Environmental conditions and mesoscale convective cloud during a severe convective rainstorm process

The large scale circulation,influence system,environmental conditions,vertical wind shear and mesoscale characteristics during a severe convective storm process occurred in the east of Ningxia at night were analyzed by using the conventional observation data,NCEP/NCAR reanalyzed data,hourly FY-2E infrared cloud images,automatic weather station data and local mesoscale numerical weather prediction model WRF.The results showed the rainstorm event occurred under beneficial large scale circulation background and environmental conditions.During the rainstorm process,west pacific subtropical high moved toward north-west,low altitude jet developed,the combined action of plateau trough,low vortex with shear,ground cold front and ground convergence line excited mesoscale weather systems and then caused convective rainstorm in the east of Ningxia;Along with the approaching of rainstorm,low altitude jet and vertical wind shear developed,wet layer thickened,air in the middle and low altitude level was tending to saturated,east wind persisted at surface layer,inversion layer maintained over low level wet layer,convective unstable energy released rapidly;Severe convective rainstorm occurred at the end of developing stage and beginning of mature stage of mesoscale convective cloud,at the right-front of surface cyclonic circulation,the north side of ground convergence line,the front of mesoscale convective cloud and back of cold cloud center;At the weather stations where rainstorm occurred,the variation of TBB and precipitation was consistent,the peak value of precipitation was corresponding with the peak value of TBB.