Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-02T23:53:55.994Z Has data issue: false hasContentIssue false

A study of twentieth-century extreme rainfall events in the United Kingdom with implications for forecasting

Published online by Cambridge University Press:  29 March 2004

William H. Hand
Affiliation:
Met Office, Exeter, UK Email: [email protected]
Neil I. Fox
Affiliation:
Telford Institute of Environmental Systems, University of Salford, UK Dept. of Atmospheric Science, University of Missouri – Columbia, USA
Christopher G. Collier
Affiliation:
Telford Institute of Environmental Systems, University of Salford, UK
Get access

Abstract

Rainfall events in the United Kingdom during the twentieth century have been surveyed and those identified as extreme by the Flood Studies Report (1975) standards have been examined for common features. Events of duration up to 60 hours were considered in order to investigate those that could cause flash floods. More than half of the 50 events identified were short-period convective storms. The rainfall events were classified by meteorological situation, location and season, allowing the identification of conditions under which extreme rainfall occurred.

Suitable conditions for extreme rainfall were split into three categories: orographic, frontal and convective. The frontal and convective classes were then divided into two sub-classes according to whether significant embedded instability was present in the frontal cases and the nature of the convection in the convective cases. The study revealed a lot of commonality between the cases. For example, all of the orographic events occurred in winter in moist west to southwest airflows, and 80% of the frontal cases involved a slow-moving depression to the south or east and also a slow moving frontal system. A conceptual airflow diagram has been developed for some of the frontal cases. The key result, however, was the discovery that each category of meteorological situation occupied a unique space in a rainfall amount versus duration diagram for each extreme event. This offers exciting opportunities for applying the results of this study and a framework for studying future events.

Type
Research Article
Copyright
© 2004 Royal Meteorological Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)