Schematic illustration of the secondary flow around the eye of a hurricane. The eyewall cloud is gray with a blue frictional indraft feeding the buoyancy-driven, primary updraft and outflow. The saturated convective downdrafts in the eyewall are dark green, and the evaporatively driven descent along the inner edge of the eyewall is brown. Both downdrafts feed moist air into the volume below the light green inversion surface. The vertical yellow arrows are the dynamically driven descent inside the eye, and the horizontal, curved ones are entrainment into the eyewall. Balance between moist inflow and loss by entrainment to the eyewall determines the rate of rise or fall of the inversion surface.