Summary
The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) system is indicating less than 40% chance of exceeding median rainfall for summer, December 2017 to February 2018 for the majority of the wheatbelt.
- The SSF is indicating 60-70% chance of exceeding median rainfall for the far northern agriculture region and south-west corner. This chance has increased to 70-80% for the Perth region. This region typically has low rainfall over summer.There is less than 40% chance for northern, central and eastern agricultural regions, with neutral (40-60%) chances elsewhere. The most probable decile range map indicates decile 2-3 rainfall is most likely for eastern and central wheatbelt, with decile 8-10 rainfall for the far northern wheatbelt and south-west corner and decile 4-7 elsewhere. Predictive skill based on November conditions is poor (50-60% consistent) across most of the region.
- The Bureau of Meteorology’s current seasonal outlook indicates generally a neutral outlook, with 45-60% chance of exceeding median rainfall for summer for the South West Land Division (SWLD). Predictive skill is poor to good (50-75% consistent). For the individual month of December the chance is lower at 35-45%.
- Temperature outlooks for summer, December 2017 to February 2018 from the Bureau indicate a 45-65% chance of above normal day-time maxima for the SWLD. Skill is moderate to good at 50-75% consistent. Minimum temperature outlooks indicate a 55-65% chance of above normal night-time minima for the SWLD, with moderate to good skill at 50-75% consistent.
- November rainfall in the SWLD was below average to near average. November maximum and minimum temperatures were very much above average.
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 the Seasonal Climate Information page.
For summer, December 2017 to February 2018, the SSF is indicating 60-70% chance of exceeding median rainfall for the far northern agricultural region and south-west corner. This chance has increased to 70-80% for the Perth region. This region typically has low rainfall over summer, so the outlook is not necessarily indicating heavy rainfall. There is less than 40% chance for northern, central and eastern agricultural regions, with neutral (40-60%) chances elsewhere. The most probable decile range map indicates decile 2-3 rainfall is most likely for the eastern and central wheatbelt, with decile 8-10 rainfall for the far northern wheatbelt and south-west corner and decile 4-7 elsewhere. Predictive skill based on November conditions is poor to good (50-70% consistent). Note that most of the region has low skill at this time of year.
