Changes in extremely severe and higher category cyclonic storms (ESCS), defined as tropical storms with lifetime maximum winds greater than 46 ms −1 , over the North Indian Ocean (NIO) have received considerable attention recently (Mohapatra, 2016;Murakami et al., 2017;Vellore et al., 2020). Storm surge and coastal flooding caused by the increase in ESCS can lead to loss of lives and enormous property damage along densely populated coastal regions (Sahoo et al., 2021). Many of the recent ESCS have been formed in NIO during May. The recent tropical cyclone (TC) Tauktae-2021, super cyclone Amphan-2020 which was the second-largest since Odisha super cyclone-1999, Fani-2019; Mekkunu-2018 have formed recently in NIO during May, while TC frequencies are higher in NIO during the post-monsoon season (October-December). Increasing TC intensity in NIO has implications as Indian Ocean region is densely populated; one-third of the Indian population and majority of the Asian population are located near coastal regions (Senapati & Gupta, 2014). Therefore, understanding the mechanism for increasing frequency and seasonality of ESCS is highly essential.Climatologically, TC in NIO exhibits a bimodal character, TC form during the pre-monsoon (Mar-May) and post-monsoon season, maximum during the post-monsoon season (Mohapatra, 2016;Sikka, 2006). One of the reasons for the higher TC frequency during the post-monsoon season is the decrease in vertical wind shear