El Nino uncertainty remains

El Nino uncertainty remains


Only five out of the eight major international models are predicting an El Niño to develop this year.


ONE of the features of the weather charts during the past six months has been the frequent stagnation of the surface and upper synoptic weather patterns. 

This stagnation has resulted in extended periods of stable weather over large areas of the state and only interspersed by occasional bursts of instability. 

It has been a contributing factor to the well below average rainfall over large parts of NSW, southern Queensland and agricultural South Australia. 

Strong Southern Ocean fronts have moved things along a little at times in the last month or so and this has helped bring scattered rain events, mainly in the south and more recently in the north-east inland, but these features are random and infrequent and there are no indications that this is likely to change in the immediate future. 

As a result, the most likely scenario is for a continuation of below average rainfall overall but locally, the one off, occasional rain events will have the potential to bring at least average monthly rainfalls to some areas. 

However, it remains unlikely that such events will be widespread, so moisture deficiencies will persist in many parts of central and northern NSW into spring. 

Unfortunately, the spring outlook is influenced by a potential El Nino event developing. 

Such events more often than not bring below average spring and early summer rainfalls to NSW but not always. 

They can also be responsible be for above average temperatures in spring and summer and an increased potential for localised severe storms. 

However, it is not all pessimistic. For a start only five out of the eight major international models are predicting an El Niño to develop this year – so it is by no means certain. 

In addition, the Indian Ocean Dipole remains slightly negative and is favoured to remain near zero for some months and this will at least slightly increase the chance of those one off events bringing occasional rain in places. 

That is what we have to hope for. 


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