The UK's weather service has warned of sudden flooding and thunderstorms for parts of Sussex this weekend.

A yellow severe weather warning has been issued for much of the south coast including West Sussex where experts predict "active" thunderstorms with up to 75mm of rainfall.

It comes as warm, humid air comes from the south east causing big storm clouds to develop overnight and into Sunday.

Flooding in Worthing in July during a previous yellow warningFlooding in Worthing in July during a previous yellow warning (Image: Sussex News and Pictures)

There are fears the stormy conditions could cause power cuts or dangerous conditions on the roads - and the Met Office has issued safety advice to those who must go outdoors.

Meteorologists say that, if storms develop, 30 to 40mm of rain may fall in less than an hour - but some places may see more than 75mm.

The storm is expected to travel north as the day continues, with the yellow warning in place from 4am until 9pm. Only West Sussex is predicted to be affected.

Met Office deputy chief meteorologist Dan Harris said: “Through Saturday night and into Sunday we’ll see a gradual change in our weather across the UK with an increasing chance of heavy thundery showers developing, particularly across central parts of the UK.

"Should they develop there is the risk of some local disruption from intense rainfall, gusty winds, lightning and possibly hail too.

"Not everywhere within the warning area will see thunderstorms, and confidence in any individual location being affected remains extremely low at this time.

“The risk of thunderstorms steadily transfers northwards through Sunday afternoon and into the early evening.

"If you have plans for Sunday, I’d recommend keeping up to date with the Met Office forecast and any updates to the warnings.”

As the week continues, the weather will become more unsettled with spells of rain and showers in places due to the high pressure moving eastwards.

The Met Office told the public to expect spray and sudden flooding to cause disruption on road and rail. There is also a slight of power cuts.