Mechanism Analysis of a Severe Hailstorm Process in Guangxi

Based onthe NCEP reanalyzed data,MM5 numerical simulation data and the Doppler radarproducts,a severehailstormprocess occurred in north of Guangxi Province of China on April 9~10,2006 was analyzed.The results indicatethat the dry and warm lids existed previously to the severe convection process is favorable to storing of the convective available potential energy(CAPE).The increase of verticalwind shear promoted the exchanges of the upper and lower levels to unveilthe dry and warm lids,to triggerthe convection.The downward transportion of the potential vorticityof upper level cause the lower level vorticitychanges,and lead to the convergenceof lower level and divergenceof upper level,it keeps and strengthens the strong convection.The severe convection storm center is located above 500 hPa,there is a weak echo on the lower level.Storm center ascended incline and whirl clockwisefrom lower level to upper level.