Abstract Mesoscale convective systems (MCSs) are crucial for the hydrological cycle and frequently produce severe hazards over the central United States and eastern China. Understanding their future changes is therefore essential. This study investigates projected changes in summer MCSs using the global cloud‐system‐resolving model, the Nonhydrostatic ICosahedral Atmospheric Model (NICAM), by comparing MCSs tracked in the historical (1951−1960) and future (2041−2050, SSP5‐8.5) periods. The results show that the fractional contribution of MCSs to summer precipitation remains nearly unchanged over the central United States and eastern China. The total number of MCS initiations exhibited little overall change in both regions. However, the frequency of MCSs with weak mean rain rates decreases, whereas that of MCSs with heavy mean rain rates increases substantially. In particular, the number of MCSs exceeding the MCS historical 90th percentile mean rain rate rises by approximately 35% per degree of mean warming in both regions. MCS mean, heavy, and maximum rain rates intensify robustly by ∼5.7%, 3.5%, and 5.2% per degree of warming, respectively, whereas changes in MCS track duration and total rain area are small and statistically insignificant. Light rain areas contract markedly, whereas extreme heavy rain areas (≥30 mm/hr) expand by approximately 11.5% per degree of warming, resulting in insignificant changes in the MCS rain area.
Na et al. (2026) studied this question.