Quote:
Originally Posted by adman
Hmm - wettest year on record....
Is it tempting fate then to say that this year has to be better......?
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Hi Adam,
The good news for observers is that predictions by the Bureau
"indicate the (La Niña) event will gradually weaken, approaching neutral values by mid 2011."
According to the El Niño Southern Oscillation (ENSO) report issued yesterday -
Quote:
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Originally Posted by BOM
A major La Niña event continues to affect the Pacific Basin. Long-range forecast models surveyed by the Bureau suggest that the La Niña is likely to persist into the southern hemisphere autumn.
All climate indicators of ENSO remain beyond La Niña thresholds.
...
The Southern Oscillation Index (SOI) value for December of +27 is the highest December SOI value on record, as well as being the highest value for any month since November 1973.
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Quote:
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Originally Posted by BOM
The influence of the Indian Ocean Dipole (IOD) on Australian rainfall is limited during the months from December through to April.
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Some background on the IOD here -
http://www.bom.gov.au/climate/IOD/about_IOD.shtml and here -
http://en.wikipedia.org/wiki/Indian_Ocean_Dipole
Quote:
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Originally Posted by BOM
The national outlook for the January to March period favours wetter conditions in the eastern half of NSW, southeastern Queensland and western WA.
The pattern of seasonal rainfall odds across Australia is a result of cool conditions in the central equatorial Pacific Ocean associated with the current La Niña.
The chances of receiving above median rainfall during the January to March period are between 60 and 70% across the eastern half of NSW, southeastern Queensland and western WA. Such odds mean that for every ten years with similar ocean patterns to those currently observed, about six to seven years would be expected to be wetter than average over these areas, while about three to four years would be expected to be drier during this January to March period.
In contrast, the outlook favours drier conditions in southwestern Queensland and northeastern SA with odds of exceeding the median rainfall below 40%, indicating an increased risk of drier conditions in these areas. However, this outlook should be used with caution in this area due to the low confidence levels.
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Looking into the Super Computer crystal ball ...
Quote:
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Originally Posted by BOM
All leading international climate models surveyed by the Bureau predict surface temperatures in the tropical Pacific Ocean will remain at levels typical of a La Niña event throughout the first quarter of 2011. The majority of models surveyed indicate the event will gradually weaken, approaching neutral values by mid 2011.
Recent forecasts from the POAMA model, run daily at the Bureau of Meteorology, predict La Niña conditions will persist during the first quarter of 2011, but will gradually weaken with time as the central Pacific warms.
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Full report here -
http://www.bom.gov.au/climate/enso/