Squalls and Tornadoes over the European Territory of Russia on May 15, 2021: Diagnosis and Modeling
А. V. Chernokulsky, Andrey Shikhov, Igor Azhigov, Nadezhda Eroshkina, Daniil Korenev, A. V. Bykov, N. A. Kalinin, M. V. Kurgansky, Yu. B. Pavlyukov, A. A. Sprygin, Yulia Yarinich
Abstract
Abstract Peculiarities were studied of formation of severe convective events, including a long-lived squall and several tornadoes observed over the European territory of Russia on May 15, 2021. The event became one of the most destructive in the forest zone of the region over the past 35 years, with the total area of stand-replacing windthrows exceeding 152 km2. The event was formed at a relatively low moisture content, but other conditions were exceptionally favorable for the formation of strong squalls and tornadoes characterized by a combination of high convective instability and strong wind shear. This resulted in the formation of several supercells and a mesoscale convective complex. The characteristics of cloud systems that caused squalls and tornadoes were analyzed based on satellite and radar data. Several characteristic signatures were identified at the cloud top, including long-lived overshooting tops that coincide with the area of destruction. The maximum reflectivity in some clusters exceeded 60 dBZ, the presence of a mesocyclone was noted in the radial velocity field during the tornado generation. Numerical experiments were performed to reproduce the event using the WRF regional atmospheric model with different initial conditions, which, however, cannot be considered successful.