Thunderstorms set to sweep across UK could cause flash flooding

The Met Office has issued a yellow thunderstorm warning across most of England and Wales for the whole of Sunday.

People enjoy the hot weather at Malham Cove, in the Yorkshire Dales National Park (Danny Lawson/PA) (PA Wire)

Thunderstorms set to sweep across the UK this weekend could cause flash flooding, forecasters have warned.

Parts of the UK could face train and bus delays and some communities may be cut off by flooding as warm, humid air causes storms to develop, the Met Office said.

Some areas could be battered with up to 30mm of rainfall in an hour on Sunday and the Met Office has issued a yellow thunderstorm warning across most of England and Wales for the whole day.

The heat is set to continue with temperatures reaching the high 20s.

It comes after NHS chiefs warned the hot weather had contributed to “one of the busiest days on record” in Accident and Emergency departments on Thursday.

Charity Asthma + Lung UK added that the humidity had caused an “unseasonal spike” in asthma-related A&E visits and warned that thunderstorms over the weekend could cause “life-threatening” asthma attacks.

Hosepipe bans have been introduced in Kent and Sussex due to “record levels” of demand for drinking water.

Met Office spokesperson Grahame Madge said: “There are risks of flash flooding associated with these forecast thunderstorms.

“Thunderstorms can unleash very intense rainfall and even hail.

“The impacts from this sudden release of precipitation can create local difficulties especially in urban areas as intense rainfall can lead flood waters to rise on roads, underpasses.

“This far out it isn’t possible to forecast exactly where these systems will form but we are confident that some will experience intense conditions.

“We advise the public to follow the forecast and warnings so they can be prepared should thunderstorms develop at short notice.”