Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) outlook for July to September and July to October 2022 is indicating above 60 % probability of above median rainfall for the majority of the South West Land Division.
- For July to September, the SSF forecast is indicating above 60% probability of above median rainfall for parts of the Central West, Central Wheatbelt, Lower West, South West and South East Coastal forecast districts, with neutral (40-60%) probability for the remainder. The most likely decile range map is indicating decile 8-9 for parts of the Central West, Central Wheatbelt, Lower West, South West and South East Coastal forecast districts, decile 2-3 for part of the South Coastal forecast district and decile 4-7 elsewhere. Skill is poor to good at 50 to 70% consistent.
- The Bureau of Meteorology’s seasonal outlook for July to September 2022 is indicating less than 40% chance of above median rainfall for the SWLD. Predictive skill is moderate to good (55-75% consistent). The current longer-term outlook (at time of writing) for August to October 2022 is wetter 45-70%, with poor to good skill (45-75%).
- Temperature outlooks for July to September 2022, from the Bureau indicate a 60-80% chance of above average day-time maxima, with the higher chances along the coast. Skill is 65-75%. For night-time minima for the SWLD, the Bureau is indicating 60-80% chance of exceeding above average temperatures, with the higher chances along the coast. Skill is poor at 45-65%.
- For July to October the SSF forecast is indicating above 60% probability of above median rainfall for parts of the Central West, Central Wheatbelt, Lower West, South West, Great Southern and South East Coastal forecast districts. Less than 40% probability for South Coastal forecast district, and neutral (40-60%) probability for the remainder. The most likely decile range map is indicating decile 8-9 for parts of the Central West, Central Wheatbelt, Lower West, South West, Great Southern and South East Coastal forecast districts, decile 2-3 for South Coastal forecast district and decile 4-7 elsewhere. Skill is poor to good at 50 to 70% consistent.
- June rainfall was below average to average for the SWLD. June maximum and minimum temperatures were average to above average.
- The main climate driver influencing South West Land Division climate is the positive Southern Annular mode, which suppresses the activity of cold fronts in the Southern Ocean, reducing rainfall to the SWLD. July rain will likely to be below average for SWLD. Models are indicating the development of a negative IOD in July and persisting until at least October at this stage. Past negative IOD events generally increase rainfall in the eastern grainbelt.
Three Month Outlook for the south-west of Western Australia
Statistical Seasonal Forecasting (SSF)
DPIRD’s Statistical Seasonal Forecast (SSF) system uses historical relationships between global sea surface temperature and sea level pressure with rainfall in south-west Australia to produce forecasts of rainfall for the coming months. Users can click on any station indicated on the map for location-specific forecast information from DPIRD’s Seasonal Climate Information pages.
For July to September, the SSF forecast is indicating above 60% probability of above median rainfall for parts of the Central West, Central Wheatbelt, Lower West, South West and South East Coastal forecast districts, with neutral (40-60%) probability for the remainder. The most likely decile range map is indicating decile 8-9 for parts of the Central West, Central Wheatbelt, Lower West, South West and South East Coastal forecast districts, decile 2-3 for part of the South Coastal forecast district and decile 4-7 elsewhere. Skill is poor to good at 50 to 70% consistent.
