PRESTO: Precipitation Structures over Orography

Banded precipitation structures over Scotland on 19 November 2009 from Met Office radar network (NIMROD). Colours show rainrate in mm/hr.

Dr Suzanne Gray
Dr Andrew Barrett
Dr Jonathan Fairman (Manchester)
Dr Dan Kirshbaum (McGill)
Dr David Schultz (Manchester)

Terrain-locked convective bands have the potential to focus rainfall over localised regions and enhance the risk of flash-flooding. PRESTO aims to gain an understanding of how often these convective bands occur and understand the general environmental conditions that support their existence and control their precise location and persistence. We also aim to identify the physical mechanisms that allow the convective bands to persist for a number of hours and quantify their predictability in numerical weather prediction models. We will use this knowledge to help improve forecasts of localised, persistent convective rainfall. Many recent flooding events in the UK have resulted from quasi-stationary and/or orographically enhanced rainfall (e.g. Boscastle 2004, Carlisle 2005 and Cockermouth 2009) and a better understanding of the physical mechanisms controlling their location, persistence and predictability will help forecast these events in the future.