Will the MJO produce some relief rain? (12/11/03)
As dry conditions continue across most of Queensland the big question remains as to when will conditions improve. Our next best opportunity for some 'climate induced' rainfall should be over the next week when the MJO (40 day wave) is due to influence our weather.
The MJO is simply a band of low atmospheric pressure originating off the east coast of central Africa travelling eastward across the Indian Ocean and northern Australia roughly every 30 to 50 days.
While it is a tropical phenomenon, it appears to indicate the timing of potential rainfall events (but unfortunately not rainfall amounts) over much of Queensland.
The last passage of the MJO influenced our weather in the first week of October producing some very patchy but useful rainfall totals especially across the south east quarter of Queensland.
The Queensland DPI/APSRU is undertaking further GRDC funded research into the influence of the MJO.
The 30day average of the SOI as of the 12th November is minus 2.2. It is interesting that the SOI hasn't been in a 'Consistently Positive' phase since March 2001.
Currently there is a 50-60% chance of getting above the long term November to January median rainfall across eastern Queensland. Rainfall probabilities are marginally higher reaching 60-70% for parts of the north and central coastal strip. Gayndah, for example has a 61% chance of getting above its long term November to January median rainfall of 290mm.
For the rest of Queensland though, the chance of getting above median rainfall is lower at 40-50%.
Key indicators in the Pacific such as near-surface level wind anomalies and sub-surface sea temperatures now show potential for the emergence of 'near El Niño' conditions over the next 3 to 8 months. US coupled and other ocean/atmosphere models also suggest continued warming towards 'El Niño-like' conditions for 2004/2005.
While it is too early to be definitive regarding climate conditions in 2004/2005 I suggest particularly close monitoring of key climate indicators (sea-surface and sub-surface temperatures, SOI, near-surface wind anomalies) and climate model outputs over the next 3 to 6 months.
For more information refer to AUSTRALIAN RAINMAN or contact me through the DPI Call Centre on 13 25 23.