Mesoscale convective systems (MCSs) over tropical Africa and the Atlantic provide critical rainfall while posing flood risk, and, when coupled to African easterly waves (AEWs), often serve as precursors to Atlantic tropical cyclones. This talk presents a storyline perspective on how these tropical weather systems respond to a warming climate using convection-permitting regional simulations with the Model for Prediction Across Scales–Atmosphere (MPAS-A), organized in three parts.

First, I present results from recently published studies using 3-km convection-permitting MPAS-A simulations of September 2006 convective activity under present and pseudo-global-warming (PGW) future climate conditions. Using objective AEW and MCS tracking algorithms, we show how MCS and AEW characteristics change in response to a warming climate: despite increased convective available potential energy (CAPE), future MCS numbers decrease due to substantial increases in convective inhibition (CIN), while both organized and disorganized MCSs show increased rainfall — more so over water than over Africa, linked to future relative humidity increasing over water and decreasing over land. Future MCSs also shift southward, moving eastward over Africa and westward over the Atlantic, becoming less tied to the African easterly jet and more closely linked to the West African monsoon and AEWs, with the most extreme future MCSs showing stronger updrafts and downdrafts and a drier mid-to-lower troposphere. Together, these results suggest that synoptically forced MCSs — such as those coupled to AEW dynamics — evolve differently from the thermodynamic evolution expected across the general MCS population under warming, an outcome only capturable with kilometer-scale modeling.

Second, I present preliminary results from ongoing multi-year MPAS-A storyline simulations funded by NSF AGS-2508342, extending this single-event framework to multi-year historical and future JJAS seasons targeting different ENSO phases, to understand how the mean tropical climate, MCSs, and AEWs over Africa and the Atlantic — and their ENSO-phase-dependent behavior — respond to warming by end of century.

Third, I discuss work done as co-lead and in collaboration with the Mesoamerica and Caribbean Affinity Group (MAAG), an NSF NCAR and community affinity group effort focused on community engagement, data access, and fostering collaboration between researchers across sectors as an international platform. I will highlight research outcomes and working-groups planning.. RAL events page