Thunderstorms are set to bring a sudden halt to the short sunny spell in southern parts of England and Wales, prompting the Met Office to issue two yellow weather warnings.

Heavy rain is forecast, with storms expected to hit the south west and Wales from 8pm on Wednesday through to 8am on Thursday, while south east England is due to be affected from 11pm to 6am.

The warnings come after the UK experienced its sixth wettest April since records began, according to provisional data.

The Met Office advised the storms might cause travel disruption and some flooding, leading to “difficult driving conditions and some road closures”.

There is also a chance of delays and some cancellations to train and bus services, along with a small possibility of power cuts.

Nicola Maxey, spokeswoman for the Met Office, said that while southern parts will experience heavy rain, northern parts should stay dry and warm.

She said: “We have a weather front moving north, coming up across the south west, and then later in the evening we have some air pushing in from the near continent, so two discrete weather systems.

“So some potentially heavier rain more widespread with the threat of thunderstorms and then the air from the near continent into the south east and up across London and further north again bringing the risk of thunderstorms, perhaps more isolated thunderstorms.

“Those bring the risk of lightning, hail, thunder, obviously, and isolated heavy downpours.”

She added: “Elsewhere, there is certainly drier weather in the north and it is trending warmer.”

Last month was the sixth wettest April for the UK since records began in 1836, with an average of 111.4mm rain across the country, according to provisional Met Office figures.

2012 holds the record for the UK’s wettest ever April, with 128.2mm rain during the month.

Scotland saw its fourth wettest April this year, with 148.9mm of rain – the highest for the month since 1947.

Some areas of Scotland saw more than double their average rainfall, including Edinburgh which experienced its second wettest April on record.

The average mean temperature for the UK in April was close to normal, with warm weather in the first half of the month offset by cooler conditions in the second half.