An analysis is made of a severe storm occurred on 17 July 2009 in the Shandong peninsula by using the 〖WTBX〗V3θ〖WTBZ〗 chart based on the analysis software of MICAPS (3rd edition). The results show that the 〖WTBX〗V3〖WTBX〗θ〖WTBZ〗 chart can reveal the signs of severe storms. The ultralow temperature at the tropospheric top, cold air intruding into the middlelevel troposphere, the caused severe convection, and abundant moisture at lower levels are the causes of the severe storm. The 〖WTBX〗V3θ〖WTBZ〗 charts of the upstream stations can be used to estimate the direction and intensity of moisture transport. The difference in the underlying surface between sea and land is also an important cause of the severe storm. The characteristics of the 〖WTBX〗V3θ〖WTBZ〗 chart are useful in forecasting severe storms more than 12 hours in advance.