Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) outlook for April to June 2022 is indicating mostly neutral (40-60%) probability of above median rainfall for the South West Land Division (SWLD). The longer lead SSF outlook for April to October is also indicating mostly neutral probability of above median rainfall.
- For April to June 2022, the SSF is mostly neutral (40-60%) probability of above median rainfall for the South West Land Division. Less than 40% probability for parts of Central West, South Coastal and South East Coastal forecast districts. Higher (60%) probability for parts of Central Wheatbelt, Lower West and South West forecast districts. The most probable rainfall decile map indicates decile 2-3 for parts of Central West, Great Southern, South Coastal and South East Coastal forecast districts. Decile 8-9 for Lower West, South West and area around Katanning. Decile 4-7 elsewhere. Predictive skill based on March conditions is moderate to good (60-100% consistent).
- The Bureau of Meteorology’s seasonal outlook for April to June 2022 is indicating neutral (40-60%) 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 May to July 2022 is lower chances (less than 45%) with similar skill (55-75%).
- Temperature outlooks for April to June 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 70- 80% chance of exceeding above average temperatures skill is 45-55%.
- The SSF forecast for SWLD April to October 2022 rainfall is indicating mostly neutral (40-60%) probability of above median rainfall for the South West Land Division. Less than 40% probability for parts of Central West, South Coastal and South East Coastal forecast districts. Higher probability (above 60%) for the northern part of the central west, part of the lower west, south west forecast districts and around Esperance. Most likely decile range map is indicating decile 2-3 for large part of the SWLD. Decile 8-9 for Lower West, South West and northern part of the Central West forecast district. Decile 4-7 elsewhere. Skill is poor to good at 50 to 75 % consistent.
- March rainfall was average to above average for the SWLD. A series of thunderstorms brought heavy rain to parts of the northern and eastern grainbelt. March maximum temperatures were mostly average, with minimum temperatures above average.
- The main climate driver influencing Australia rainfall is the La Niña in the Pacific, which is past its peak. La Niña increases the likelihood of tropical cyclones within the Australian region. The destructive TC Seroja hit Kalbarri on 11 April 2021, so there is still time for a tropical cyclone to develop this season. Another climate driver to look out for is the possibility of a negative Indian Ocean Dipole developing in July. This would bring increased rainfall to eastern grainbelt and cooler days to the south. Although skill is poor at this time of the year, as autumn is the ‘predictability barrier’ for forecasting.
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 Land Division 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 April to June 2022, the SSF is mostly neutral (40-60%) probability of above median rainfall for the South West Land Division. Less than 40% probability for parts of Central West, South Coastal and South East Coastal forecast districts. Higher (60%) probability for parts of Central Wheatbelt, Lower West and South West forecast districts. The most probable rainfall decile map indicates decile 2-3 for parts of Central West, Great Southern, South Coastal and South East Coastal forecast districts. Decile 8-9 for Lower West, South West and area around Katanning. Decile 4-7 elsewhere. Predictive skill based on March conditions is moderate to good (60-100% consistent).
