Composite mesoscale environmental conditions influencing tornado frequencies in landfalling Tropical Cyclones

Composites containing the strongest LTCs have the strongest maximum 10-m-700-hPa and 10-m-500-hPa BWDs (-20 m s21) with nearby maximum frequencies of TCTs. Corresponding composites containing weaker LTCs but still many TCTs, had bulk vertical shear values that were -20% smaller (-16 m s21). Additional compo-sites of cases having similarly weak average LTC strength at landfall, but few or no TCTs, had both maximum bulk vertical shears that were an additional -20% lower (-12 m s21) and smaller MLCAPE.

TCT environments occurring well inland are distinguished from others by having stronger westerly shear and a west-east-oriented baroclinic zone (i.e., north-south temperature gradient) that enhances mesoscale ascent and deep convection on the LTC's east side.