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Abstract

A record-breaking precipitation event caused 398 deaths and 20.06 billion RMB economic losses in Henan Province of China in July 2021. A maximum 24-h (1-h) precipitation of 624 mm (201.9mm) was observed at the Zhengzhou weather station. However, all global operational forecast models failed to predict the intensity and location of maximum precipitation for the event. This high social impact event has drawn much attention from the research community. This study provides a high-level review of the event and its research from the perspectives of observations, analysis, dynamics, predictability, and the connection with climate warming and urbanization.Global reanalysis revealed obvious abnormality in large-scale circulation patterns that resulted in abundant moisture supplies in the region of interest. Recent studies of this event also revealed, via high-resolution model simulation and data assimilation, that three mesoscale systems (a mesoscale low pressure system, a barrier jet and downslope gravity current) contributed to the local intensification of the rainstorm. Further, observational analysis suggested that an abrupt increase of graupel through microphysical processes contributed to the record-breaking precipitation. Although these findings aided in our understanding of the extreme rainfall event, preliminary analysis indicated that the practical predictability of the extreme rainfall for this event was rather low. The contrary influences of climate warming and urbanization on precipitation extremes as revealed by two studies could add further challenges to the predictability. We concluded by emphasizing that data sharing and collaboration between meteorological and hydrological researchers would be crucial in the future research on high-impact weather events.