2011–2012 Australian tropical cyclone season outlook

Above average tropical cyclone activity likely for the Australian region this season

The outlook favours the following scenarios for the coming season:

  • The whole Australian Region has an 80% chance of having more than the long-term average number of cyclones. The long-term average is twelve.
  • The Western Region has a 65% chance of observing above average number of tropical cyclones, where the long-term average is seven.
  • The North-western Sub-region has a 60% chance of above average number of tropical cyclones. The long-term average is five.
  • The Northern Region has a 60% chance of above average number of tropical cyclones, where the long-term average is two or three cyclones.
  • The Eastern Region has a 65% chance of observing above average number of tropical cyclones, where the long-term average is three or four.
The tropical cyclone Australian regions

Figure 1 The regions defined for this tropical cyclone outlook with the average number of cyclones per season for each region and the forecast chance of that region having above average TC activity in the 2011-12 season.

Seasonal outlook for tropical cyclones

Tropical cyclone activity in the Australian region (5°S-40°S, 90°E-160°E) is likely to be above average this coming season. The outlook suggests a 80% chance of having more than the long-term average number of cyclones in the Australian region during the 2011-12 season. (For more info about average tropical cyclone activity and La Niña events see info about Tropical cyclone average conditions.)

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

Region Chance of
above average
Long-term average
number of TCs*
Forecast
skill
Australian region 80% 12 Very high
Western region 65% 7 Moderate
North-western sub-region 60% 5 Moderate
Eastern region 65% 4 Moderate
Northern region 60% 3 Low

Regional features

  • The outlook for the Western Region suggests a 65% chance of the total number of tropical cyclones being above average (35% chance of being below average). In the past, the skill level for forecasts in the Western Region is moderate. On average, around 30% of tropical cyclones in the western region will have an impact on the coast at some stage in their life.
  • The North-western Sub-region (the area from 105°E to 130°E, where tropical cyclones can impact upon coastal WA communities) has around a 60% chance of experiencing more tropical cyclones (40% chance of receiving fewer) than its long-term average. On average, around 40% of tropical cyclones in the north-western sub-region will have an impact on the coast at some stage in their life.
  • For the Northern Region, the outlook is a 60% chance of an above average number of tropical cyclones, although the skill level for this outlook is low. In an average year the Northern region sees two or three named storms and one or two tropical low pressure systems that become cyclones after moving into the Western or Eastern regions. A relatively high number (75%) of tropical cyclones in the northern region cross the coast at some stage in their life.
  • The Eastern Region has a 65% chance that it will experience a higher than average number of tropical cyclones (35% chance of fewer than average), with a moderate confidence level based upon historical skill. Around 25% of the tropical cyclones in the Eastern region cross the coast.

This outlook covers the Australian tropical cyclone season which is considered to be between 1 November and 30 April.

Past Australian tropical cyclone season outlooks