Contrasts in the Evolution and Microphysical Features of Two Convective Systems during a Heavy Rainfall Event along the Coast of South China

On 1 June 2021, a heavy rainstorm hit the coast of South China (148.6 mm in h, 361 over 12 h). The storm process was successively affected by two convective systems (CSs). initial convection CSs occurred at similar location; however, they subsequently showed different evolution characteristics. Based on multi-source data, including dual-polarimetric radars, wind profiling sounding, and automatic weather stations, we explored differences key characteristics these CSs. It found that initially triggered location for both CSs, closely related to mesoscale boundary hilly terrain. After formation, CS1 moved eastward regions with lower surface temperature weaker lower-level convergence but humidity, which means environmental conditions sustaining CS became less favorable. As result, dissipated rapidly only lasted about 90 min, resulting 5% total precipitation overall storm. In contrast, during lifespan CS2, southerly Sea stronger. This caused an intense zone along coastal region Guangdong Province, provided favorable dynamic maintaining CS2. Favored strong abundant moisture, new cells (CCs) were generated continuously merged acting as another condition its sustainment. Overall, CS2 8 accounted 95% rainfall. CS1, CCs notable evaporation below 4 km, manifested large raindrops. However, had higher concentration small raindrops ice liquid water content. Since close region, warm local environment promoted convection, leading precipitation. addition, riming melting processes active, high efficiency short period time.