THE sea surface temperatures (SST) across the eastern tropical Pacific Ocean remains consistent with a developing El Niño event, although the confidence level of this developing has decreased a little in the past couple of weeks mainly due to a continued positive in the Southern Oscillation Index (SOI) and to the local area SST.
Subscribe now for unlimited access to all our agricultural news
across the nation
or signup to continue reading
The extent of this El Niño's effects on south-eastern Australian weather outcomes in the second half of 2014 look as though they will be moderated a little by this relatively warm water around the Australian region, compared to previous El Niño events.
The north-eastern Indian Ocean SST patterns will be a critical factor in this and their predictability is often challenging at the best of times.
If they stay a little warmer than normal, then the Indian Ocean Dipole will remain aabout zero and the chance of at least an occasional rain event over inland NSW from moisture sourced from the Indian Ocean will remain reasonable.
Although the words El Niño are associated with drought, this is perhaps a little unfair.
It is true that the majority of these events are associated with reduced rainfall but this is not the case in approximately one third (30 per cent) of them and the initial signs developing at the moment would point to the likelihood that this event will be one of those 30pc.
A greater majority of El Niño events are associated with above average temperatures and with the SST staying up, the looks more likely.
The chance of above average seasonal temperatures in spring and next summer are more than 90pc for much of NSW.
The longer term trends are unclear.
The El Niño event is still favoured to persist into 2015 and the longer it lasts, the greater chance there is of the Indian Ocean a temperature falling in which case the chances of a drier than normal autumn in 2015 would increase.
Contact Don White, Weatherwatch, (02) 9451 7102 or fax (02) 9975 1608.
