The Met Office has issued a weather warning over a deluge of rain and thunderstorms set to hit the London on Monday afternoon.
The yellow alert warns of heavy rain across much of southern, central and northern England from 3pm on Monday until 9am on Tuesday.
Forecasters say spray and flooding could lead to difficult driving conditions and some road closures.
It also says there is a small chance homes and businesses could be flooded. Where flooding occurs, train and bus services could be disrupted.
BBC Weather has warned that there could be three hours of thundery showers on Monday evening followed by further stormy conditions on Tuesday.
Forecasters have predicted that there could be over 12 hours of rain on Monday into Tuesday.
However the weather is expected to improve markedly later in the week. Dry and sunny conditions are forecast for London on Wednesday, Thursday and Friday with temperatures expected to reach 26C, according to the BBC.
Monday’s heavy rain could lead to over a month of showers according to the legend of St Swithin’s Day.
According to traditional folklore, the weather experienced on St Swithin’s Day (July 15) will continue for the next 40 days – meaning London could be in for a wet rest of the summer if superstition holds true.
The Met Office has also issued a yellow weather warning for rain between 8am and 11.59pm on Monday ahead of forecast downpours of up to 40mm over the course of a few hours.
It spans Wales and parts of western England – including Cardiff, Bangor, Liverpool and Exeter.
The Met Office warned “torrential downpours” are likely, with 15-20mm of rainfall forecast in less than an hour in some places – and 30-40mm within three hours in others.
This may be accompanied by lightning throughout the day, the forecaster added.
