Seasonal Climate Outlook Message for April to July 2007

The bottom line

SOI Near Zero

Dave McRae 2nd April 2007

There has been little shift in the monthly value of the SOI for February (minus 2.8) and March (minus 1.2). This places the SOI in a "Consistently Near Zero" phase. Based on this SOI phase and historical rainfall records, for April through to the end of June there is a 40 to 60% chance of getting median rainfall throughout Queensland. Further analysis also indicates rainfall during these 3 months is likely to be closer to the long term median than well above median.

As we are in the autumn predictability gap it will be interesting to see what direction the SOI takes. At this a time of year a return to consistently negative values would be a warning sign for a likely dry winter/spring. In terms of a state wide improvement in seasonal conditions the development of consistently positive SOI values and even a La Nina (and maybe a bit of luck) would help.

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%.

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). It is next due in mid April. For more information try www.apsru.gov.au/mjo/

Daily updates on the SOI are available on (07) 46881439 or at www.longpaddock.qld.gov.au For more information refer to Rainman StreamFlow, www.dpi.qld.gov.au/climate or contact 132523.

The full story

SOI in Near Zero Phase Dave McRae 2nd April 2007

As part of an AGO and Cotton CRC funded project, DPI&F are running some climate change in cotton communities workshops. The 3 hour workshops are open to anyone and aim to cover the basics of climate change - the causes, the evidence and the likely impacts. The workshops also aim to have a general discussion on what adaptation strategies there may be for agriculture, business and rural communities.

Workshops are planned for Dalby on the 24th April, St George on the 26th April, Goondiwindi on the 27th April and Emerald on the 1st May. For more details or to RSVP contact Dave McRae on (07) 46881459 or david.mcrae@dpi.qld.gov.au

There has been little shift in the monthly value of the SOI for February (minus 2.8) and March (minus 1.2). This places the SOI in a "Consistently Near Zero" phase. Based on this SOI phase and historical rainfall records, for April through to the end of June there is a 40 to 60% chance of getting median rainfall throughout Queensland. Further analysis also indicates rainfall during these 3 months is likely to be closer to the long term median than well above median.

There is a lower 30 to 40% chance of getting median rainfall in parts of south west WA, much of the northern and the south east corner of SA, the northern half of Victoria and border regions with NSW as well as the central coast of NSW. Similar to Queensland, throughout the rest of Australia there is a 40 to 60% chance of getting median rainfall during April to June.

As we are in the autumn predictability gap it will be interesting to see what direction the SOI takes. At this a time of year a return to consistently negative values would be a warning sign for a likely dry winter/spring. In terms of a state wide improvement in seasonal conditions the development of consistently positive SOI values and even a La Nina (and maybe a bit of luck) would help.

The MJO is next due in mid April (as at time of writing 2nd April). It will be interesting to see what, if any rainfall events it triggers. Widespread rain is still needed promote pasture growth and improve soil moisture levels for the coming winter cropping season. 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 www.apsru.gov.au/mjo/

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%.

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 April to June in the following years since 1930; 1930, 1932, 1933, 1934, 1936, 1938, 1940, 1942, 1944, 1946, 1948, 1949, 1953, 1954, 1957, 1958, 1962, 1963, 1965, 1972, 1982, 1995 and 1996. Work out your long term average rainfall for April to June and see how many times rainfall was well below, well above or close to average.

For example at Taroom, well below average rainfall for April to June in those years was recorded 3 times, close to average rainfall was recorded 15 times with above average rainfall recorded 5 times. Therefore rainfall during April to June at Taroom is more likely to be close to average than well below or well above average.

The Bureau of Meteorology has released the seasonal climate summary for the 2006/07 summer. For Queensland below average summer rainfall was recorded over the south east, Capricornia and parts of the Central Coalfields and Maranoa with above average rainfall recorded across the south west and north tropical coast.

Rainfall totals were particularly low especially for the Darling Downs and Granite Belt. Record low summer rainfall totals were recorded at a number of places including Nobby with 106.5 mm (average 294 mm) and Ballandean with 127.6 mm (average 289 mm). Summer temperatures for Queensland were generally milder than average though both hot and cold extremes set new summer records. The hottest summer day was 46.9 degrees C at Cloncurry and Winton. The coldest night was 7.6 degrees C at Applethorpe and Stanthorpe. If you interested if during the last season or month it was hotter or colder or wetter or drier than normal the climate summary reports issued by the Bureau make interesting reading. They are readily available at www.bom.gov.au/climate/current and are best of all free.

In the latest El Nino wrap-up available at www.bom.gov.au the Bureau of Meteorology state that sea-surface temperatures in the central and eastern Pacific have remained close to average during March, following the rapid cooling that took place during January and February at the end of the 2006/07 El Niño event. Trade Winds, the SOI and Pacific cloud patterns are currently in a neutral phase. At this stage there is only a low risk of a return to El Niño conditions in 2007, a slightly higher than normal chance of a La Nina developing with continuation of neutral the more likely outcomes.

As autumn is a key time for the establishment of climate phenomena such as El Nino and La Nina we recommend closely monitoring what happens over the next few months. Daily updates on the SOI are available on (07) 46881439 or at www.longpaddock.qld.gov.au For more information refer to Rainman StreamFlow, www.dpi.qld.gov.au/climate or contact 132523.

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.

A simple cost benefit analysis when making a major decision may also be useful. For example what will I gain if I get the desired outcome? What will I lose (sleep, money, family relationships) if I do not get the desired outcome and what other options (risk neutral) are there? A PART OF THIS PROCESS IS TO HELP MANAGERS TO BE CAREFUL NOT TO CHANGE FROM NORMAL RISK MANAGEMENT TO HIGH LEVEL RISK TAKING BASED ON A PIECE OF INFORMATION (SUCH AS A CLIMATE FORECAST).

Forecasts as well do not always give a strong signal as to likely conditions for your location. In assessing climate forecasts as a management tool consider the level of signal for the key decision times in your location. Rainman StreamFlow is a useful tool for this.

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.