Outlook heads back to neutral

In addition, the outlook is for nothing much to happen in the coming months with a neutral pattern expected to persist for at least five to six months.

Most indicators are now within the neutral range.

Sea surface temperatures remain within the neutral range and in the atmosphere, trade winds in the tropical western Pacific and cloudiness patterns near the International Date line are near normal, consistent with a neutral state.

The 30-day Southern Oscillation Index (SOI) is back into the “La Nina” range above +7 but it is showing a fair bit of variability as well, due to the presence of tropical cyclones in the Australian region in recent weeks.

Neutral patterns do not always mean neutral rainfall patterns but variable ones with the dependence on one off events more important than usual.

It has meant in the past, that the chance of widespread and significant rain events decreases and a continuation of the pattern of recent weeks with the occasional major rain event affecting just a few areas and many others missing out.

With sea surface temperatures around continental Australia remaining above normal, it is likely that temperatures for the rest of autumn and early winter will remain a little up on normal.

However, as indicated previously, the occasional brief cold spell will become more frequent as we head towards winter.

This variability in temperature as well as rainfall is favoured to persist through most of winter in eastern Australia.

After that, things become more speculative.

The chance of an “El Nino” returning by later in the year slowly increases in spring but the probability of neutral conditions remain greater than the probability of an “El Nino” through until October and even after that the chances of an “El Nino” remains less than 50% until the end of the year.

However, the chances of longer periods of stability in spring are fairly strong.