Summary
Rainfall outlook for the South West Land Division (SWLD) for spring, September to November, and for the remainder of the year is for below median rainfall, based on a survey of 20 national and international models. Warmer temperatures than normal are expected for spring.
Things to consider:
- The Bureau of Meteorology rainfall outlook is indicating a higher than normal chance of reduced rainfall for spring, although the skill of the forecast is poor at this time of year.
- The Bureau of Meteorology temperature outlook for spring is indicating an 80% chance of exceeding median maximum and minimum temperatures. Skill of these outlooks are 65-100%, however frosts still do occur in September and are more likely this month, given the reduction in cloud cover.
- The Bureau's El Niño Alert continues, with El Niño development likely during spring, as well as the development of a positive Indian Ocean dipole. These two climate drivers together will reduce rainfall for the SWLD until November.
- The Bureau is forecasting a series of high pressure systems over Western Australia this spring. This will mean fewer cold fronts, less westerly winds and an increase in warm easterly winds and drier and warmer conditions for spring.
- The next weak cold front is forecast for 3 September with the European Centre for Medium-Range Weather Forecasts (ECMWF) indicating between 5-15mm for the South West Land Division.
Rainfall outlook for the South West Land Division
Summary of 20 national and international models show that all models indicate below normal chances of exceeding median rainfall for the SWLD for September to October 2023, and further ahead to the end of the year. Out of a survey of 6 models, half indicate below median rainfall for December 2023 to February 2024. Remember, however, the further out the model forecasts, the least skill it has.
Model summary of rainfall outlook for the South West Land Division up to December 2023 to February 2024