Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) outlook for winter, June to August 2021 is indicating less than 40% chance of exceeding median rainfall for the majority of the South West Land Division (SWLD). The SSF longer outlook for June to October is similar.
- For winter, June to August 2021, the SSF is indicating less than 40% chance of exceeding median rainfall for the majority of the South West Land Division (SWLD). The most probable rainfall decile map indicates decile 2-3 for the SWLD. Predictive skill based on May conditions is mostly poor to good (50-75% consistent).
- The longer lead SSF forecast for June to October 2021 rainfall is indicating less than 40% chance of exceeding median rainfall for the majority of the SWLD. Most likely decile range maps is indicating decile 2-3 for the SWLD. Skill is poor to good at 50 to 100 % consistent.
- The Bureau of Meteorology’s seasonal outlook for winter, June to August indicated 30-50% chance of exceeding median rainfall for the SWLD. Predictive skill is poor to moderate (50-65% consistent). The current outlook for July to September is similar, 35-65% chance of exceeding median rainfall with higher chances along the southern coast. Skill is poor to moderate (45-65%).
- Temperature outlooks for winter June to August 2021, from the Bureau indicate a 50-80% chance of above average day-time maxima (skill 75-100%) and 55-80% chance of exceeding above average night-time minima for most of the SWLD (skill 45-65%).
- May rainfall was very much above average for SWLD due to a series of cold fronts. Autumn rainfall, March to May was decile 8-10 for most of the SWLD, wettest since 2016. May maximum temperatures were generally average. Minimum temperatures were above average to very much above average.
- The Southern Annular Mode is the main climate driver for the SWLD in winter, when it is in a negative phase it brings more rain, it is forecast to be neutral until the end of June.
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 winter, June to August 2021, the SSF is indicating less than 40% chance of exceeding median rainfall for the majority of the South West Land Division (SWLD). The most probable rainfall decile map indicates decile 2-3 for the SWLD. Predictive skill based on May conditions is mostly poor to good (50-75% consistent).
