Britons have been warned by forecasters as the country braces to be battered by a month's worth a rain in just 24 hours.
The Met Office have issued an amber alert, signalling a possible “danger to life” for parts of Wales with flooding predicted.
The alert is effective from midnight until 11.59pm on Monday, December 1 in South Wales, where forecasters anticipate up to 120mm of precipitation on elevated terrain.
Lower-lying areas are expected to receive between 20mm and 40mm, while hillside locations could see accumulations reaching 80mm.
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The warning specifically highlights the risk of rapid water flow and deep flooding that poses a direct threat to life.
Officials anticipate widespread flooding could result in property damage to residences and commercial premises, while transport networks face likely cancellations.
Power supplies may be interrupted and certain communities risk complete isolation due to impassable roads.
The Met Office's amber alert also cautions about powerful southerly to south-westerly winds accompanying the deluge, with coastal areas and elevated regions potentially experiencing gale-force conditions.
A month's rainfall is expected to fall in just 24 hours over South Wales
|WXCHARTS
Natural Resources Wales has issued urgent guidance for residents to begin flood preparations immediately.
Richard Preece, the organisation's duty tactical manager, stated: "We are asking people to be alert for potential flooding, with heavy rain predicted overnight on Sunday into Monday morning, especially in parts of South Wales."
“With some rivers already swollen and the ground saturated, we expect to see a number of flood alerts and warnings issued.
Mr Preece emphasised: "We're urging people to be vigilant and to make preparations for potential flooding now."
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The Met Office have issued an amber alert, signalling a possible 'danger to life', for parts of Wales
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Residents have been advised to assemble emergency kits containing essential documents and medications, relocate vehicles to elevated areas, and transfer valuable items to upper floors.
Officials have stressed the public must avoid riverbanks and refrain from traversing floodwater.
"We also want to remind people to keep away from swollen riverbanks and not to drive or walk through flood waters as you don't know what lies beneath,” Mr Peerce said.
The Met Office's Chief Forecaster Rebekah Hicks warned less severe but still notable yellow warnings would also be in place across the rest of Wales, western England and southwest Scotland.
She explained “disruption also possible in these areas through the day”.
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