Diagnostic Analysis on a Hail Storm Occurred in Zhumadian Area

According to the weather background of the hail storm,by using conventional observational data,four elements stations and Doppler radar detection data,the unstable atmospheric layer,the moisture condition and the upward motion character etc.that caused the hail storm weather on June 18,2010 in Zhumadian were discussed,and combined with the Doppler radar detection data,hail storm cloud echo characters were analyzed.It was found that the high-altitude situation is a cold-vortex,hail storm fall mainly along the surface convergence line.The K index,SI index,CAPE value,and the wind changes with height all showed clearly that the atmospheric layer is instable.0 ℃-layer-height and-20 ℃-layer-height are also conducive to the production of hail storm.Strong upward motion and deep vertical humidity values also provide favorable environmental condition.The hail storm echo area is small,but strong,accompanied by V-notch and strong convergence zone,and there is the weak echo region caused by the rising air below the strong echo.