Abstract/Summary

The evolution of Storm Ciarán was different from what is commonly attributed to windstorms affecting northwest Europe. Ciarán initially developed as a diabatic Rossby wave, driven by low-level latent-heat release and with negligible upper-tropospheric forcing. It then crossed the jet stream, intensifying explosively while developing a low-level warm seclusion and producing extreme near-surface winds, including sting jets. Ciarán is an example of an extreme windstorm following this pathway and highlights the need of a systematic assessment of its relevance in our warming climate.