The decaying Pacific basin El Nino and the maintaining of warmer than normal sea surface temperatures around much of the Australian continent, especially off the east coast, means that temperatures will remain above normal for many months to come but it also means that the chance of drought conditions has faded away. Rainfall is likely to be variable but slightly above normal overall, but the confidence level of any rainfall prediction is lower than the confidence level of temperature predictions.
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For a start, increased levels of moisture often mean the potential for warmer than average minimum temperatures to occur (particularly across eastern NSW and eastern Queensland) in response to the increased potential for higher humidity and cloud cover. As we head into late autumn that also means a slightly decreased frost risk is likely. However, the developing pattern means the closer we get to winter, the greater the chance of a brief burst of cold air. Such an occurrence can see one or two days of significant temperature drops over south east Australia and eastern Queensland during a period of generally above average temperatures and briefly increase frost potential in the ranges.
Above average maximum temperatures are still likely to occur on the majority of days throughout winter as well but may trend closer to average in late July and August.
Overall, however, the long-term climate indicators have not changed in the past couple of weeks. The El Nino patterns in the Pacific Ocean have continued to weaken and in the sub-surface of the tropical Pacific Ocean, an increasingly large cold pool of water continues to track eastwards and is expected to upwell across the eastern Pacific in the coming months, leading to a decrease in SSTs in that region, which in turn is favoured to result in a La Nina pattern developing, which could occur as early as late winter / early spring. A La Nina event often but not always correlates with an increase in rainfall over Queensland, NSW and northern Victoria.
The Indian Ocean remains in a neutral phase which is expected to persist for some months, so this means that it is unlikely to be much influence at all for a while. The same applies to the Madden-Julian Oscillation to the north, which usually has minimal effect from late April to November.
So, in summary, it is likely that there will be at least average rainfall over the next six months in most of the eastern states, but there will be some variability with dry spells becoming a little longer in the east and south. It also means generally above average temperatures but once again, variability will be the occasional feature.
