A saturated lapse rate insures latent heat will be released at a maximum rate. Hurricanes are warm core storms. The heat hurricanes generate is from the condensation of water vapor as it convectively rises around the eye wall. The lapse rate must be unstable around the eyewall to insure rising parcels of air will continue to rise and condense water vapor. The fourth and one of the most important ingredients is that of a low vertical wind shear, especially in the upper level of the atmosphere.
Wind shear is a change in wind speed with height.
Strong upper level winds destroy the storms structure by displacing the warm temperatures above the eye and limiting the vertical accent of air parcels. Hurricanes will not form when the upper level winds are too strong. The fifth ingredient is high relative humidity values from the surface to the mid levels of the atmosphere. Dry air in the mid levels of the atmosphere impedes hurricane development in two ways. First, dry air causes evaporation of liquid water.