Forecast skill of the Indian monsoon and its onset in the ECMWF seasonal forecasting system 5 (SEAS5)

Abstract Accurate forecasting of variations in Indian monsoon precipitation and progression on seasonal time scales remains a challenge for prediction centres. We examine skill the seasonal-mean summer its onset European Centre Medium-Range Weather Forecasts (ECMWF) system 5 (SEAS5). analyse hindcasts initialised 1st May, with 51 ensemble members, 36-year period 1981–2016. evaluate against Global Precipitation Climatology Project (GPCP) observations ECMWF reanalysis (ERA5). The model has significant at dynamical features large-scale local-scale tercile category one month advance. SEAS5 shows higher calculated using indices compared to those smaller scales. Our results also highlight possible deficiencies all India rainfall.