Revealing atmospheric Von Kármán vortex street past a severe thunderstorm

The atmospheric von Kármán vortex street (VKVS) is a periodic series of turbulent shedding vortices that form in the wake of topographic obstacles and influence the dynamics of the lower atmosphere. The present study demonstrates that such structures can also form downwind of a strong thunderstorm, which acts as a fluid obstacle to the tropospheric wind. A detailed multiplatform observation dataset is analyzed to identify an atmospheric VKVS past an extreme convective storm that occurred over the Mediterranean Sea in 2015. The dataset is then utilized to set up a high-resolution large-eddy simulation to numerically reproduce the VKVS under simplifying assumptions, which accounts for the essential dynamical features of a convective updraft in a tropospheric cross flow. It is proven that the interaction between the thunderstorm updraft and the tropospheric wind produces a regular pattern of shedding vortices, extending in the entire troposphere and persisting for long distances downwind. The generation mechanism is described, and a peculiar entrainment of momentum and energy from the updraft is revealed. The shedding vortices exhibit high peaks of wind speed and turbulent kinetic energy in the low troposphere and enhance heat and mass transport in both vertical and downwind directions. Overall, the VKVS can be categorized as a self-sustained convectively induced turbulence structure, extending the influence of thunderstorms beyond the usual ranges.