Half a month’s rainfall could hit the UK in the next 24 hours, the Met Office said on Sunday, issuing weather warnings across the country.
Yellow weather warnings for rain and thunderstorms were in place in Northern Ireland, Scotland and the north and south-west of England until 10pm on Sunday, with more warnings coming into force in other areas on Monday.
Eastern parts of Northern Ireland were to be covered by a 24-hour weather warning, from 6pm on Sunday until 6pm on Monday, with heavy rain expected to cause some disruption and possibly flooding.
Simon Partridge, a forecaster at the Met Office, said: “It looks like Northern Ireland is the place where we could see the most rainfall and certainly the most impactful rainfall. They could see 50 to 75mm of rain within 12 to 18 hours.”
Northern Ireland records an average of 89mm of rain in July, meaning more than half a month’s rainfall could hit it in less than a day.
Flooding is also possible, the Met Office said, and parts of England and Scotland may also have 20-40mm of rain in just two hours on Monday.
Extreme rainfall is more common and more intense because of human-caused climate breakdown across most of the world, particularly in Europe. This is because warmer air can hold more water vapour.
From 3am until 9pm on Monday, the south and east of England are covered by a yellow thunderstorm warning.
By 11am the same warning will be in place for the Midlands, northern England and Scotland.
More than 10 flood alerts remain active in Scotland, and where there is flooding or lightning the Met Office has warned trains and bus services may be delayed or cancelled.
There is also a small chance of power cuts and of fast-flowing or deep floodwater causing danger to life.
The wet weather comes after a third heatwave of the year that left four areas of England in drought and led to several hosepipe bans being declared.
Dry ground makes flooding more likely, as it is unable to absorb as much water.
