Seasonal Climate Outlook

Summary

The Department of Primary Industries and Regional Development’s (DPIRD) Statistical Seasonal Forecast (SSF) system is indicating generally a neutral, 40-60%, chance of exceeding median rainfall for summer, December 2018 to February 2019 for the South West Land Division (SWLD).

  • The SSF is indicating for summer, December 2018 to February 2019, neutral (40-60%) chances of exceeding median rainfall for the majority of the grainbelt. Greater chances, 60-70% for the far northern grainbelt. The most probable decile range is decile 4-7 for most of the grainbelt. With decile 8-10 rainfall likley for parts of the northern and southern grainbelt. Predictive skill based on November conditions is mostly poor to good (50- 70% consistent).
  • The Bureau of Meteorology’s current seasonal outlook is indicating roughly equal chances (40-50%) of exceeding or below median rainfall for summer, December 2018 to February 2019 for mostly of the SWLD, with small areas to the north showing a tendency towards below median rainfall (35-40%). Predictive skill is moderate to good (55-75% consistent).
  • Temperature outlooks for summer, December 2018 to February 2019, from the Bureau indicate 60-80% chance of above average day-time maxima for the SWLD away from the coasts. Skill is moderate to good at 55-75% consistent. Minimum temperature outlooks indicate 60-75% chance of above average night-time minima for most of the SWLD except the northwestern areas with 50-60% chancewith skill mostly moderate to good at 55-75% consistent.
  • November rainfall was below average in some parts of the northern and central grainbelt, above average in the eastern grainbelt and average elsewhere. Reports of heavy rainfall and hail in mid-November and early December, interfered with harvesting in some central and eastern areas. November maximum and minimum temperatures were below average to 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 web page.

The SSF is indicating for summer, December 2018 to February 2019, neutral (40-60%) chances of exceeding median rainfall for the majority of the grainbelt. Greater chances, 60-70% for the far northern grainbelt. The most probable decile range is decile 4-7 for most of the grainbelt. With decile 8-10 rainfall likley for parts of the northern and southern grainbelt. Predictive skill based on November conditions is mostly poor to good (50- 70% consistent).

SSF forecast of the probability of exceeding median rainfall for December 2018 to February 2019 using data up to and including November. Indicating generally neutral chance of the Southwest Land Division receiving above median rainfall for summer.
SSF forecast of the probability of exceeding median rainfall for December 2018 to February 2019 using data up to and including November.

Percent Consistent skill of the SSF at forecasting December to February rainfall using data up to and including November. Skill is 50 to 70 percent consistent.
Percent Consistent skill of the SSF at forecasting December to February rainfall using data up to and including November.