Analysis of the structure and environment of a squall line in Huaihe river basin in 2014

A squall line moved through Huaihe river basin on June 1th. 2014. Using Doppler radar data, the Local Analysis and Prediction System (LAPS) and surface observation data etc., the structure and the environment characteristics of the squall line were analyzed. A cold front provided the primary lifting responsible for the formation of the squall line, which located south of the tough in the middle level of troposphere. Initially, the precipitation took a"人"shape, being stronger in west part. A squall line occurred in the west part. The squall line brought mainly heavy rain. When the squall line was at the strongest stage, the classical bow echo appeared. There was a pair of anticyclone and cyclone on the two ends of the squall line, respectively. At the same time, a cold-dry air sank from the high level of troposphere and rolled into the rear of the squall line, and then the rear inflow became faster. Near surface, there was 16.6 m·s^-1 gale. After the outflow cut off the inflow in low level, the downdraft was dominant in the rain area, and the squall line quickly declined. The squall line brought a weak cold pool. The lifetime of the squall line was about 5 h.