In recent years, extreme rainfall events such as the "21·7" Henan and "23·7" Beijing-Tianjin-Hebei storms have frequently impacted North China and the Huanghuai region (North China-Huanghuai region). These events exposed significant gaps in our understanding of their physical mechanisms. This article summarizes recent researches on spatial-temporal features, synoptic patterns, mesoscale convective systems (MCSs), and microphysical structures of extreme rainfall. By combining multi-source observations and model simulations, the study highlights the multiscale processes—from large-scale circulation to microphysics—that jointly shape rainfall intensity. A multiscale pattern recognition method is proposed to improve the identification of extreme events. Two distinct MCS types—warm-type and deep-convective-type—are characterized, especially in terms of raindrop spectra and hydrometeor composition. A multiscale conceptual model tailored to North China is presented, offering insights to improve forecasting and model representation of extreme rainfall processes.

A Mesoscale Convective System (MCS) is a cloud system composed of multiple convective systems. Its horizontal precipitation scale falls between that of individual thunderstorms and mid-latitude cyclones, with a temporal scale usually lasting several hours or more. MCSs are often associated with severe high-impact weather events. Influenced by systems like the Qingzang plateau and the East Asian monsoon, MCSs in China exhibit many unique characteristics, significantly affecting regional hydrological cycle, heavy rainfall events, and flooding disasters in China. Research on MCSs holds considerable scientific significance and practical value, playing a crucial role in improving weather forecasting capabilities. This paper reviews the research achievements and progresses made by Chinese scholars in the field of MCSs' variability and climate responses. With the advent of MCS observational studies in China since the 1960s, research has advanced from case-specific and short-term analyses to comprehensive examinations of multi-regional and long-term characteristics and mechanisms of MCS. Chinese meteorologists have extensively analyzed the spatial and temporal variabilities of MCS, linking them to background conditions to obtain significant insights into MCSs' long-term variability and mechanisms. This paper introduces relative studies on interannual and decadal variabilities of MCS across different regions in China, and the regulatory effect of climate on MCS on these timescales. This paper also reviews researches about the responses of MCS to global warming, including the influences of climate change on MCS frequency and intensity and the effects of human activities, i.e., aerosol emissions and urbanization. This paper concludes with a discussion of potential future research on MCS.