A derecho in northern Europe

A mesoscale convective system (MCS) producing a derecho impacted four European countries 16-17 October 2022. The MCS produced high wind gusts and wind damage that started over Denmark, continued over Sweden, Estonia and Finland, along 1300 km long path. The MCS formed a large-scale bow echo that travelled through dense observation network over southern coastal waters of Finland resulting in detailed measurements of storm passage over surface observation stations, an observation mast and three radars. In Finland the maximum gust observed was 39,2 m/s, and storm-scale (≥25 m/s) wind gusts were observed on 16 surface observation stations. Wind measurements showed that the duration of storm-scale wind gusts were approximately 18 minutes and the maximum wind gusts (above 30 m/s) lasted approximately 10 minutes as the bow echo moved over observation stations. This unique observation data gives us insight to wind speeds and their duration in a derecho. The focus of this study is on comparison of radar observations of the MCS to the measurements from the surface observation network such as maximum wind gusts, temperature and cold pool strength, and change in the surface pressure. The synoptic and mesoscale environment is also described. The unusual seasonal time of the event caused extra challenge in its forecasting.