HEAVY rain and thunderstorms are possible across large swathes of Wales this evening as the Met Office issues a yellow weather warning.

The warning, which comes into effect from 6pm on Tuesday until midday Wednesday, stretches the length of Wales, but misses out Pembrokeshire and a large part of Gwynedd.

The Met Office says: "Areas of heavy rain are expected to develop and push north across the warning area.

"Rain will develop in southwest England late afternoon, before becoming heavier and expanding north on Tuesday evening and overnight into Wednesday.

"Many places will see around 10-20 mm of rain, but there is a chance some locations may see considerably more than this over a six hour period, most likely parts of southwest England and south Wales.

"A few places may see 50-80 mm of rain fall in six hours. Isolated thunderstorms are also possible in the south of the warning area, with lightning an additional hazard."

The rain could lead to travel disruption and some flooding, with a small chance of power cuts.