NATIONAL weather forecaster, The Met Office, has extended a yellow weather warning into Monday.

The Met Office issued a yellow weather warning for thunder across parts of South Wales on Sunday, September 1, and has now extended the yellow warning until Monday, September 2.

A spokesperson for the Met Office, said: "On Monday, areas of heavy showers and thunderstorms are likely to be ongoing from overnight and expected to continue to affect parts of the UK through the day.

The updated weather warning is now expected to cover a larger area of South Wales.The updated weather warning is now expected to cover a larger area of South Wales. (Image: Met Office)

"The focus for thunderstorms and impacts is expected to gradually move east later in the day."

According to the forecaster, the updated yellow weather warning will now affect a larger part of South Wales than previously forecasted.

Areas which may be affected by potential thunderstorms, heavy rainfall, and flooding, are as follows: 

  • Blaenau Gwent

  • Caerphilly

  • Cardiff and the Vale of Glamorgan

  • Monmouthshire

  • Newport

  • Torfaen

The updated weather warning is now expected to cover a larger area of South Wales.The updated weather warning is now expected to cover a larger area of South Wales. (Image: Met Office)

Travel disruption

Spray and sudden flooding could lead to difficult driving conditions and some road closures, said the weather forecaster.

Some trains and bus services may be affected if there is heavy flooding or lightning strikes.

The Met Office has said there is a chance that power cuts could occur and other services to some homes and businesses could be lost.

The updated yellow weather warning is now expected to cover all areas of Gwent (Newport, Blaenau Gwent, Monmouthshire, Torfaen and Caerphilly) as well as the Vale of Glamorgan (Barry and Penarth)The updated yellow weather warning is now expected to cover all areas of Gwent (Newport, Blaenau Gwent, Monmouthshire, Torfaen and Caerphilly) as well as the Vale of Glamorgan (Barry and Penarth) (Image: Met Office)

Flood alerts

No flood alerts are in place according to the Natural Resources Wales website, though there is a chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.

A spokesperson for the Met Office, added: "The extent of these thunderstorms remains very uncertain and whilst many places will miss them, some places may see 30 to 40 mm of rain fall in less than an hour and perhaps over 60-80 mm in one or two places.

"Frequent lightning strikes and hail will be additional hazards."