Chance of more: 15%
Chance of more: 15%
Chance of above average tropical cyclone (TC) activity
|Region||Outlook summary||Long-term* average number of tropical cyclones*||Chance of more tropical cyclones|
|Western||Fewer than average||7||15%|
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 1969–2014, 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. The eastern tropical Pacific Ocean has been much warmer than average during this time, exceeding El Niño thresholds. The Southern Oscillation Index, a measure of the atmospheric component of ENSO, has been strongly negative through this period. Climate models suggest the El Niño is nearing its peak and will persist into early 2016. During an El Niño, tropical cyclone numbers in the western region of the South Pacific Ocean tend to be below average.
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.
Before a tropical cyclone forms it is difficult to predict its exact strength and path, including whether it will make landfall. Tropical cyclones which remain out to sea can still cause storm surges, gales and areas of heavy/flooding rainfall over land.
Even after a tropical cyclone has passed, or has decayed below tropical cyclone strength, significant flooding may occur. The impacts of flooding may be more widespread than the area impacted by the cyclones damaging winds..
During the cyclone season, ensure you are well informed of any warnings from local agencies and instructions from local emergency services authorities.
Pacific tropical cyclones portal tracks since 1969
This outlook is produced using statistical relationships between tropical cyclone numbers and two indicators: the Southern Oscillation Index (SOI) and the Niño3.4 sea surface temperature index (NINO3.4 SST). These indicators provide a measure of the strength of the atmospheric and oceanic state, respectively.
The July, August and September SOI and NINO3.4 values were used in making the South Pacific tropical cyclone season outlook.
|NINO3.4 SST||1.60 °C||2.07 °C||2.28 °C|
The current status of ENSO can be viewed via the Bureau's ENSO Wrap-up. During July–September 2015 the eastern tropical Pacific Ocean was much warmer than average, clearly exceeding El Niño thresholds. The Southern Oscillation Index, a measure of the atmospheric component of ENSO, has also been strongly negative through this period, indicating a significant El Niño event. Climate models suggest the 2015 El Niño will remain strong into early summer, and persist into early 2016. .
This Outlook provides general guidance for the South Pacific region. For specific guidance for an individual country, please contact their National Meteorological and Hydrologic Service.
Map showing South Pacific tropical cyclone outlook regions.
|Whole South Pacific region||5° S||40° S||142.5° E||120° W|
|Western region||5° S||40° S||142.5° E||165° E|
|Eastern region||5° S||40° S||165° E||120° W|
Model: Kuleshov, Y., L. Qi, R. Fawcett and D. Jones, 2009: Improving preparedness to natural hazards: Tropical cyclone prediction for the Southern Hemisphere, in Advances in Geosciences, 12 Ocean Science, (Ed. Gan, J.), World Scientific Publishing, Singapore, 127-143.
Data: Kuleshov, Y., R. Fawcett, L. Qi, B. Trewin, D. Jones, J. McBride and H. Ramsay, 2010: Trends in tropical cyclones in the South Indian Ocean and the South Pacific Ocean, Journal of Geophysical Research 115, D01101, doi:10.1029/2009JD012372.