Weather warnings are given a colour – yellow, amber or red – depending on the impact the weather is likely to have and the likelihood of it happening.
Yellow and amber warnings can represent a range of impact levels and likelihoods so it is important to read each warning carefully.
The Met Office, which set up the National Severe Weather Warning Service in 1988 following the Great Storm of 1987, uses a matrix system to help decide on the severity of the warnings, which then helps decide the colour.
A tick is placed in whichever box best matches the impact of the weather against the likelihood of it happening.
In the example above a yellow warning would be issued. However, even if expected impacts remained the same, if confidence in the likelihood of those impacts increased, then the warning would move up a level to the next “impact” box and the warning would become an amber one.
However, you do not have to be able to interpret a matrix system to be able to read and understand a weather warning.
When a warning is sent out, the Met Office also sends a map showing the affected area shaded in the colour of the warning, the time period the warning covers, and a description of the weather and potential impacts.
The BBC will often show a version of this map on television and social media.
