SOI message 24th April 2001 The 30-day average of the SOI is +1.7 (on 24/04/01). The SOI has fluctuated markedly during April but on average has been dropping.
The averaged sea surface temperatures in key regions of the eastern equatorial Pacific Ocean during March were noticeably warmer than the long-term average. However, it is still too early to tell just how much further these climate indicators will change. They may steady or alternatively may continue to develop into an El Niño pattern during the next year.
Based on the behaviour of the SOI during February and March, the probabilities of receiving at least median April-May-June rainfall are between 40 and 60% for most of eastern Australia. Coastal regions south of Rockhampton and also the Central Highlands have between a 60 and 80% chance of getting at least median April-June rainfall.
Review of Climate Forecasts and Information Climate pattern and SOI 'phase'. Based on the latest values and trends of the SOI, the probabilities of receiving above-median rainfall over the April-May- June period is between 40 and 60% for much of Queensland, although there are exceptions.
Coastal regions along the eastern seaboard south of Rockhampton the south-east coast still have reasonably high probabilities (60-80%) of receiving higher than normal April-June rainfall. The Brisbane- Gympie area has somewhat higher probabilities (70- 80%). The northern half of the Cape York Peninsula also has reasonably high probabilities (60-70%) of exceeding normal (median) rainfall.
Apart from the high probabilities in coastal regions (ie east of the Divide) most of NSW, Victoria, and Tasmania have between a 40-60% chance of getting at least their median April-June total. The probabilities in South Western Australia are between 60 and 70%.
Note that a 70% probability of receiving the long- term median for a location also means there is a 30% probability of not receiving the median for that location. These probability values are simply statements of fact referring to the history of rainfall events for particular locations over the past 100 years.
The outlook for winter is dependent on whether or not an El Niño develops during the next 3 months.
Sea-surface temperatures (SSTs). Many general circulation models are suggesting that there is a potential for warming in the eastern equatorial Pacific Ocean over the next 3 to 6 months. We will watch the situation closely to determine any potential for El Niño development this autumn. Close monitoring of SST patterns and the SOI over the next few months is suggested.
There has been warming of SSTs in the far eastern equatorial Pacific Ocean during March; however, it is too early to tell if this will continue to develop into something significant such as an El Niño.
Pasture Growth forecasts. The probabilities of obtaining median pasture growth or better during the April-May-June period are very patchy across the state. In the north and in coastal regions there are mostly low probabilities (10%) of 'above-average' growth. However, probabilities are higher (between 50 and 70%) in central and western districts .
30 to 50-Day Oscillation. The 30-50 day oscillation is next due to influence Queensland around the 3rd/4th week of April.