A thunderstorm warning will be in effect from 11am today amid Storm Antoni.

The storm, the first to be named by the Met Office this season, is expected to bring wind and rain to parts of the UK on Saturday.

The southwest of England, and Wales, looks set to be the most significantly impacted area, with an amber warning for wind, but Watford falls within a yellow warning for thunderstorms in the southeast.

A yellow warning for wind in the southwest came into effect at 8am and the other warnings will all start from 11am.

The warning including Watford ends a 10pm.

The Met Office issues yellow warnings when it is likely that the weather will cause some low level impacts, including some disruption to travel in a few places.

An amber warning means there is an increased likelihood of impacts from severe weather and people should consider changing plans and taking action to protect themselves and their property.

Met Office chief meteorologist Steve Willington said the storm will bring “potentially disruptive” weather as it moves from west to east.

The RAC’s Rod Dennis added: “We expect Saturday to be the worst day on the roads of the summer so far, especially for anyone in the south-west of England – and that’s a lot of people as our research shows it’s the most popular part of the country for leisure trips by car this year.

“Conditions will be atrocious with a wholly unpleasant mix of very strong winds and locally intense rainfall.

"The best advice is to slow down significantly to stay safe and avoid exposed moorland and coastal routes until the storm passes.”

A weather warning for heavy showers and thunderstorms on June 12 was borne out as flooding cancelled trains and forced police to close roads.

Watford Observer: Balmoral Road on June 12Balmoral Road on June 12 (Image: Contribution)

Herts Police were inundated with “a high volume of 999 emergency calls involving cars being stuck in flooded roads in Watford”.

Some roads including Radlett Road, Bushey Mill Lane, the A41, and Balmoral Road began to look “like canals” as the water covered them.