THUNDERSTORMS could be on the cards on Saturday afternoon following a yellow weather warning being issued for South Wales by the Met Office. 

The warning comes as the weather forecasters are predicting a very warm weekend, with temperatures set to hit the low twenties, around 21 or 22 degrees for much of this weekend. 

Sunday is expected to be the hottest day, with the high temperature being 23 degrees around three to four in the afternoon. 

The Met Office has put the yellow weather warning in place from 1pm to 8pm on Saturday, May 18, and says that the "slow-moving heavy showers and thunderstorms" could lead to potential flooding in some areas. 

While the Met Office has admitted that not everywhere is likely to be hit, the weather warning is covering the majority of South Wales, including Gwent and Cardiff, as well as some of England just over the border, including Hereford and Ross.

Despite the prediction of thunder and heavy rain, there is still some hope of some spells of sunshine throughout the day. 

The Met Office forecast for Saturday says: "A mainly cloudy day with bright or sunny intervals. Showers are likely in places, these turning heavy and thundery by the afternoon. Feeling warm in the sunshine. Maximum temperature 22 °C."