Mesoscale convective systems (MCSs) produce over 50% of tropical
precipitation and account for the majority of extreme rainfall and
flooding events. MCSs are considered the building blocks of larger-scale
convectively coupled equatorial waves (CCEWs). While CCEWs can provide
favorable environments for convection, how CCEWs can systematically
impact organized convection and thereby MCS characteristics is less
clear. We examine this question by analyzing a global MCS tracking
dataset. During the active phase of CCEWs, MCS frequency increases and
MCSs rain harder, produce more lifetime total rain, and grow larger in
size. The probability of extreme MCSs also elevates. These changes are
most pronounced when MCSs are associated with Kelvin waves and tropical
depression-type waves while least so with the Madden-Julian Oscillation.
These results can be benchmarks to improve model representation of MCS
interactions with large-scale circulations and can be leveraged
operationally for extended forecasts of high-impact MCSs.