Wave Propagation:

Upper level buoyancy waves propagate to the West relative to the mean circulation; whereas lower level waves propagate to the East relative to the mean circulation. Both waves propagate at the same speed and at the right wavelength for baroclinic instability to occur.

Pressure Pattern:

The pressure field tilts westward with height. The upper level trough is behind the surface low in a developing cyclone. If the upper level catches up with the surface low then the system stops developing.

Temperature Pattern:

The temperature field tilts eastward with height. C.f. baroclinic instability by buoyancy anomalies.

Vertical Motion Patterns:

Ascent occurs ahead of the upper level trough (differential vorticity advection for VATA – form of the Omega equation.

Ascent occurs ahead of a surface warm anomaly – warm advection (Laplacian of the thermal advection).

Vertical motion titls slightly westward with height, along with the pressure field.