Do subseasonal forecasts take advantage of <scp>Madden–Julian oscillation</scp> windows of opportunity?

This study proposes an objective methodology to highlight windows of opportunity in a numerical subseasonal forecasting system. The is based on contingency table and applied the prediction heavy tropical precipitation by European Centre for Medium-range Weather Forecasts (ECMWF) subseasonal-to-seasonal (S2S) reforecasts November-to-April season, relation with Madden–Julian oscillation (MJO). As slowly propagating signal enhanced convection, MJO may indicate favorable conditions few weeks ahead some areas. combined knowledge these climatological impacts current phase at initialization defines observation-based “climatological opportunity.” We then investigate whether ECMWF S2S forecasts are indeed more performant when there increased likelihood rainfall, that is, model converts opportunity” into “model Our results show that, Week 2, this only verified limited number areas, mostly located western Pacific Africa. Meanwhile, failures seize opportunities lie misplaced impacts, loss, or too many false alarms.