Characteristics of Elevated Thunderstorms on the Cold Side of Fronts in China during the Period 2017–21

Abstract Elevated thunderstorms are a type of convection that occurs above a stable layer. Elevated thunderstorms occurring on the cold side of fronts (ETCFs) in China remain poorly understood due to limited observational data. ERA5 reanalysis data, Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) precipitation data, and cloud-to-ground (CG) lightning data spanning 2017–21 are used to identify and characterize ETCFs to build a climatology. In general, ETCFs are mainly located in Hunan and Guizhou Provinces. The annual cycle exhibits a peak in spring, and the diurnal cycle exhibits a peak at night. In winter, almost all CG lightning in Hunan and Guizhou is in ETCFs. ETCFs initiate primarily on the east side of mountains and move from west to east. The main weather pattern of ETCFs in Southwest China is as follows: the cold air near the surface is blocked and forms a “cold-air damming” due to the blocking of mountains, and there is a low-level jet above the front and a cyclonic circulation in the middle and lower troposphere. ETCFs in the Northeast China cold vortex (NCCV), predominantly occurring during summer, are typically located to the north of warm fronts. Under the influence of NCCV and the cold air near the surface, warm and moist air climbs along the fronts, triggering the development of ETCFs. These results offer valuable insights into understanding the climatology of ETCFs in China better. Significance Statement Elevated thunderstorms, a form of deep moist convection, have not been sufficiently studied despite their potential to produce severe weather such as hail, strong winds, and tornadoes. This paper presents the first comprehensive analysis of elevated thunderstorms on the cold side of fronts (ETCFs) in China. The characteristics of ETCFs are revealed through the analysis of spatial and temporal distribution, movement, and weather patterns. Hunan, Guizhou, and their surrounding areas are the frequent areas of ETCFs, and the ETCFs are greatly affected by terrain. This study establishes a foundation for future research on ETCF mechanisms and aims to enhance the accuracy of ETCF forecasting.