Seasonal Climate Outlook

SSF forecast for April to October

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. Skill is poor to good at 50 to 75 % consistent.

SSF forecast of the probability of exceeding median rainfall for April to October 2022 using data up to and including March.

Percent consistent skill of the SSF at April to October rainfall using data up to and including March.

Recent climate

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.  Rainfall since 1 January has been restricted to parts of the north and eastern grainbelt.

1 January to 4 April 2022 rainfall map for the South West Land Division.

In March the atmospheric pressure was normal over the SWLD.

In March, sea surface temperatures were warmer than average around tropical Australia. The April to June, sea surface temperature outlook by the Bureau of Meteorology indicates SSTs are likely to remain warmer than normal around Western Australia

The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere. SAM is currently neutral and expected to remain neutral over the coming weeks. SAM has little influence on SWLD rainfall during autumn. For more information see the Bureau of Meteorology’s Climate Driver Update.

The Indian Ocean Dipole (IOD) is neutral. It typically has little influence on global climate from December to April due to the influence of the monsoon. Models are indicating the development of a negative IOD event by July. However, model outlooks issued at this time of the year have low skill beyond autumn. Past negative IOD events generally increase rainfall in the eastern grainbelt and bring cooler days to the south.

The 2021–22 La Niña has weakened in the tropical Pacific and is forecast to return to neutral ENSO in late autumn.

The table below gives a summary of past month and three-month South West Land Division (SWLD) climate conditions, and can indicate what is likely to occur in the near future if climate conditions follow the current pattern.