Statistical characteristics of sea-effect snow events over the western Black Sea

In this study, the structural classification of sea-effect snow (SES) events occurring over the western Black Sea was made for the period between 2009 and 2018. The main purpose of this study is to determine the meso- and synoptic-scale structures of SES events for the region and to form the basis for nowcasting and forecasting applications. Aviation reports published by four airports in the Marmara Region were analysed, and snowy periods were found. Then, SES bands detected by visual evaluation of satellite and radar images were followed temporally and spatially. Finally, SES events were classified by considering the inland extensions of SES bands along their trajectories, the snowfall conditions in the regions where they pass, and the meso- and synoptic-scale systems affecting snowfall. A total of 95 events were identified. Of these events, 36 were determined as Black Sea (BS) events (38%), 24 were Synoptic-scale (SYNOP) events (25%), 23 were Over Sea Convergence (OSC) events (24%) and 12 were Transition (TRANS) events (13%). The mean duration of the SES events was 15.9 h. The longest event occurred in the SYNOP-Events type and lasted 59 h. It was found that SYNOP-Events lasted longer on average than others. The prevailing wind direction was northerly (NW, N, NE), except for OSC-Events. An inversion layer was detected in most of the BS-Events and SYNOP-Events, and average temperature differences between the sea surface (SS) and the upper level air (850/700 hPa) were approximately 4 °C to 6 °C above the threshold values presented in similar studies in the literature. In the annual statistical analysis, the greatest number of the events was 20 in 2016, no events occurred in 2009 and only two events occurred in 2012. No trend was found on an annual basis. On a monthly basis, the greates number of the events occurred in January (51), while the least events occurred in March (2).