Abstract:Based on the NCEP reanalysis, radar, satellite data, and lightning data, the process of a severe thunderstorm occurred in Hohhot on 27 July 2019 was analyzed. Results show that the thunderstorm process is mainly affected by the eastward movement of the low-pressure center of Lake Baikal and the upper-level trough of the Mongolian Plateau. Before the thunderstorm, the unstable parameters such as K index and CAPE are above the thresholds, leading to the unstable atmospheric stratification as the upper dry and low moist vertical profile. Furthermore, the vertical structure of low-level convergence and high-level divergence in conjunction with the strong updrafts, which provides the favorable conditions for the thunderstorm. Negative Cloud-to-Ground (CG) lightning dominates the whole storm process, but the distribution of CG lightning varies at different stages. The negative CG lightning counts are significantly higher than the positive CG lightning counts at the developing and mature stages while the number of positive CG lightning increases dramatically, even more than negative CG lightning at the dissipating stage. Most CG lightning is distributed in the region of strong echoes, but the highest lightning frequencies do not necessarily correspond to the center of the strong echoes. The CG lightning is mainly located in regions where the cloud top temperature is colder than 240 K, in which the cloud top phase is the ice phase and mixed phase.