Forecasting disruption due to convection within UK airspace

Thunderstorms and cumulonimbus (Cb) clouds result in an increased workload for air traffic controllers as aircraft divert around hazardous zones and can result in delays and/or cancellations for air travellers. The London Terminal Manoeuvring Area (LTMA) is one of the busiest airspace sectors in the world and its constituent airports are therefore highly susceptible to delays caused by Cb cloud and thunderstorms. In response to this, since the summer of 2012, the Met Office has provided a forecast of the risk of thunderstorms and deep convection within the LTMA to the National Air Traffic Service (NATS) in order to aid their management of any disruptive systems in the area. Advance warning of thunderstorm activity and Cb clouds in a particular area enables NATS to reduce disruption, by altering air traffic capacity prior to the event.

This poster discusses the development of the LTMA Thunderstorm Risk forecast. We discuss forecast accuracy using case studies from summer 2013. The resulting forecaster guidance issued details key factors relevant to assessing the impacts of convection on Air Traffic Management (ATM). Finally we discuss the development of an objective verification system for the service and some of the challenges faced in doing this. As a result of implementing the forecast service, NATS have been able to reduce disruption in the LTMA through improved planning in advance of a convective event.