FIGURE 3.
Schematic representation of tropical cyclogenesis within a “marsupial” wave pouch. Dashed light blue streamlines illustrate the typical inverted‐V flow pattern observed in a stationary (ground‐based) frame of reference. The solid blue streamline delineates the wave pouch as viewed in the frame of reference moving at the same speed as the wave. This closed circulation serves as a protective container for mesoscale vortices, insulating deep convection (shaded gray) from detrimental environmental factors like the dry Saharan Air Layer. Convergent flow allows for the entrainment of environmental vorticity and air through a lateral opening. The core of the pouch—the optimal site for storm development—is defined by the intersection of the trough axis (solid brown line) and the critical latitude (solid purple line) relative to the easterly jet (solid gray line). Adapted from Wang et al. [134].