South Pacific tropical cyclone season outlook

The tropical cyclone season runs from 1 November to 30 April

More cyclones than average likely in the western Pacific Ocean

  • Neutral to weak La Niña conditions in the tropical Pacific Ocean increases the odds of above-average number of tropical cyclones for the western South Pacific region.
  • Climate models indicate that neutral conditions are likely to persist into 2017.
  • Near-average cyclone numbers are likely for the eastern South Pacific but model accuracy is very low

The South Pacific tropical cyclone season has most cyclones between 1 November and 30 April and averages around seven tropical cyclones in the western region and ten in the eastern region. Tropical cyclones impact Pacific island countries in most years and coastal impacts can still be felt when tropical cyclones remain well offshore.

* Long-term average number of tropical cyclones, calculated using data from 1969–2015, may change slightly from one year to the next as a new season of data is added to the calculation.

This outlook is based upon the status of the El Niño–Southern Oscillation (ENSO) during the preceding July to September period. Eastern tropical Pacific Ocean sea surface temperatures were slightly cooler than average during this time but within neutral thresholds. The Southern Oscillation Index, a measure of the atmospheric component of ENSO, has been positive through this period and has recently exceeded La Niña levels. Climate models suggest that neutral conditions will persist into early 2016. Nevertheless, warmer than average sea surface temperatures in the western Pacific ocean are favourable for tropical cyclone development. This increases the chances of an above-average number tropical cyclones forming in the western region of the South Pacific Ocean.

The statistical model used for this outlook has a high level of accuracy predicting cyclone numbers in the western region, but a very low level of accuracy for the eastern region. This outlook is for the southern hemisphere tropical cyclone season which runs between 1 November and 30 April.

 

Product code: IDCKSPTCSO