The UK may be hit with “blood rain” this week as heavy thunderstorms mix with a dust cloud from the Sahara, the Met Office has said.
Parts of the country could have red or orange rain over the coming days as lightning, strong winds and hail move in.
The Met Office said the phenomenon occurs when relatively high concentrations of red coloured dust or particles get mixed with rain, which give it a red appearance as it falls.
A yellow thunderstorm warning has also been issued from this evening into the early hours of Thursday in the southeast, including London.
People should expect travel disruption from potential flooding, the Met Office warned.
Check the forecast for where you are
Britons basked in the country’s hottest day of the year yesterday, after temperatures in the southeast peaked at 27.5C (81.5F).
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Richard Miles, of the Met Office, said: “There are some dust concentrations in the atmosphere above the UK at present which might well be washed out in the rain tonight, but it’s likely to be relatively small amounts on the whole.
“There’s a warning out for thunderstorms for the south-eastern third of England tonight, and a squally cold front will bring wind and sometimes heavy rain to Northern Ireland and northwest Scotland this evening.
“Away from these features it will be mostly fine and dry today and tomorrow, temperatures up to 23-24C in London and the South East, high teens or low 20s elsewhere.”
Risk of lightning and power cuts
The dust cloud is likely to come from the Sahara, according to the Met Office.
“Each year on several occasions the UK will see rain falling with some amount of dust mixed into it,” it said.
“This usually comes from the Sahara before mixing in clouds and falling out.”
The thunderstorms may cause spray and sudden flooding, leading to difficult driving conditions and some road closures.
There may also be delays or cancellations to train and bus services, flooding to homes and businesses, power cuts and damage due to lightning strikes.
Heavy rain is expected to fall during Wednesday and Thursday in parts of Scotland and Northern Ireland, while showers will also hit areas in Wales and central and southwest England.