CHMI Forecasters Supported by a Team of Convective Experts

A special team of forecasters – the Convective Group (CG), largely trained by ESSL Testbeds, was appointed at CHMI to improve the prediction and nowcasting of convective storms. We bring the experience and lessons learned from the first, pilot season of the CG operation. A decision-making process, data availability, and communication was the most demanding part of our supporting shifts, which we will show in a few case studies from 2022. The CG has established new criteria for different levels of severe storm warnings, including the expected storm structure. CHMI issues thunderstorm warnings one or two days in advance for a larger area, where is a higher chance for severe storms. Later, tens of minutes before the severe storm occurrence, a warning is issued (manually) with 100% probability that the given area will be affected. The CG works as an advisory body for the forecasters on duty, who issue the actual warnings. The scope of other activities is wide, the CG trains forecasters before the summer, also proposed the use of drones for damage surveys (e.g. downburst, tornado, or flash flood). During the season, we were in close contact with the forecasters on duty during days when storms were expected. Concurrently, we were immediately in contact with the public/media and informed about imminent danger, uncertainty, or summary of recent events through the CHMI social networks. We received a lot of positive feedback, which was very encouraging. Inspiration from other national weather services is very welcome.