Tropical Cyclone Outer Size Impacts the Number and Location of Tornadoes

There remains no consensus on whether the outer size of the tropical cyclone (TC) wind field impacts tornado occurrence. This study statistically examines the relationship between TC outer size with both the number and location of tornadoes using multidecadal tornado reports, a reanalysis-derived TC outer size metric, and radiosonde data. These results show that larger TC spawn tornadoes that are located farther from and over a broader region relative to the cyclone center, although these changes do not entirely scale with TC outer size. Larger TCs are also associated with more frequent occurrence of tornadoes per 6 h, especially enhanced numbers of tornadoes. These changes in tornado occurrence in larger TCs may be due to a broadening of favorable helicity for tornadoes in the downshear sector, which may be partially offset by CAPE reductions in the left-of-shear quadrants.