Asymmetric Influence of the North Pacific Victoria Mode on Intense Tropical Cyclone Formation in the Western North Pacific

Abstract This study investigates the asymmetric response of intense tropical cyclone (TC) genesis frequency (tropical cyclone genesis frequency (TCGF)) in the southeastern western North Pacific (SE‐WNP) to the Victoria mode (VM) from 1950 to 2022. We show a significant increase during the positive VM phases but only a slight decrease during the negative VM phases, indicating a nonlinear relationship between intense TCGF and VM. Observational analyses and numerical simulations demonstrate that this asymmetric response is primarily associated with differing effects of positive and negative VM events on environmental conditions, which subsequently affect TC genesis and development. Specifically, during positive VM years, there is a notable positive sea surface temperature anomaly over the SE‐WNP combined with enhanced relative vorticity and weakened vertical wind shear, which creates favorable conditions for intense TC genesis. This study highlights the complex relationship between extratropical climate models and TC activity and has significant implications for predicting intense TCs in the SE‐WNP.