Understanding mechanisms for trends in Sahelian squall lines: Roles of thermodynamics and shear

Squall lines dominate rainfall in the West African Sahel, and evidence suggests they have increased intensity over recent decades. Stronger wind shear may be a key driver of this trend could continue to strengthen with climate change. However, global numerical models struggle capture role for organised convection, making predictions changing intensities Sahel uncertain. To investigate impact possible future environmental changes, isolate thermodynamic effects from effects, idealised squall line simulations were initialised profile representative present day: was then modified using trends reanalyses projections. Increased led storm rainfall, but changes dominated shear. Simulations initiated profiles produced shorter?lived storms, likely due convective inhibition absence large?scale convergence or synoptic variability model. A theoretical model based on relative inflow convectively unstable air moisture found predict bulk characteristics storms accurately, including mean rain rates area?averaged maximum vertical velocities, explaining is not prognostic tool as dependent speed, which remains free parameter. The study shows importance long?term highlights need include extreme rainfall.