National Severe Weather Warning Service web page

New dawning for warnings

28 February 2011

Changes to our National Severe Weather Warning Service will make our warnings even more effective. Pat Boyle, Public Weather Service Assurance Manager, describes the new National Severe Weather Warning Service.

The National Severe Weather Warning Service (NSWWS) was set up in 1988 following the Great Storm to save lives and property. In 2009, the Public Weather Service Customer Group asked the Met Office to review the service by consulting the public and emergency responders.

Through public focus groups, surveys and emergency responder workshops, we found that warnings should be impact-based, describing the likely impacts of the weather. The need for improved communications was also identified, making the language simple and easy to understand. Graphical presentation of the warnings also needed attention, with a need for 'risk of disruption' maps on our website.

From the end of March 2011, our warnings will provide a combination of the potential impact the weather will have and the likelihood of the weather happening. We've worked with partner agencies to develop a risk matrix to assess the impact severe weather might have. This assessment will take into account geographical factors - for example, will wind have the same impact in the north-west Highlands as in South East England?

The assessment will also consider how unusual the severe weather is, bearing in mind the recent weather. After strong winds, for instance, lower wind speeds might be more significant than usual due to structures being weakened. For rainfall, we'll discuss flooding impacts with the Flood Forecasting Centre in England and Wales and the Flood Forecasting Service in Scotland to ensure consistent assessments.

We'll continue to assess the likelihood of severe weather using our computer models combined with the Chief Forecaster's skill. A colour will be assigned to the warning which is a combination of potential impact and likelihood. Traffic light colour-coding, introduced into our warning system a few years ago, will remain with the same general messages. An assessment from the Chief Forecaster will explain in clear language why a warning has been assigned a particular colour and if there is any uncertainty, for example, in timing or location.

The weather never sleeps, so it's possible for alerts and warnings to be issued at any time of day, although every effort will be made to issue them during normal working hours. Changes to the NSWWS should make our warnings even more useful. One thing is for certain, the new service will continue to be vital to safeguard lives and property.

Easy to see

We're making our severe weather warnings easier to understand. Currently, severe weather warnings are shown on our website by colouring whole counties with the appropriate colour of the warning. The new system will show a polygon around the area most likely to be affected. This will make it easier to see - particularly for larger areas - the more vulnerable locations.

National Severe Weather Warning Service web page

Clearer web pages will show multiple warnings for different weather elements at a glance, using symbols for different weather elements. Icons will indicate the type and severity of warnings. Visitors to our website will be able to navigate using both map and tabular list. Animations will help to see warnings evolve and a zoom functionality will make it easy to distinguish between parts of counties or local authority areas.

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