Diagnostic Analysis of One Widespread Thunderstorm Coexisting with Snowstorm in North China in March 2013
A relatively rare process of widespread thunderstorm coexisting with snowstorm was analyzed by adopting conventional meteorological data, CINRAD radar data, and NCEP analysis data. The results are as follows. The widespread thunderstorm was an elevated thunderstorm over the lowlevel cold air mass. Although lowlevel convergence of moisture flux was weak over the thunderstorm area, the deep warm advection formed over Hebei, and decreased with height in the middleupper troposphere, leading to conditional instability. The 850 hPa shear line and convergence zone in the southwest airflow caused convective instability energy to release. Strong moisture flux convergence was suddenly thickened around the middle troposphere in the north of Hebei, and the strong convergence of southwest airflow and west airflow in the front of the 700 hPa trough formed, which led to heavy snowfall in central Hebei. In addition, at the middlelower level, positive differential vorticity advection was more distinct than divergence in expressing dynamic action.