DURING the past month, warm water continued to build across the eastern half of the Equatorial Pacific Ocean which helped to continue the weakening of the La Nina event.
However there still remains large areas of the central to eastern Pacific Ocean that are experiencing below average sea surface temperatures, while a large region of the western Pacific remains warmer than normal which is therefore quite "La Nina like" in the ocean temperature patterns and it is well placed to swing back to full La Nina conditions during spring.
Some models put this at around a 65 per cent (two out of three) chance, which is quite significant.
In addition, there is a pool of cold water below the surface in the central Pacific Ocean and it is likely to shift eastwards in the coming one to two months and then cool the waters in the eastern Pacific Ocean once again.
So based on this forecast as well, it also points to an increasing threat of a La Nina redeveloping for late spring and summer, resulting in a rare triple La Nina event.
In addition, stronger than usual easterly trade winds have continued across much of the western Pacific this winter (which is a pattern typical of a La Nina event).
It also points to a higher potential for moisture to push in from the Pacific Ocean along the east coast as we move towards spring.
Spring is also the time when the negative Indian Ocean Dipole can support increased rainfall over eastern and south east Australia. Most models suggest the negative "peak IOD" is unlikely to occur until September/October (which will also potentially be the time that we see the Pacific Ocean trend back towards a full La Nina).
IN OTHER NEWS:
The result is likely to be a wetter than usual spring. August is also likely to be similar, though higher positive rainfall anomalies may exist during September and October.
Strong negative IODs typically correlate with an earlier start to the storm season but these are favoured to be less severe overall due to the higher level of cloud cover occurring
The last time we saw a strong negative IOD occur with a La Nina was during the 2010-11 period when large areas experienced above average rainfall.
Temperature outlooks in these conditions are always challenging.
There is already above average temperatures building across northern and north west Australia.
Rapid warming of these areas normally correlates with above average maximums during spring, but the expected increased cloud cover and rainfall will most likely offset this and result in closer to average (and potentially slightly below average) maximums over the coming months.
