Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) outlook for October to December 2022, is indicating mostly neutral (40-60%) probability of above median rainfall for the majority of the South West Land Division (SWLD).
- For October to December 2022, the SSF forecast is indicating mostly neutral (40-60%) probability of above median rainfall for the majority of the South West Land Division. Greater than 60% probability for part of the Central West and Central Wheatbelt forecast districts. With less than 40% probability for parts of the South East Coastal forecast district. The most likely decile range map is indicating decile 8-9 for parts of the Central West, Central Wheatbelt, Great Southern, South West and South Coastal forecast districts. Decile 2-3 for parts of the Central Wheatbelt, Great Southern, South West and South East Coastal forecast districts, and decile 4-7 elsewhere. Skill is poor to moderate at 50 to 70 % consistent.
- The Bureau of Meteorology’s seasonal outlook for October to December 2022 is indicating 25-65% chance of exceeding median rainfall for the SWLD. The higher chances are for parts of the Great Southern, South Coastal and South East Coastal forecast districts. Predictive skill is poor to moderate (45-65% consistent). The current longer-term outlook (at time of writing) for November 2022 to January 2023 is neutral (40-60%) chance of exceeding median rainfall with mostly moderate skill (50-75%).
- Temperature outlooks for October to December 2022, from the Bureau indicate a 20-80% chance of above average day-time maxima, with the lower chances for Great Southern, South Coastal and South East Coastal forecast districts. Skill is good at 75-100%. For night-time minima for the SWLD, the Bureau is indicating 40- 80% chance of exceeding above average temperatures, with the higher chances along the coast. Skill is good at 75-100%.
- September rainfall was above average for the Central West and Central Wheatbelt forecast districts, below average for South West and South Coastal forecast districts and average elsewhere. September maximum temperatures were average to above average, with below average in land, and minimum temperatures were average to above average. Minimal reports of frost damage.
- The main climate driver influencing South West Land Division climate is the high Mean Sea Level Pressure which is predicted to remain high throughout spring. The Indian Ocean Dipole (IOD) is currently negative and likely to remain through to November. Past negative IOD events generally increase rainfall in the eastern grainbelt. The La Niña in the Pacific, and the positive Southern Annular Mode have little influence on SWLD summer rainfall.
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 October to December 2022, the SSF forecast is indicating mostly neutral (40-60%) probability of above median rainfall for the majority of the South West Land Division. Greater than 60% probability for part of the Central West and Central Wheatbelt forecast districts. With less than 40% probability for parts of the South East Coastal forecast district. The most likely decile range map is indicating decile 8-9 for parts of the Central West, Central Wheatbelt, Great Southern, South West and South Coastal forecast districts. Decile 2-3 for parts of the Central Wheatbelt, Great Southern, South West and South East Coastal forecast districts, and decile 4-7 elsewhere. Skill is poor to moderate at 50 to 70 % consistent.
