Data from the Met Office's Cyclone Database, consisting of flat files from the database covering 2000-2005 with associated charts. The database holds lists of cyclones, their types and structural information about each cyclone and associated features as derived from analysis of the UK Met Office Unified Model.

Accurate prediction of severe weather events is a key Met Office goal. As cyclonic systems are responsible for the vast majority of these events, accurate cyclone prediction is also high priority. Although huge strides have been made in numerical weather prediction (NWP) in recent years, cyclonic systems continue to pose problems for numerical models.

Three "exceptional" depressions in the Christmas periods of 1997 and 1999, and another in early December 1999 were all poorly forecast by most of the world's operational models, indicating that there is plenty of scope for improvement. The rationale for constructing a cyclone database (previously called the "Frontal Wave Database") is described in detail in Hewson (1998b). The main motivation was the identification and representation of systematic model biases in new formats which, from most practical perspectives, represent a notable improvement on more traditional r.m.s. error based statistics. Evidently improved knowledge of cyclone forecast characteristics will be valuable not only to the NWP community, but also to forecasting, in part because operational practice now involves using "Field Modification" software to prepare forecast charts (Carroll, 1997), which can be used to correct for known biases.