A fresh amber weather warning for heavy rain has been issued by the Met Office - with much of the UK already on alert for high winds and showers.
Northern Ireland, Scotland and the UK's west coast and the Midlands have yellow warnings for wind on Sunday - meaning the possibility of transport delays and short-term power cuts.
There are also rain warnings in place for several parts of western UK.
The new amber warning has been issued for rain in south and central Wales and is in force from 3pm on Sunday to 6am on Monday.
An amber warning means danger to life from floodwater, homes and businesses are likely to be flooded, and there is a chance some communities will be cut off.
Winds across the west of the UK will increase throughout the morning with gusts up to 70mph in exposed areas, the Met Office said.
Zoe Hutin, a meteorologist at the forecaster, said Sunday is expected to be the "worst day" before conditions improve.
"The wind warning itself for the mainland UK ends at 6pm, but we can expect to continue to see quite blustery conditions even into the evening as the mainland rain itself pushes through."
She added: "By the time people get up on Monday, we'll still have some of the residual rain from that front in the far south-east of the country, and quite cloudy across England as well.
"But actually elsewhere, it could be a decent start."
The Met Office's yellow weather warnings for much of England and Scotland came into force at 6am and are expected to run until 6pm on Sunday.
A separate yellow warning for Northern Ireland came into force at 3am and runs until 3pm.
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People who have noticed some slightly higher temperatures the last couple of days may be dismayed at the latest predictions.
"Through the week, those temperatures are trending back down," Ms Hutin said.
"And so it will be getting cooler each day, but they will actually just be recovering to around average for the time of year. So it won't be cold.
"It will just be returning back to where we would expect to be for this time of February."
(c) Sky News 2025: Fresh amber warning for rain as Met Office issues alerts for much of UK
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