A Synoptic-Scale Perspective of Heavy Rainfall over Chennai in November 2015

Abstract

he South Indian city of Chennai experienced three phases of heavy rainfall that resulted in devastating flood during November and early December of 2015. We find that propagating convective systems from the west Pacific Ocean intensified further over the warm Indian Ocean before moving north towards Indian land region. This northward propagation was guided by two highs of mid-troposphere to the east and west of the Indian region. While the high to the east was typical of an El Niño year, that the west was associated with global phase shift of upper tropospheric Rossby wave. Similar highs to the west were present during other years of heavy rainfall along the east coast of peninsular India.