An analysis of a severe local storm using isentropic trajectories

One and one-half hour isentropic trajectories obtained from an objective computer technique for the 308K, 312K, 320K and 332K isentropic surfaces are investigated for the May 28, 1967, severe local storm case in the National Severe Storm Laboratory (NSSL) network. In conjunction with the trajectories, air parcel properties of vertical motion, acceleration, divergence, vorticity, static stability and total energy have been studied with respect to development, growth, movement and decay of the storm system. Basic assumptions are that the flow is frictionless and adiabatic over the entire grid. The results show that the observed winds do provide some skill in formulating isentropic trajectories which demonstrate the presence of storm activity in the specific region. The investigation of a mesoscale inertial-gravity wave having a wave length of 150 KM, period of 3 hours and phase speed of 14 m/sec is also presented, with its possible correlation to the onset of the severe storm. (Author)