Performance of the operational <scp>ECMWF</scp> ensemble in predicting heavy rain associated with the Emilia‐Romagna flood in May 2023

Abstract A devastating flood occurred in May 2023 in the Emilia‐Romagna region in northern Italy following a 2‐day period with widespread accumulated precipitation exceeding 150mm. The event was associated with a quasi‐stationary upper‐level cutoff cyclone. This study investigates the performance of the operational ECMWF ensemble prediction system in capturing the cutoff formation and the occurrence of intense precipitation. The key results are that forecasts with a 1‐day lead time were highly accurate and that a predictability jump occurred for lead times larger than 4 days, when the ensemble failed in representing the formation of the cutoff.