Effects of surface fluxes on ventilation pathways and the intensification of Hurricane Michael (2018)

The slower recovery contributes to the initial intensity bifurcation between experiments. Radial ventilation has two pathways. At low levels, it is coupled with downdraft ventilation.

Aloft, between heights of 5 and 10 km, it is maximized upshear and associated with storm-relative flow. This pathway is similar for each experiment initially, suggesting that the initial bifurcation of intensity is not a consequence of radial ventilation aloft. Trajectories from radial ventilation during a later time period show the destructive impact of lower-theta(e) air in the near environment on convection upshear and right of shear for the weaker experiment.

This study demonstrates how ventilation pathways at low levels and aloft are affected by surface fluxes, and how ventilation pathways operate, at different times, to affect tropical cyclone development.