Storm Aila : An unusually strong autumn storm in Finland.

In order to assess how well ERA5 and IFS represent the real, observed wind speeds during storm I Aila i , Figure 7 shows the time series of maximum wind gust speed at two stations: Pietarsaari Kallan (Figure 7a) and Rauma Kylmäpihlaja (Figure 7b). Therefore, we can conclude that storm I Aila i had the strongest wind speeds and wind gusts out of all Septembers in the observation record in 2004-2020 and in ERA5 in the period 1979-2020. The dashed vertical line denotes the maximum wind speed or wind gust in the chosen dataset. gl Furthermore, when the maximum wind speeds in all marine and land stations in Finland (excluding mountainous stations which are located over 200 m above sea level) during the whole observational history are considered, no higher September wind speeds are found (not shown). The winds caused by storm I Aila i were analysed using wind speed and wind gust observations from FMI's weather stations located across Finland. [Extracted from the article]