SOI Update (Dated 12/03/03)
The 30day average of the SOI as of the 12 th March is minus 5.4. Based on the shift in monthly SOI value from the end of January (minus 2) to the end of February (minus 9.3) the SOI is in a "Rapidly Falling" phase.
This gives a somewhat mixed seasonal outlook across Queensland for March to May. For the Queensland/New South Wales border region west of Goondiwindi there has been a slight lift in the chance of getting above median rainfall to around 50-70%. However for the rest of the state the chance of above median rainfall for the same period has fallen slightly to around 20-40%.
As readers would be aware, an El Nino sea temperature pattern has been the dominant feature of the Australian climate over the last 9 to 12 months. The 2002/03 El Nino event will be remembered for it's negative impact not only on rainfall patterns but also on expected crop yields and animal production Australia wide.
The El Nino pattern can still be found in the central Pacific Ocean. Warm sea temperature anomalies of around +0.9 to +1.5Â°C can still be found in the Nino 3 and 4 regions (along the equator running eastward from the international dateline). Based on changes in both the atmosphere and Pacific Ocean there is increasing optimism that this pattern is starting to break down. While this is good news, it's worth remembering that there remains a chance of El Nino regeneration in some form past autumn.
It's worth pointing out that even if this pattern breaks down at the end of autumn, conditions may not improve in all areas for several months as unfortunately the breakdown of major drought events rarely occurs evenly across all affected areas.
Previous El Nino events include autumn 1902 to autumn 1903, 1905/06, 1911/12, 1913/14, 1914/15, 1919/20, 1925/26, 1940/41, 1941/42, 1946/47, 1951/52, 1957/58, 1964/65, 1965/66, 1969/70, 1972/73, 1977/78, 1982/83, 1987/88, 1991/92, 1993/94, 1994/95 and 1997/98. For planning purposes it may be helpful to find out when conditions improved in your area following these events?
In many areas, the winters following an El Nino event are the best chance for average to above winter rain and potential high winter crop yields. Some years that were examples of this include 1978, 1983, 1988, and 1998 (although 1998 was actually too wet in many areas with resultant crop diseases).
Autumn 1992 is a good example of a partial breakdown in an El Nino pattern with it then reforming in early winter (not necessarily as a classic El Nino but something close to it). Some relief rain followed by a fairly dry winter usually characterizes this type of pattern. These types of years are comparatively rare but include 1992, 1993, 1994, 1940, 1941, 1912, 1913, 1914, and 1915.
For the latest and most up to date information on the seasonal outlook for your location try the "Climate Note" at www.dpi.qld.gov.au/climate