Climate pattern volatile
GroundCover™ Issue: 33
The SOI remains in a consistently positive phase despite the monthly SOI value for December falling to +7.7 from November's +20.6.
Based on the latest values and trends of the SOI and historical rainfall data, the probabilities of receiving above-median rainfall over the January to March period are relatively high (50-80 per cent) for many parts of Queensland, New South Wales and the western half of Western Australia. As always, remember that the opposite also applies and that in this case there is around a 30-50 per cent chance of getting less than the median rainfall for the January to March period.
Much of South Australia, Victoria and Tasmania has only relatively low probabilities of between 20-50 per cent of getting more than the median rainfall for the next three months. This is a good example of how a consistently positive SOI phase does not equal high rainfall probabilities at all locations.
New story after March
It would be very risky to extrapolate this outlook past the end of March. Ongoing changes in sub-surface sea temperatures and SOI trends strongly indicate a shift in the SOI phase during the crucial May-June period similar to what happened in 1991. As a result, for activities planned for later this year (2001 winter, spring, summer), keep a close track of these SST and SOI developments.
Get the most up-to-date specific outlook for your area by trying the Internet site www.dpi.qld.gov.au or by using the AUSTRALIAN RAINMAN CD package. QCCA has a free 'Weekly Climate E-mail' that is sent out to subscribers. If you are interested in receiving this weekly e-mail or are after some more climate-related information, call 07 4688 1459.