Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) outlook for May to July 2022 and May to October 2022 is indicating below 40% probability of above median rainfall for the South Coastal and South East Coastal forecast districts, with higher probabilities for the remainder of the South West Land Division.
- For May to July 2022, the SSF is indicating below 40% probability for the South Coastal and South East Coastal forecast districts, above 60% for parts of the Central West and Central Wheatbelt, South West and western part of the Great Southern forecast districts. With neutral (40-60%) probability elsewhere. The most probable rainfall decile map indicates decile 2-3 for South Coastal and South East Coastal forecast districts. Decile 8-9 for parts of the Central West, Central Wheatbelt, South West and western part of the Great Southern forecast district. Decile 4-7 elsewhere. Predictive skill based on April conditions is moderate to good (60-100% consistent).
- The Bureau of Meteorology’s seasonal outlook for May to July 2022 is indicating neutral (40-55%) chance of above median rainfall for the SWLD. Predictive skill is moderate to good (55-100% consistent). The current longer-term outlook (at time of writing) for winter June to August 2022 is also mostly neutral, with lower chances (35-45%) for the northern grainbelt, with moderate to good skill (55-75%).
- Temperature outlooks for May to July 2022, from the Bureau indicate a 45-80% chance of above average day-time maxima, with the higher chances along the coast. Skill is 75-100%. For night-time minima for the SWLD, the Bureau is indicating 55- 80% chance of exceeding above average temperatures, with the higher chances along the coast. Skill is poor mostly at 45-55%.
- The SSF forecast for SWLD May to October 2022 rainfall is indicating less than 40% probability of above median rainfall in South Coastal, South East Coastal and coastal parts of the Lower West and southern coastal parts of the Central West forecast districts. Above 60% for parts of the Central West, Central Wheatbelt and South West and western part of the Great Southern forecast districts, with neutral probability elsewhere. The most likely decile range map is indicating decile 2-3 for South Coastal and South East Coastal forecast districts. Decile 8-9 for South West, western part of the Great Southern, parts of the Central West and Central Wheatbelt forecast districts. Decile 4-7 elsewhere. Skill is poor to good at 50 to 75 % consistent.
- April rainfall was average to above average for the SWLD. Munglinup in the South East Coast forecast district, received 230 mm of rain. April maximum temperatures were mostly below average, with minimum temperatures average.
- The main climate drivers influencing South West Land Division climate is the positive Southern Annular mode, which may suppress the activity of cold fronts in the Southern Ocean. Models indicate a negative Indian Ocean Dipole developing in May and persisting until at least September. This would bring increased rainfall to the eastern grainbelt and cooler days in the south, however there is low confidence in the skill of the models at this time.
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 May to July 2022, the SSF is indicating below 40% probability for the South Coastal and South East Coastal forecast districts, above 60% for parts of the Central West and Central Wheatbelt, South West and western part of the Great Southern forecast districts. With neutral (40-60%) probability elsewhere. The most probable rainfall decile map indicates decile 2-3 for South Coastal and South East Coastal forecast districts. Decile 8-9 for parts of the Central West, Central Wheatbelt, South West and western part of the Great Southern forecast district. Decile 4-7 elsewhere. Predictive skill based on April conditions is moderate to good (60-100% consistent).
