Fast-flowing flooding could pose a “danger to life” as more than a month’s worth of rain soaks parts of England in less than six hours, forecasters have warned.
The Met Office has issued an amber weather warning for London and the Southeast, where “intense” deluges and thunderstorms are expected on Monday evening.
Up to 60mm of rain is forecast to fall over four to six hours in some areas of the southern England, which has an average June rainfall of 51mm.
A yellow warning for disruption caused by “heavy prolonged rainfall” is in place for the whole of the day across the Southeast, London, the Midlands and parts of Yorkshire.
Forecasters warned the downpours could cause flooding, train and bus delays, and difficult driving conditions.
The amber warning has been issued for London and the surrounding areas, stretching across Hertfordshire, Essex and the southeast coast, from 3pm until 11pm on Monday.
It warns homes and businesses are “likely to be flooded” and “fast-flowing floodwater is possible, causing danger to life”. Travel disruption and power cuts are likely, forecasters said.
“We’re looking at some very heavy showers, very heavy rain – the sort of rain the drains don’t cope with very well so you get surface water flooding very quickly," Met Office spokeswoman Nicola Maxey told The Independent: “It’s that sort of really heavy downpour that has impacts, especially on built-up areas.”
As the rain swept in on Sunday night, the heaviest downpours were in the Kent village of Sellindge, where 15mm fell in 12 hours.
But the Met Office warned the worst was still to come.
Forecaster Steven Keates said: “Probably later this afternoon into this evening and tonight we could see some of the heaviest rain. It is going to be more the persistence of the rain in some places and the intensity for others. Eastern and southern England in particular are likely to be seeing long and persistent bad weather.”
The Environment Agency has issued one flood alert on the River Ravensbourne in London, covering the boroughs of Lewisham, Bromley, Greenwich and Croydon.
It said there was a risk of flooding for low-lying land, gardens and roads that are close to the river between 7am and 6pm.
The agency added: “We are actively monitoring the situation and are prepared to respond if required. Please avoid using low-lying footpaths near local watercourses and plan driving routes to avoid low-lying roads near rivers, which may be flooded.”
Yellow warnings have been issued for much of central and northeast England as the rain sweeps north from Tuesday to Thursday.
The band of rain will also move slightly west before settling, with Northern Ireland and Scotland expected to spared the worst of the weather.
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