Cyclone chances above average for 2011-12


Bureau of Meterology's Australian Region forecast based on 'neutral to borderline La Niña conditions'

By Rob McKay | October 18, 2011

Transport operators impacted by Cyclone Yasi, and even those who weren’t, may do well to revisit the lessons learnt in the light of the Bureau of Meterology’s 2011-12 AustralianTropical Cyclone Season Outlook.

The whole Australian region has an 80 per cent chance of having more than the long-term average number of cyclones.

The long-term average is 12.

"This outlook is based upon the status of the El Niño-Southern Oscillation (ENSO) over the preceding July to September period," the Bureau says.

"During this period in 2011, neutral to borderline La Niña conditions were present.

"Historically, these conditions have favoured an above average number of cyclones in the Australian region."

The Bureau divides the Australian Region into three - Eastern, Northern and Western - on north-south lines roughly corresponding with the Northern Territory's borders.

It also has a forecast for the "North-western Sub-region", roughly north and east of Geraldton and south and west of Darwin.

The outlook for particular regions is 60-65 per cent.

The Bureau rates its "forecast skill" level for the Australian region as "very high", while that for the regions within it is rated as "moderate".

For the Eastern Region, which bore the brunt of Cyclone Yasi, a 65 per cent chance is forecast that it will experience a higher than average number of tropical cyclones.

On a slightly brighter note, the regions include a great deal of sea area and about 25 per cent of the tropical cyclones in the Eastern region cross the coast.

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