Thunderstorms coming up against the wind on 11 June 2023 – the development of a mesoscale convective system over southern England

On 11 June 2023, a mesoscale convective system (MCS) developed over the southern UK producing heavy rainfall and numerous lightning strikes. The MCS formed from clusters of relatively small‐scale thundery showers south and west of the London area. These showers then merged together and grew upscale to form an organised convective system of the leading‐line trailing stratiform type with a large quasi‐circular cloud shield. Both surface‐based and elevated convection appears to have been involved. Heavy rainfall caused localised surface water flooding with a number of stations in southern England reporting event totals in excess of 1 inch (25.4mm).