Subseasonal prediction of Australian summer monsoon anomalies

Subseasonal prediction of Australian summer monsoon anomalies is assessed using 30years of retrospective forecasts from version 2 of the Predictive Ocean Atmosphere Model for Australia. Active and break monsoon rainfall episodes are associated with large-scale cyclonic westerly and anticyclonic easterly winds, respectively, for which the Madden-Julian oscillation (MJO) makes a dominant contribution and thus is a source of predictability. Although the forecast model can predict the local large-scale zonal wind anomalies for lead times beyond 4weeks, predictive skill of the monsoon rainfall anomalies is limited to about 2weeks. We show that improving the prediction of the MJO and its local expression in the summer monsoon leads to improved monsoon rainfall predictions at multiweek timescales.