Australian tropical cyclone season outlook
The video includes season forecasts for:
- Tropical cyclones
- Severe storms
- Damaging winds
About tropical cyclones
See also:Pacific outlook Tropical cyclone warnings
About the outlooks
This outlook uses the statistical relationships between tropical cyclone numbers and two indicators: the Southern Oscillation Index (SOI) and the Niño3.4 sea surface temperature anomaly. These two indicators provide a measure of the atmospheric and oceanic state, respectively, of El Niño-Southern Oscillation (ENSO).
The July, August and September SOI and NINO3.4 values were used in making the tropical cyclone season outlook.
Interpreting the outlook
Percentages such as a 60% chance of having more tropical cyclones than average (or a 40% chance of having fewer) mean that for every ten years with similar climate patterns to those currently observed, six years would be expected to have an above-average number of tropical cyclones and four years would be expected to have a below-average number.
The long-term average number of tropical cyclones per season in the Australian region (since 1969–70) is eleven, with four typically making landfall. Since the year 2000, there have been an average of nine tropical cyclones in the Australian region each season.
During El Niño events, there are typically less tropical cyclones than average, while more tend to occur during La Niña events. As always, it is essential that all local communities prepare for the cyclone season regardless of the outlook.
Australian region outlook accuracy
Over the entire Australian Region, this statistical relationship has proven to be highly accurate, or a skilful way to forecast tropical cyclone activity. However, across the sub-regions this relationship, and thus forecast skill, can vary. Some regions have much higher forecast skill than others. The Northwestern sub-region has good skill, while the Western and Eastern regions both have low skill and the Northern region has very low skill.
Australian tropical cyclone outlook region bounds
|Australian region||5° S||40° S||90° E||160° E|
|Western region||5° S||40° S||90° E||125° E|
|NW sub-region||5° S||25° S||105° E||130° E|
|Northern region||5° S||40° S||125° E||142.5° E|
|Eastern region||5° S||40° S||142.5° E||160° E|
- Tropical Climate Update
- Southern Oscillation Index (SOI)
- Niño3.4 sea surface temperature index (NINO3.4 SST)
- Tropical cyclone climatology maps
Model: Kuleshov, Y., L. Qi, R. Fawcett and D. Jones, 2008: 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.
An above-average number of tropical cyclones is likely for Australia in 2022–23
- It is likely there will be an above-average number of tropical cyclones for the 2022–23 Australian tropical cyclone season (November–April).
- Since Australian records began in 1969–70, the average number of tropical cyclones that form in a season in the Australian region is 11, four of which typically cross the coast.
- The established La Niña in the tropical Pacific Ocean and warmer-than-average sea surface temperatures to the north of Australia, have influenced this year's tropical cyclone outlook.
- In La Niña years, the first cyclone to make landfall on the Australian coast typically occurs earlier than normal, around the middle of December. During average years, the date of the first tropical cyclone to make landfall over Australia is typically in early January.
- At least one tropical cyclone has crossed the Australian coastline in every season since reliable records began in the 1970s.
- Cyclone formation is rarely spread evenly throughout the season; often quiet periods are followed by bursts of activity.
- Tropical lows that do not intensify into cyclones, or lows that are the remnants of older cyclones, can still produce damaging winds, widespread rainfall, and dangerous flooding. These impacts can extend beyond the tropics into southern areas of the country.
- Like tropical cyclones, the number of tropical lows that form during La Niña years is typically greater than the number which form during non-La Niña years. From the 2005–06 season onwards, the typical number of tropical lows has been 7 for all years, and 10 for La Niña years.
This outlook is based on the status of the El Niño–Southern Oscillation (ENSO) over the preceding July to September. La Niña was fully established in the tropical Pacific in September 2022, the third La Niña in successive years. Climate models suggest ENSO will return to neutral conditions in early 2023.
Ocean temperatures to the north of the country, especially in the Coral Sea are currently warmer than average. Climate models predict warmer than average waters are likely to persist to the north of Australia for the coming 3 months, marginally increasing the likelihood of tropical cyclones developing.
Tropical cyclone activity in the Australian region has large variability from year to year, due to the influence of naturally occurring climate drivers, such as ENSO. The number of tropical cyclones in the Australian region is generally higher with La Niña. In recent decades, the annual number of tropical cyclones that form in the Australian Region has decreased, from an average of 11 across all seasons since Australian records began in 1969–70, to 9 for the period since 2000–01.
Outlook by region
For 2022–23, the outlook indicates that an above-average number of tropical cyclones is likely in all but the Northern region.
- The Australian region has a 73% chance of having more tropical cyclones than average. This is also equivalent to a 27% chance of fewer tropical cyclones than average. Typically, 11 tropical cyclones form or pass through the Australian region in a season, with around four of these crossing the Australian coast. Outlook accuracy for the Australian region is high.
- The Western region has a 69% chance of having more tropical cyclones than average. Typically, at least 1 tropical cyclone in the Western region will create coastal impacts, regardless of how many make landfall. The average number of tropical cyclones to form in or pass through the Western region is 7 each season. Outlook accuracy for the Western region is moderate.
- The Northwestern sub-region has a 70% chance of more tropical cyclones than average. Typically, 5 cyclones form in or pass through this area each season. Around 3 tropical systems (tropical cyclones, or their associated tropical lows) are expected to affect coastal areas of the Northwestern sub-region. Outlook accuracy for this region is moderate.
- The Northern region has a 61% chance of more tropical cyclones than average. Typically, the Northern region experiences 2 or 3 cyclones each season. About three-quarters of the tropical cyclones in the Northern region have some form of impact upon coastal regions. Outlook accuracy for this region is low.
- The Eastern region has a 74% chance of more tropical cyclones than average. The average number of tropical cyclones for this region is 4, and around one of these make landfall. Outlook accuracy for this region is moderate.
The tropical cyclone season typically runs from 1 November to 30 April, although tropical cyclones can and do form outside of those bounds. All tropical cyclones existing between 1 July and 30 June the following year count towards the season total. The broader Australian region covers the area south of the Equator and between 90°E and 160°E, and includes Australian, Papua New Guinea, and Indonesian areas of responsibility.
Product code: IDCKAUTCSO
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