Some notes on baroclinic instability:

• random initial conditions evolve in time to the become dominated by the most unstable mode.
• localized disturbances develop as extratropical cyclones are observed in nature.
• localized disturbances move downstream at the group speed
• nonlinearity slows and eventually stops development
  • vertical tilt decreases
  • surface low moves poleward
• in pressure, growing disturbances tilt westward with height and decay disturbances tilt eastward with height