Application of Instability Energy Parameters to a Severe Convective Storm Forecast

The atmospheric unstable energy accumulation and release play a key role in the formation of severe convective weather.A mesoscale severe convective storm with tornado and hails at 1730 BST July 12,2004 in Nantong,Jiangsu Province is analyzed in this paper by using the conventional observational data and the NCEP/NCAR 1°×1° reanalysis data.The results show that beore 1730 BST July 12 the stratification was unstable with dry and cold air at the upper level and warm and moist air at the lower level over Nantong,and dry air intrusion and its strong convergence with the warm and moist air in the boundary layer induced the release of unstable energy and the formation of tornado.Based on the numerical simulation results,parameters IBCAPE,ICIN,INCAPE,IEHI and ISWEAT etc are calculated,and it is found that the parameters and indexes were good indicators for the severe weather including this tornado.