Monitoring, cataloguing, and weather scenarios of thunderstorm outflows in the northern Mediterranean

Abstract. High sampling rate (10 Hz) anemometric measurements of the Wind, Ports, and Sea monitoring network in the northern Tyrrhenian Sea have been analysed to extract the thunderstorm-related signals and catalogue them into three families according to the different time-scale of each event, subdivided among 10 min, 1, and 10 h events. Their characteristics in terms of direction of motion and seasonality/daily occurrence have been analysed: the results showed that most of the selected events come from the sea and occur from 12:00 to 00:00 UTC during the winter season. In terms of peak wind speed, the strongest events all belonged to the 10 min family, but no systematic correlation was found between event duration and peaks.

Three events, each one representative of the corresponding class of duration, have been analysed from the meteorological point of view, in order to investigate their physical nature. According to this analysis, which was mainly based on satellite images, meteorological fields obtained from GFS analyses related to convection in the atmosphere, and lightning activity, the thunderstorm-related nature of the 10 min and 1 h events was confirmed. The 10 h event turned out to be a synoptic event, related to extra-tropical cyclone activity.