Asymmetric Rainband Processes Leading to Secondary Eyewall Formation in a Model Simulation of Hurricane Matthew (2016)

Abstract The dynamics of an asymmetric rainband complex leading into secondary eyewall formation (SEF) are examined in a simulation Hurricane Matthew (2016), with particular focus on the tangential wind field evolution. Prior to SEF, storm experiences axisymmetric broadening as stationary downshear quadrants intensifies. acceleration pattern that causes this is inward-descending structure positive nearly 100 km wide radial extent and maximizes low levels near 50 radius. Vertical advection from convective updrafts downshear-right quadrant largely contributes low-level maximum, while broader due horizontal within stratiform precipitation downshear-left quadrant. This broad slantwise mesoscale descending inflow (MDI) driven by midlevel cooling regions draws absolute angular momentum inward. MDI further revealed examining irrotational component velocity, which shows extending downwind upshear-left Here, connects boundary layer, where new triggered along its inner edge; these found be important subsequent axisymmetrization maximum incipient eyewall.