On the intensity and destructive potential of a past extreme, synoptic storm in a future warmer climate

Abstract. The global climate is undergoing significant changes, with rising greenhouse gas concentrations driving increased temperatures, altered precipitation patterns, and sea level rise. Yet, the full implications for mid-latitude storm systems remain an area of active investigation. This study examines how such storms may intensify under future warming, focusing on Storm Anatol, which severely impacted Denmark on 3 December 1999. Using the high-resolution weather prediction model HARMONIE-AROME and a pseudo-global warming (PGW) framework, the storm is simulated under a range of thermodynamic conditions representative of a warmer climate.

Results show a clear warming signal, with increased near-surface temperatures and atmospheric moisture contributing to stronger storm dynamics. Wind and gust speeds rise systematically with temperature, while the spatial extent and duration of damaging wind conditions also expand. To quantify these changes, we introduce the Cumulative Wind Exposure Index (CWEI), which captures the integrated spatial and temporal severity of wind exposure.

Application of CWEI reveals a marked increase in cumulative wind exposure in warmer scenarios relative to the historical case. When linked to established wind-damage relationships, this translates to substantially higher potential for structural damage and disruption. These findings suggest that storms like Anatol, already destructive in the past, are likely to become even more damaging under future climate conditions. This underscores the need for climate-resilient building standards, improved early warning systems, and long-term adaptation strategies across northern Europe.