THE summer La Nina appears to have concluded and conditions are neutral already with most indicators now pointing to neutral conditions across the Pacific basin for some months.
However, as indicated previously, the chance of above average autumn and winter rainfall in eastern and south eastern Australia is still fairly good but it has decreased somewhat with the fairly quick demise of the La Nina event.
From now on this will be dependent on occasional significant events, interspersed by extended periods of stability, one of which we are in at the moment.
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Although the La Nina event as far as ocean sea surface temperature patterns are concerned has been on the wane for some weeks, the atmospheric response has been a little quicker than expected.
The Southern Oscillation Index is back to near zero, while trade winds in the tropical western Pacific are also normal.
Stable weather for the rest of April is a little more likely now that the Madden-Julien surge of tropical activity has moved away, marking the probable end to the wet season in the tropics until next October.
Our attention now moves to the west.
The Indian Ocean Dipole continues to be close to zero although it has briefly edged to weakly positive in the past week or two. Most models still indicate a slight decrease in the IOD in the coming month, which would be important as even a very weak negative IOD can be a positive in the development of the so called north west cloud bands on which late autumn and early winter rains in south east Australia depend on to some extent.
One positive feature in the Indian Ocean remains the slightly above average sea surface temperatures in the north east tropical parts of the ocean off the north west coast of Australia.
Even with the IOD near zero, this warmer water can help generate convective activity which leads to the north west cloud bands.
Because of the excess of cloud in northern and eastern Australia in summer and last month, temperatures are a little lower than they have been for a few years.
Clear skies will result in cooler than average nights in the coming weeks, with a slightly increased chance of early season frosts, especially in areas susceptible to such conditions.
Previously I have mentioned greater variability as a developing feature of the climate in the coming years.
Early season significant cold spells - although brief - are slightly more likely than usual this year and they can set up conditions for a good snow year in the Australian Alps, which is of interest to irrigators and skiers alike.
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