DESPITE seeing some signs for optimism along with some good rains in many parts of eastern Australia in the past six weeks, there remain a few worrying signs that would imply everything is not back to normal and follow-up rains so desperately needed may be a little "hit and miss" in the coming months.
As indicated previously, all of the medium and longer term indicators remain neutral and are not giving off clear indications as to what direction they might take in autumn and winter this year.
All of the El Nino-Southern Oscillation indicators, such as the strength of the south-east trade winds, cloud amounts near the International Date Line, most of the sea surface temperatures in the tropical and western Pacific and the Southern Oscillation Index are all at neutral levels.
However the SOI remains around -2 so although in the neutral range, it is below the mean (on the dry side) of that range. Stability in the tropics has helped it stay a little down.
To the west in the Indian Ocean the Indian Ocean Dipole is also neutral even though it rarely influences our weather before later in April.
However, long-term models that look at the IOD differ considerably as to what it will do in the months after April, when its influence on our rainfall potential will be greater.
If it happens to return to the positive, then this would reduce winter rainfall potential but at the moment, models are divided on whether this will happen or not.
However, it introduces a greater level of uncertainty into any outlook.
On the more positive side of things the sea surface temperatures remain up on normal around most of continental Australia.
Apart from assuring higher than average winter temperatures for the majority of the time, it also could provide a boost to moisture when the synoptic patterns favour onshore winds.
Again this could provide some occasional one-off rain events - something we are going to have to depend on over the coming months.
As the climate changes and the world gets warmer, greater variability will also be an issue.
In the second half of autumn and early winter, the occasional but significant cold outbreak is likely to be a feature and such events could also occur when a one-off rain event develops in the eastern states - but this is only likely on very few occasions in the coming months.
