National Severe Weather Warning Service

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The National Severe Weather Warning Service (shortened NSWWS) is a service produced by the UK Met Office which informs the public of the United Kingdom of severe weather which may damage the country's infrastructure and endanger lives. It is required for two main reasons; to inform the Ministry of Defence and civil emergency authorities to trigger plans to help protect the public; and to alert the public to make necessary preparations for the weather event, mostly through the media.[1][2]

Types of warnings[edit]

There can be different types of warnings, depending on the severity of the event. Early warnings are warnings of severe or extreme weather that may occur in the next 5 days, while Flash warnings are warnings of severe or extreme weather that may occur in the next few hours.


As of March 2008, the Met Office improved its warning system by adding an extra stage of warning, the 'Advisory'. They have also provided more colours for different stages of warnings to try to make the system clearer for the public.

Severe weather

Green = No warnings issued

Yellow = Moderate risk of severe weather; moderate risk of disruption

Amber (Early) = High risk of severe weather; high risk of disruption

Amber (Flash) = Severe weather is imminent or occurring/expected in the next few hours; very high risk of disruption

Extreme weather

Green = No warnings issued

Yellow = Low risk of extreme weather; low risk of major disruption

Amber = Moderate risk of extreme weather; moderate risk of major disruption

Red (Early) = High risk of extreme weather; high risk of major disruption

Red (Flash) = Extreme weather is imminent or occurring; very high risk of major disruption and COBRA may be involved if in a highly populated area, such as London[3]

New tiers of alert[edit]

Previously, in exceptional circumstances where extremely damaging weather would have occurred, an Emergency Flash Warning would have been issued, for example when a major storm hit Scotland in January 2005.[4] This has now been replaced by the Extreme Weather Warning, under the recent improvements. The other new tier of alert, the Advisory, is associated with the colour yellow and just indicates that the public should be aware of potential severe weather by ensuring they have access to the latest weather forecast.

Media use[edit]

The Met Office primarily use the broadcast media to inform the public of any warnings. The BBC, ITV and Channel 4 are the terrestrial networks that use the Met Office's data, so are the ones that broadcast the warnings (usually through their television services, although the BBC use their radio stations and website as well).[5] In some cases, news companies can also be informed, especially for extreme weather, which can also advise the public of what to do.


External links[edit]