There could be a "danger to life" from heavy rain and flooding across much of Wales until Tuesday, with up to a month's worth falling within 24 hours, forecasters have warned.
An amber warning that "heavy rain is likely to bring some disruption and probable flooding", issued by the Met Office, has been extended in most of South Wales until 11.59pm on Monday.
The warning states "fast flowing or deep floodwater is possible, which could cause a danger to life" in the majority of South Wales.
Yellow rain warnings, meaning disruption is possible, have also been issued in parts of England and Wales from the early hours of Monday to 3am on Tuesday, and until 9pm on Monday for southwest and parts of central Scotland.
The Met Office said: "Whilst the rain may ease for a time during the afternoon across southern Scotland, another pulse of heavy rain is possible here during the evening, with all rain eventually clearing by late Monday."
Monday could be "a significant event for many", and its impact will likely be greater because the ground is already saturated, the Met Office added.
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Forecasters predict 120mm (4.7in) of rain could fall in the highest ground of the area covered by the amber warning in South Wales, while 20mm (0.8in) to 40mm (1.6in) is expected widely and up to 80mm (3.1in) is likely in hilly parts.
The amount of rain projected to fall on Monday has caused landslides in Wales in the past, according to the British Geological Survey.
Around 240mm (9.4in) has already fallen in Wales this month, almost 100mm more than its November average of 162mm (6.4in), according to the Met Office.
England and Wales together have had 143% of the normal rainfall, the agency added.
Senior operational Met Office meteorologist Marco Petagna said "all areas have seen above normal rainfall".
Parts of England and Wales "have seen already well-above normal rainfall and another several inches to come", he added.
Monday could be a "significant event for many" with flooding and landslides possible, he warned.
"Strong south to southwesterly winds will also accompany the heavy rain, with gales possible around coasts and over high ground."
Homes and businesses could be flooded, and there may also be travel disruption and power cuts.
Some communities could be cut off by flooded roads, officials said.
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In an update on Monday morning, Natural Resources Wales (NRW) listed three warnings for expected flooding in parts of Wales. The body has also issued 48 alerts for possible flooding.
Richard Preece, NRW's duty tactical manager, said: "With some rivers already swollen and the ground saturated, we expect to see a number of flood alerts and warnings issued."
The Environment Agency has posted six warnings for expected flooding in England - and 57 alerts for possible flooding.
Scotland's Environment Protection Agency has issued seven flood alerts.
(c) Sky News 2025: UK weather: Danger to life warning for parts of UK as 'month's worth of rain' to fall in 24 hour
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