Quasi-geostrophic barotropic vorticity: β-plane wave packets and blocking highs
Rossby waves propagate westward relative to the mean flow with phase speed c = U − β/k². When planetary wavenumber k matches the resonant wavenumber k_s=√(β/U), stationary Rossby waves form and can lock into a blocking high — a persistent anticyclone that deflects the jet stream for days to weeks.