A crowding of isentropes indicates an air mass boundary and a baroclinic zone. Though similar to fronts, the cloud band of the Baroclinic Boundary shows no front like appearance in a vertical cross section. The appearance is similar throughout all types of Baroclinic Boundary.

• Isentropes (equivalent potential temperature):
  • Zone of high gradient of equivalent potential temperature, gradient mostly weaker than in fronts
  • Flat decline of crowded isentropes - a distinct difference from a front
  • Superadiabatic stratification only at low levels (associated with diabatic heating or cold air advection)
• Divergence:
  • Zone of convergence within the highest gradient of isentropes, usually weaker than within a frontal zone
• Vertical motion (Omega):
  • Upward motion within the gradient zone indicating ascent, but usually weaker than in a frontal zone
  • All cases show weak ascent at middle levels

Isentropes (equivalent potential temperature)

Divergence

Vertical motion (Omega)