Changes in large-scale circulation over the Indo-Pacific region and its association with 2018 Kerala extreme rainfall event

We investigate the characteristics and causes of extreme rainfall event occurred in Kerala (south western regions peninsular India) August 2018. The changes large-scale circulations over Indo-Pacific domain their association with regional circulation features, which made are analysed. During this event, experienced eleven days incessant from 8 to 18 It is observed that these were accompanied two spells during 8–10 14–17 2018 severe floods Kerala. more than 100 mm day−1, particularly south events. triad (average three days) analysis vertical velocity at 500 hPa moisture convergence surface level reveal dynamics thermal structure deep convective activity. A remarkable eastward shift cross equatorial flow Indian Ocean produced an intense offshore vortex, induced towards southern especially where was occurred. west Pacific subtropical high (WPSH) one region, shifted northward flank WPSH extended westward resulting a blocking created East Asia period. cross-equatorial Bay Bengal, outflow Asian mainly maintaining low-pressure system Bengal event. Therefore, key cause flood through intrusion subtropics out Bengal.