Comparative analysis of two squall lines happened in the Northeast of Yunnan province

Based on conventional data,automatic station data,satellite cloud images and Doppler radar data,two squall lines happened in the northeast of Yunnan Province were analyzed.The result showed that boundary layer convergence line triggered strong convective storm,the lifting of the mountain accelerated the development of strong convection.The 2007.6.14 squall line happened in the warm region before cold front,the major weather phenomena were hail and strong wind.The 2009.6.19 squall line happened before cold front,the major weather phenomena were hail and strong wind first,then heavy rainfall.There were both bowlike echo and convergence region at low level in the front of the squall line in radar echo data,but the 2007.6.14 squall line was bowlike echo cells which caused hail and strong wind,the 2009.6.19 squall line was bowlike echo complex,and there was also mesocyclone in it.The supercell in the right front of the squall line caused hail and strong wind directly.The long time maintenance of the convergence region at low level caused heavy rainfall.