This study provides a novel Lagrangian perspective on cyclogenesis grounded in atmospheric energetics. While the energetics framework is commonly used to understand the planetary scale circulation, its application to synoptic scales is less explored. The authors establish a close connection between extratropical baroclinic zones and local available potential energy, and further analyze air parcel trajectories to link conversions between potential and kinetic energy to specific features of the developing cyclones. The results of this study offer insights into the local, synoptic and large scale contributions to cyclogenesis that are relevant for diverse disciplines in atmospheric and climate sciences.

High-impact medicanes, like Ianos September 2020, are occasionally poorly predicted by operational numerical weather prediction models, and it is therefore very important to understand the factors that limit their predictability and to eventually improve predictions. The well-written study by Pantillon et al. investigates simulations of medicane Ianos performed with 10 model setups, using different models, horizontal grid spacings, and representations of moist convection. Their results highlight the critical importance of a high-resolution representation of moist convection, and the coupling of convective and baroclinic processes in the cyclogenesis phase of the medicane. These results from the major modelling undertaking in this study have important ramifications also for practical forecasting.