Weather Alerts: What You Need to Know

Weather warnings are given a color – yellow, orange or red – depending on the impact the weather is likely to have and the likelihood of this happening.

Yellow and orange alerts can represent different impact levels and probabilities. So it is important to read each warning carefully.

The Met Office, which established the National Severe Weather Warning Service in 1988 after the Great Storm of 1987, uses a matrix system to help decide the severity of the warnings, which then helps determine their colour.

A check mark is placed in the box that best corresponds to the impact of the weather and the likelihood of this happening.

In the example above, a yellow warning would be issued. But even if the expected impacts remained the same, as confidence in the likelihood of those impacts increases, the warning would move up one level to the next ‘impact’ box and the warning would turn orange.

However, you don’t need to be able to interpret a matrix system to read and understand a weather warning.

When an alert is sent, the Met Office also sends a card stating; the affected area, shaded in the color of the warning, the time period covered by the warning and a description of the weather and possible consequences.

The BBC will often show a version of this map on television and social media.