Schematic illustration of the shear-induced convective asymmetry observed in Hurricanes Jimena and Olivia.

Schematic illustration of the shear-induced convective asymmetry observed in Hurricanes Jimena and Olivia. The low-level environmental flow is indicated by the large gray arrow. Upper-level flow is indicated by the three cyan arrows. Convective cells form somewhat upwind of the downshear side of the eyewall. They advect around the eye into the semicircle to the left of the shear vector where warm rain processes generate hydrometeors large enough to reflect radar effectively. Precipitation-driven downdrafts begin about 90o to the left of the shear vector. By the time the cells reach the upshear side of the eyewall they have ascended through the 0oC isotherm and downdrafts predominate below 6 km. As the cells move into the semicircle on the right of the shear vector, most condensate freezes or falls out of the active updrafts. The unloaded updrafts accelerate upward. They detach from the eyewall and approach the tropopause as they rotate through the semicircle to the right of the shear.