Analysis on the Causes of a Regional Rainstorm in the South of Shanxi Province in August,2012

Based on the conventional observational data,automatic station and precinct meteorological observational data,the regional rainstorm occurred in the south of Shanxi Province on August 16～18,2012 is analyzed.The results showed that the rainstorm occurred while short wave trough went eastward and the subtropical high backed to the south.The shear lines on the 700 hPa and 850 hPa,with the surface mesoscale convergence line were the main influencing systems.The strong ascending motion and the thermal instability supplied the favorable dynamic condition and thermal condition for the regional rainstorm.The surface mesoscale convergence line and the heavy rain area had a good corresponding relationship.