Dynamic and thermodynamic contribution to the October 2019 exceptional rainfall in West Central Africa

Exceptional rainfall hit West Central Africa in October 2019. We analyzed regional moisture and Moist Static Energy (MSE) budgets to understand the underlying mechanisms, focusing on dynamic and thermodynamic effects. The moisture budget analysis revealed that precipitation anomalies were primarily driven by dynamic effects. In the north of the region, horizontal moisture advection induced by horizontal wind anomalies dominated, while vertical moisture advection was key in the south. Thermodynamic effects, though secondary, contributed up to 35% in the north and 15% in the south. The MSE balance showed that anomalous vertical motion was dominated by dynamic effects in the north, particularly wet enthalpy advection induced by horizontal wind anomalies. West of the Congo Basin, increased net energy balance was the primary driver of vertical motion changes. Horizontal and vertical MSE advection appeared less significant. Strong MSE balance anomalies in the north were linked to its meridional component, especially meridional wind anomalies in the dynamic effect and meridional latent heat anomalies in the thermodynamic effect. Our findings suggest that both dynamic and thermodynamic effects must be considered to adequately anticipate such extreme events. Understanding these mechanisms could enhance forecasts and projections, ultimately improving the region's resilience to extreme weather.