Seasonal Climate Outlook

Summary

The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) system is indicating below median rainfall for the majority of the South-West Land Division (which includes the wheatbelt) for spring, September to November 2017.

  • The SSF is indicating less than a 40% chance of exceeding median rainfall for spring, September to November, for the majority of the wheatbelt. For western areas of the central agricultural area, chances are higher at 40-60%. For eastern areas of the metropolitan region, chances are higher still at 60-70%. The most probable decile range map indicates decile 2-3 rainfall is most likely for the majority of the wheatbelt. Predictive skill based on August conditions is poor to good (50-75% consistent).
  • The Bureau of Meteorology’s current seasonal outlook indicates the South-West Land Division (SWLD) has a 30-50% chance of exceeding median rainfall for spring, September to November. Predictive skill is poor to moderate (45-65% consistent).
  • Temperature outlooks for September to November from the Bureau indicate a 30-60% chance of above normal day-time maxima for the SWLD. Skill is poor to good at 45-75% consistent. Minimum temperature outlooks also indicate 30-60% chance of above normal night-time minima for the SWLD, with poor to moderate skill at 45-65% consistent. Frost risk remains in areas with clear skies and dry soils.
  • August rainfall in the SWLD was average to above average, with parts of the Great Southern and Esperance shire below average. 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)

DPIRD’s Statistical Seasonal Forecast 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 spring, September to November 2017 is indicating less than a 40% chance of exceeding median rainfall for the majority of the wheatbelt. For western areas of the central agricultural area, chances are higher at 40-60%. For eastern areas of the metropolitan region chances are higher still at 60-70%. Predictive skill based on August conditions is poor to good (50-75% consistent). The most probable decile range map indicates decile 2-3 rainfall is most likely for the majority of the wheatbelt.

SSF forecast of probability of exceeding median rainfall for spring, September to November 2017 indicating 0-40% chance of exceeding median rainfall for the majority of the wheatbelt.
SSF forecast of probability of exceeding median rainfall for spring, September to November 2017

Percent Consistent skill of the SSF at forecasting September to November rainfall using data up to and including August. Skill is between 50 to 75 percent consistent at this time of the year.
Percent Consistent skill of the SSF at forecasting September to November rainfall using data up to and including August