We examine diagnostically the structure and spectral energetics of an amplified persistent blocking ridge and trough pattern that occurred in one of the GLAS climate simulations. This particular model simulation was performed by Shukla and Bangaru (1979) to study the sensitivity of the quasi-stationary waves to the North Pacific sea surface temperature anomalies. The spectrally filtered Hovmöller diagram shows that wavenumbers 2 and 3 in the anomaly run become stationary near their climatological locations. The constructive interference of wavenumbers 2 and 3 forms two persistent blocking ridges: one in the west coast of North America and the other in western Europe. Spectral energetics analysis of this blocking case shows that A2I/ and A3, the available potential energy of wavenumbers 2 and 3, are supplied by the conversion from zonal available potential energy. K2 and K3, the kinetic energy of thew two waves, are maintained by different processes: K2 is maintained by conversion from A2 to K2, a baroclinic proem, while K3 is mainly maintained by conversion from Kz, the zonal kinetic energy, to K3, a barotropic process. The model-simulated blocking episode is similar to the atmospheric circulation conditions in January 1963 and the 1976-77 winter. The spectral energetics for thew two periods are compared with those of the model simulation, and in most instances, are found to be quite similar.