Chance of more: 39%
The South Pacific tropical cyclone season:
Chance of more: 39%
Chance of above average tropical cyclone (TC) activity
(near, below or above
number of tropical cyclones*
|South Pacific||Near average||55%||14|
*The long-term average number of tropical cyclones may change slightly from one year to the next as a new season of data is added to the calculation. The average number of tropical cyclones for the western and eastern region add to more than the average for the South Pacific, as cyclones that develop in one region and cross the border are counted twice when averages are added.
This outlook is based upon the status of the El Niño—Southern Oscillation (ENSO) over the preceding July to September period. Whilst the Pacific Ocean has remained neutral during these months, ocean temperatures have been near El Niño thresholds. The Southern Oscillation Index, the measure of the atmospheric component of ENSO, has been negative through this period. Climate models suggest there is still double the normal chance of El Niño occurring this summer (i.e. 50% chance). During an El Niño, tropical cyclone numbers in the Western Region of the South Pacific tend to be below average.
The model has a good level of accuracy predicting cyclone numbers in the western region, a very low level of accuracy for the eastern region and a low level of accuracy for the South Pacific region.
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.
The current status of ENSO can be viewed via the Bureau's ENSO Wrap-up. Tropical Pacific Ocean temperatures have been in a neutral state since October 2012. This means that the sea surface temperature patterns in the Pacific are neither La Niña nor El Niño and is therefore not driving the South Pacific region toward significantly more or fewer tropical cyclones than average. As such, the forecast is suggesting a season closer to average.
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.