Seasonal Climate Outlook

Summary

The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) system is indicating mixed chances of exceeding median rainfall for October to December 2017 for the south-west land division which includes the wheatbelt.

  • The SSF is indicating less than 40% chance of exceeding median rainfall for the south-west corner and western parts of the northern wheatbelt. The eastern and southern wheatbelt have higher chances (greater than 60%) and neutral (40-60%) elsewhere. The most probable decile range map indicates decile 2-3 rainfall is most likely for northern wheatbelt and south-west corner, decile 8-10 for eastern and southern wheatbelt and decile 4-7 for elsewhere. Predictive skill based on September conditions is poor to good (50-70% consistent).
  • The Bureau of Meteorology’s current seasonal outlook indicates that much of the south west land division (SWLD) has a 40-45% chance of exceeding median rainfall for October to December. For Jerramungup, Ravensthorpe and Esperance this chance is higher at 45-50%. Predictive skill is poor to moderate (45-65% consistent).
  • Temperature outlooks for October to December from the Bureau indicate a 45-65% chance of above normal day-time maxima for the SWLD. Skill is moderate to good at 55-75% consistent. Minimum temperature outlooks indicate 35-65% chance of above normal night-time minima for the SWLD, with poor to moderate skill at 45-65% consistent.
  • September rainfall in the SWLD was average to above average with a cut-off low on the 24-26 September bringing widespread rain to the SWLD. September maximum temperatures were near average and minimum temperatures were above average.

Three month outlook for the south-west of Western Australia

Statistical Seasonal Forecasting (SSF)

The department's 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 web page.

The SSF forecast for October to December 2017 is indicating less than 40% chance of exceeding median rainfall for the south-west corner and western parts of the northern wheatbelt. The eastern and southern wheatbelt have higher chances (greater than 60%) and neutral (40-60%) elsewhere. Predictive skill based on September conditions is poor to good (50-70% consistent). The most probable decile range map indicates decile 2-3 rainfall is most likely for the northern wheatbelt and south-west corner, decile 8-10 for the eastern and southern wheatbelt and decile 4-7 for elsewhere.

SSF forecast of probability of exceeding median rainfall for October-December 2017. Indicating mixed chance of exceeding median rainfall with low chance less than 40% for south-west corner and western parts of the northern wheatbelt. Eastern and southern

SSF forecast of probability of exceeding median rainfall for October-December 2017

Percent Consistent skill of the SSF at forecasting October to December rainfall using data up to and including September.

Percent consistent skill of the SSF at forecasting October to December rainfall using data up to and including September