Analysis of the Environmental Conditions for Forming Mesoscale Convective Complexes in Southern North China

According to the diagnostic analysis of MCC on July 30, 1996, the cause for MCC occurring concentrately in southern North China in midsummer was discussed. It is shown that MCC in southern North China was formed in the northwestern margin of the zonality subtropical high controlling over the Huanghe-Huaihe River basin. It was the main mechanism in forming MCC that the southern low-level warm-wet air current was forced to raise over the stationary front which caused the regenerating and combining of mesoscale convective cloud cluster continually. The geographical environment in southern North China, nearby the east of Taihang mountains and by the west of the Yellow Sea and Bohai Sea, was favourable to form the high temperature zone in these areas and the preventing action of Central Shandong Mountains was benefit to form and intensify the surface stationary front. These important local factors caused MCC emerging concentrately in southern North China