Seasonal Climate Outlook Message for February to May 2006
The bottom line
SOI remains stable 08/02/06
Based on a "Rapidly Rising" SOI Phase at the end of January there is a 50 to 70% chance of getting above median rainfall across parts of north west and central west Queensland during February to April. For the remainder of the state there is a 30 to 50% chance of getting above median rainfall.
As of Wednesday the 8th February the 30day average of the SOI is plus 11.0. It will be interesting to see if positive SOI values are maintained, or if the roller coaster ride the SOI has been on continues. As stated previously, for an overall widespread improvement in conditions across the state it would help if the SOI was in consistently positive values for a few months at least.
Queensland has been experiencing extreme climate anomalies over the last two months. For example December was the warmest month ever recorded for Queensland - see http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/timeseries.cgi, while January was the second warmest January experienced. This anomalous warmth has covered the whole of eastern Australia - December/January is by a large margin the warmest period experienced. January also saw the warmest nation wide minimum temperature on record (suggesting that not only was it hot but the atmospheric moisture levels were probably at a record).
The full story
SOI in Rising Phase 08/02/06
Queensland's first tropical cyclone of the season was recorded late January. Unfortunately for those looking for it to cross the coast and bring rain to the interior it has moved to the east away from Queensland towards Vila and Noumea. For more information on cyclones go to the Bureau of Met tropical cyclone warning centre at www.bom.gov.au/weather/qld/
The key indicators of the SOI, trade winds and sea surface temperatures (SST) confirm the persistence of a neutral sea surface temperature and climate pattern in the Pacific (i.e. no El Niño). This pattern is unlikely to change before the end of summer.
However some features of a weak La Niña are present in the Pacific (namely cool SST in the eastern Pacific). There is the slight chance that with further cooling of ocean temperatures in the central and eastern Pacific, a La Niña-type situation may develop over coming months, which is rather unusual at this time of the year.
The monthly value of the SOI rose from minus 1.4 for December to plus 11.7 for January. Based on a "Rapidly Rising" SOI Phase at the end of January there is a 50 to 70% chance of getting above median rainfall across much of north west and central west Queensland during February to April. For the remainder of the state there is a 30 to 50% chance of getting above median rainfall.
It will be interesting to see if positive values can be maintained over coming months or if this is a continuation of the roller coaster ride the SOI has been on for the last 12 months. As stated regularly, for an overall widespread improvement in conditions right across the state, it would help if the SOI went into positive values for a few months at least.
The latest rainfall probability maps are at www.dpi.qld.gov.au/climate and daily updates on the SOI are available on (07) 46881439.
Throughout much of NSW, Victoria and the south east corner of South Australia there is a 20 to 40% chance of getting above median rainfall during February to April. Across the rest of Australia the chance of getting above median rainfall for February to April is between 40 to 70% depending on location. For more information on rainfall probabilities at your specific location refer to Rainman StreamFlow.
The MJO was evident across northern Australia in mid-January with the onset of the monsoon across northern Australia and some rain in southern Queensland although this was largely confined to eastern regions. Based on a timing of 40 to 50 days it would next be expected in late February to early March.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/
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 February to April in the following years; 2005, 2003, 2002, 1996, 1986, 1982, 1980, 1977, 1968, 1967, 1963, 1954, 1953 and 1940.
For example at Mitchell well below median rainfall for February to April in those years was recorded three times, close to median rainfall was recorded seven times and well above median rainfall was four times. Information on what rainfall patterns where like for February to April in those years can be found in Rainman StreamFlow.
As with any probability based forecast system it is important to consider the opposite aspect. For example, Cunnamulla has a 75% chance of getting above 40mm during February to April. This also means that there is a 25% chance of NOT getting the 40 mm during February to April. Another way of looking at this is that in around three quarters of years with the current SOI pattern, Cunnamulla has received at least 40 mm over February to April. Therefore in one quarter, Cunnamulla has gotten less than its normal 40 mm over February to April.
The annual Australian Climate Summary for 2005 is available at http://www.bom.gov.au/announcements/media_releases/climate/change/ Key points include 2005 was the warmest year in Australia since widespread reliable temperature observations became available in 1910; since 1979 all but 4 years have been warmer than average in Australia; January to March 2005 was the 2nd driest on record across Australia; globally 2005 was amongst the 4th warmest years since records commenced in 1861 etc.
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).
