• tornadoes;
  • tropical cyclones

[1] A statistical model for tornado frequency from Gulf of Mexico landfalling tropical cyclones (TCs) is developed using TC size, intensity, recurvature, and mid-level specific humidity data. New datasets are assembled for tornado frequency and for TC size at landfall as measured by the radius of outer closed isobar and distance of tornado from the TC center. Owing to systematic undercounting of tornadoes, the model is used to reconstruct the TC tornado climatology back to 1948, and further back to 1920 using a modified model that does not include mid-level specific humidity. Relative to the previous active period for Gulf TC landfalls of 1948–1964, the active period since 1995 has seen a statistically significant increase (95% level) in median TC tornadoes and in the frequency of large TC tornado outbreaks. These changes are linked to an increase in the median size and frequency of large Gulf landfalling TCs.