Storm Betty is set to bring strong winds and heavy rain today as a yellow weather warning has been issued for parts of the UK.

It comes as more than half a month’s rain could fall across the south of England on Friday, which could lead to “a few homes and businesses” being flooded, the Met Office has warned.

Britons could end up soaked because 30mm to 40mm of rain is expected to fall in some spots in just six hours, the forecaster said.

A yellow warning for wind is in place across coastal areas of north and mid-Wales between midnight and 6pm on Friday – and gusts could reach up to 60mph.

The area affected covers London as well as the whole of the South East and the Solent area, stretching to Birmingham at its northernmost edge.

Buildings and structures could be damaged by flooding and lightning strikes while homes could also lose power “for a short time”. The Met Office said trees could fall down leading to train cancellations and likely delays.

Met Office Chief Meteorologist Jason Kelly said: “Friday and Saturday will see unseasonably wet and windy conditions for much of the UK. While Storm Betty will have higher impacts in Ireland, exposed Irish Sea coasts of the UK could see gusts in excess of 70mph, with around 50mph more widely.

“Storm Betty is also bringing some large accumulations of rainfall for the time of year, with some spots of Northern Ireland seeing around 80mm of rain, though between 15-25mm is expected more widely. Parts of Scotland could see similarly high accumulations, especially over higher ground.”

Holidaymakers beginning their summer getaway are advised to check the Met Office app and social media channels for updates and brace themselves for longer journey times.

A yellow weather warning for thunderstorms has been issued by the Met Office for large parts of the South and the West Midlands between 6am and midday on Friday.

Marquees and tents that may be used by campers in Snowdonia could also fall down in the gusts while caravans and lorries may struggle on some roads.

Homes could also lose power for a short time in affected areas, the forecaster warned.