El Nino Breaks Down Dave McRae 01/03/07
In the latest El Nino wrap-up available at www.bom.gov.au the Bureau of Meteorology states that along the equator, sea-surface temperatures are cooling rapidly and now below their El Niño thresholds, trade winds since December have mostly been close to or somewhat stronger than normal, the SOI has been neutral for three of the past four months and central-western Pacific cloudiness is close to average.
While the end of the El Nino would normally be associated with a return to more normal rainfall pattern, it should not be seen as a start to drought-breaking rains. This particularly applies to eastern and southern Australia, which in some instances will require several years of good rainfall to recover.
However we can be optimistic that there will be a general easing of dry conditions in drought affected areas. This may not be an issue for the recently wetter parts of north Queensland but will hopefully bring more than just relief rain to southern and central Queensland.
As autumn is a key time for the establishment of climate phenomena such as El Nino and La Nina DPI&F climate staff will continue to closely monitor what happens over the next few months. In terms of a state wide improvement in seasonal conditions a year of consistently positive SOI values and a La Nina (and maybe a bit of luck) would help.
Despite the rise in SOI values from January through to the end of February the SOI is still is a "Consistently Negative" SOI phase. An analysis of historical rainfall records and a Consistently Negative SOI phase indicates a 30 to 50% of getting median rainfall throughout the northern half of Queensland and a 40 to 60 and in a few locations 70% chance of getting median rainfall throughout southern Queensland for March through to the end of May.