SOI message 20th December 2000 (to be updated on 3rd January 2001)
The average SOI over the previous 30 days remains ' strongly' positive at +16.9 (up to 20th December). The impact of a high SOI value on rainfall varies across the state. The probabilities of getting or exceeding the long-term median rainfall during the total December-February period are now 60-80% in most of eastern Queensland. Parts of southern Qld and the central-west have comparatively low probabilities at about 50%.
Climate pattern and SOI 'phase'. Our forecasts indicate the chances of useful rain through mid- summer for most regions in eastern Queensland are relatively high. Our latest map shows the probability of receiving median rainfall for most of eastern Queensland is between 60-70% with some notable regions in the far north and around the eastern Burnett with even higher probability values (70%-80%). However, much of the Darling Downs and some scattered western regions now have just about a 50-50 chance of getting their long-term median rainfall for the core summer months. 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. Sea-surface temperatures (SSTs). Since June we have primarily been in a "neutral" climate pattern. However over the past few months SSTs have cooled in some key regions of the eastern equatorial Pacific Ocean. This has created a pattern resembling a La Niña pattern.
Temperatures of waters off the coasts of eastern Qld and northern NSW are around average.
Some general circulation models are suggesting the potential for warming in the eastern equatorial Pacific Ocean over the next 6-9 months. We will watch the situation closely to determine any potential for El Niño development, or otherwise, in 2001. Close monitoring of sea-surface temperature patterns over the next six months is suggested.
Pasture Growth forecasts. The probabilities of obtaining median pasture growth or better during the October to December period are 'above-average' over most of Qld. However notable exceptions are parts of the south-east of the State where the probabilities are only 10% to 30% due to poor soil moisture conditions.
30 to 50-Day Oscillation. The next passage of the 30 to 50-Day Oscillation over Qld is expected around Christmas time.
More detailed information for your location can be obtained from the Australian Rainman software package.