A yellow warning of thunderstorms is in place throughout today until 11.59pm tonight. The warning is in place across England. There is also a yellow warning of rain in Scotland which is in place until the end of the day. A further warning of thunderstorms has been put in place tomorrow across South East and South West England.
The Met Office warned that the thunderstorms may bring “flooding of homes and businesses”, which could happen “quickly”.
They also warned that “fast flowing or deep floodwater is possible, causing a danger to life”.
The forecaster predicted delays and cancellations to public transport services as a result of flooding and lightning strikes, adding that “power cuts might occur and other services to some homes and businesses could be lost”.
It said that “some communities might become cut off if roads flood”.
The Met Office warned that up to 50mm of rain could fall in under three hours in some places, while other places will see hail.
It said: “Thunderstorms and areas of heavy rain will develop quite widely across much of England and Wales.
“The extent of these thunderstorms will be more widespread than on Monday, though some spots will still miss storms and remain dry.
“20-30 mm of rain is possible within an hour, but where areas of thundery rain become slow-moving, some places could see 50 mm in less than three hours.
“There is a chance that higher totals could occur in a few spots over the course of the day.
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“This rain will start to become lighter and patchier during Tuesday morning before finally easing later on Tuesday.”
The flood risk is exacerbated by the dry ground, caused by hot weather and a lack of rainfall in recent weeks, as falling rain is less able to soak into the soil.
Met Office forecaster Dan Stroud explained: “Rain from really intense downpours will be unable to soak into the baked ground quickly.”
He added: “It’s very difficult for the water to actually get in because it has to force the air out of the soil.
“So dry ground gets very quickly overwhelmed, and we then get surface run-off.”
London Mayor Sadiq Khan has warned people in the capital to prepare for flash flooding this week as a result of the severe weather.
He said London could see a “huge amount of rain in a short period of time”, saying he has written to “tens of thousands of Londoners who live in homes that could be affected by flash flooding.”
The Mayor advised Londoners to contact flood support agency Floodline and take action to “minimise the consequences”.