Adelaide 28-day rainfall forecast
Chance of rainfall somewhere within district
Issued 20 Oct 2017
The hemispheric long wave pattern has remained stable in recent weeks. There are four main troughs. Currently the most significant troughs are near the longitudes of South Africa, Western Australia, eastern Australia, New Zealand, and the south Pacific. Summary: Over southern and eastern Australia the cold front events with potential to bring widespread rain are now expected about 28 October to 1 November, 4 November to 8 November, and 10 November to 14 November. Rain events originating in the tropics and moving south are possible about 25 October to 29 October, 7 November to 11 November, and 11 November to 15 November. Over Western Australia the strongest cold fronts should occur about 27 October to 31 October, 4 November to 8 November, and 11 November to 15 November.
This forecast is produced by a multi-model ensemble consisting of dynamical atmospheric models, which are forced by the latest observed atmosphere, ocean, land and ice conditions. The models are designed to simulate features of the real atmosphere, including the daily movement of long and short wave patterns in the Southern Hemisphere.
The future probability of rain in each district is estimated using output from the multi-model ensemble, combined with historical information about the difference between the model forecasts and observed rainfall.
In this deterministic framework the skill of the forecast tends to decrease with time, however the forecasts are updated daily to provide the latest estimates of rainfall probability out to 28 days.