appears to indicate the timing of potential rainfall events (but not indicate rainfall amounts) over central and southern Queensland.
The use of the MJO as a reliable forecast tool is still at the research/experimental stage. The last passage of the MJO occurred in mid November as a fairly inactive event and did not help trigger any widespread rainfall events. It is next expected late in late December/early January.
Information from the Bureau of Meteorology www.bom.gov.au also suggests that the development of the northern Australian monsoon season is also unlikely to occur before late December/early January.
For more specific rainfall data for your location refer to Australian Rainman or contact the DPI Call Centre on 13 25 23. The latest outlook maps are also available on the DPI climate page www.dpi.qld.gov.au/climate
