Seasonal Climate Outlook Message for December 2006 to March 2007

The bottom line

SOI in Rising Phase Dave McRae 02/12/06

Based on the SOI and historical rainfall records, for December through to the end of February there is a 50 to 70% chance of getting median rainfall for south west Queensland, a 20 to 40% chance of getting median rainfall for central and northern Queensland and a 40 to 60% chance of getting median rainfall across the rest of the state.

For example Adavale has a 69% chance of getting its December to February median rainfall of 140 mm, Morven has a 63% chance of getting its December to February median rainfall of 213 mm, Blackbutt has a 50% chance of getting its December to February median rainfall of 325 mm, Allora has a 47% chance of getting its December to February median rainfall of 257 mm, Clermont has a 35% change of getting its December to February median rainfall of 308 mm and Bowen has a 30% chance of getting its December to February median rainfall of 512 mm.

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%.

If an area has a low chance of getting above median rainfall it does not mean there will be no rainfall. As we are entering our summer rainfall season there is a reasonable chance of getting some useful relief rain. The latest rainfall probability maps are at http://www.dpi.qld.gov.au/climate or http://www.longpaddock.qld.gov.au and daily updates on the SOI are available on (07) 46881439. For more on rainfall probabilities for your location refer to Rainman StreamFlow or contact 132523 or (07) 3404 6999.

The full story

SOI in Rising Phase D McRae 02/12/06

Monthly SOI values rose from minus 16.4 for October to minus 0.7 for November. Based on this shift in value the SOI is now in a "Rapidly Rising" phase which gives a mixed seasonal outlook across Queensland. Based on the SOI and historical rainfall records, for December through to the end of February there is a 50 to 70% chance of getting median rainfall for south west Queensland, a 20 to 40% chance of getting median rainfall for central and northern Queensland and a 40 to 60% chance of getting median rainfall across the rest of the state.

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 December to February in the following years that have had a 'Rapidly Rising' SOI phase at the end of November; 2001, 1993, 1984, 1981, 1976, 1973, 1969, 1960, 1959, 1947, 1946, 1934, 1918, 1912 and 1906. For example at Kilcoy, below average rainfall for December to February in those years was recorded 3 times, close to average rainfall was recorded 9 times with above average rainfall recorded 3 times. Therefore rainfall during December to February at Kilcoy is more likely to be close to average than well below or well above average. For more information refer to Rainman StreamFlow.

The first of the summer Sorghum Crop Shire Yield Outlooks for this season has been released by the DPI&F. In what would not be a surprise the chance of getting an above median sorghum yield on a shire basis during the 06/07 summer growing season is below average for most of northern NSW and Queensland.

Based on soil water conditions at the end of October and the seasonal rainfall outlook for November to January most cropping regions in central and southern Queensland have a below to very much below average crop yield expectation. Throughout northern NSW, sorghum shire yield forecasts are marginally higher and closer to average. As it is early in the growing season, widespread useful rain would improve the current outlook.

The regional sorghum crop outlook is based on the assumption of cropping after a winter fallow and does not take into account effects of poor crop nutrition or damage due to pests, diseases, heat or frosts. For more information on shire wheat yields contact Andries Potgieter on (07) 4688 1417.

Information on ocean temperatures in the central Pacific (running eastward along the equator from the international dateline) continues to indicate a warming trend characteristic of an El Nino. As we have stated over the last six months, if this pattern persists it most likely will have a drying effect on our expected rainfall in spring and early summer as it did this winter over much of eastern Australia. A common feature of an El Nino SST pattern is a later than normal start to the monsoon season. Its effect (or impact on expected rainfall) is usually less noticeable in mid to late summer for the northern half of Australia. For more on conditions in the Pacific try the Bureau of Meteorology at www.bom.gov.au/climate/ahead/

What is interesting is since 1990 there have been 8 identified El Nino events; 1991/92, 1992/93, 1993/94, 1994/95, 1997/98, 2002/03, 2004/05 and now 2006 which is an average of 1 every 2 years. This compares to 3 identified la Nina events; 1996/97, 1998/99 and 2000/01 which is an average of approximately 1 every 5 years.

Is the recent run of El Nino events a result of climate change? As our climate is influenced by both natural variability (eg orbital cycles, volcanic activity) and human induced environmental changes (eg greenhouse gases from power stations) it is difficult to say that individual events such as cyclones or droughts are the direct result of human induced climate change. However it is worth noting that the 2001 Inter-governmental Panel on Climate Change Report (IPCC) stated that 'El Niño events are becoming more common' and 'more El Niño-like mean conditions' may prevail in the future. A new IPCC report is due next year.

While not every drought is the result of an El Nino and not every El Nino brings widespread drought across Australia, an increase in the frequency of these events will impact on business, agriculture and regional communities. I do not think this means shutting up shop. What I do think it means is that now is the time to look at how to adapt our industries and practices to handle these potential changes.

As expected the MJO is currently influencing our weather. Although much of the moisture that was present in the system has dissipated, there is still the potential for patchy storm rain for Qld, NSW and Victoria. Based on its current timing another MJO event would be expected in early to mid January. The MJO is 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 (but not amounts). For more information try http://www.apsru.gov.au/mjo/ or http://www.bom.gov.au/climate/tropnote/tropnote.shtml

* Climate Internet Sites

http://www.dpi.qld.gov.au/climate The Queensland Department of Primary Industries and Fisheries (DPI&F) Climate and Systems Technologies (CST) web site contains the 'Current Climate Note' and other updates including the latest on the SOI, rainfall probabilities for Queensland and Australia. It includes information on sea surface temperatures, regional crop outlooks and information on services, workshops and products.

http://www.longpaddock.qld.gov.au/ The Queensland Department of Natural Resources and Water climate web site contains detailed information on the current climate situation including Sea Surface Temperatures (SST), value of the Southern Oscillation Index (SOI), recent rainfall events, seasonal outlooks, drought maps and pasture growth forecasts.

http://www.bom.gov.au/climate The Australian Bureau of Meteorology web pages contain information on the current season, climate forecasts, climate averages and extremes, climate change, climate data, climate model outputs and precipitation and temperature seasonal outlooks.

http://www.cpc.ncep.noaa.gov/ The Climate Prediction Centre (CPC) in the United States has a useful internet site for monitoring conditions (westerly wind bursts, Kelvin wave activity, sea surface and sub-surface temperatures etc) in the Pacific. ENSO Diagnostics Discussion in the Climate Highlights section is highly recommended for those interested in progress of El Niño/La Niña state.

http://iri.ldeo.columbia.edu/ International Research Institute providing precipitation and temperature seasonal forecasts for Africa, Asia, Australia, Europe, Middle East, North America, Pacific Islands and South America. The site also has a large number of technical reports, information on the state of ENSO, summary of recent climate events and impacts and has a strong focus on capacity building and education.

When I'm asked about how climate information can be used I refer to a couple of key points developed from client feedback. Key points include that management decisions should never be based entirely on one factor such as a climate or weather forecast. As always, everything that could impact of the outcome of a decision (soil moisture, pasture type/availability, crop and commodity prices, machinery, finance, costs etc) should be considered. For example, the level of soil moisture at planting is the major factor influencing crop yield or success.

An interesting site http://www.managingclimate.gov.au/ from the 'Climate Variability In Agriculture' (CVAP) research and development program is well worth looking at. It highlights some case studies on how producers and businesses have used (to varying levels of success) climate and weather information in their decision-making processes.

Last updated: 3 December 2006

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