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Weather explainer: Watch for thunderstorms

12:00
10 April 2023

Weather explainer
Watch for thunderstorms

Lightning

Across the UK and Ireland, thunderstorms are in the forecast, but how do they actually develop?

They begin to form when warm air lies under colder air in an unstable atmosphere. The warm air will then rise quickly and condense into water droplets to form a cumulonimbus cloud.

Within the cloud, the warm air and water droplets continue to rise and will eventually freeze into positively charged ice crystals. When the ice crystals are heavy enough, they begin to fall as hail.

As the hail falls, it becomes negatively charged. The negatively charged pieces of hail at the base of the cloud then become attracted to the positively charged Earth's surface.

When the attraction is strong enough, the charges come together creating a flash of lightning. It is the rapid expansion and heating of the air which causes the claps of thunder.

Watch our weather explained video below to find out more about how thunderstorms develop:

Weather & Radar editorial team
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