Storm Callum is starting to make itself felt ahead of the arrival of torrential downpours and winds of up to 70mph over parts of the UK on Friday.
Heavy rainfall could present a risk to life, the Met Office said, as it issued a 36-hour amber warning for Wales where nearly a month’s rain could fall over 48 hours.
The forecast deluge poses a risk of communities being cut off by flooding, while high winds are expected to cause disruption across western areas of the UK.
The Met Office has issued a series of weather warnings stretching from the north-west coast of Scotland to Land’s End, including Northern Ireland, while a number of flood warnings and alerts are in force across south-west England and south Wales.
Winds were starting to pick up late on Thursday, with 48mph gusts recorded on the Isles of Scilly.
“We are also starting to see the rain push in to parts of south-west England and part of the Republic of Ireland,” Met Office meteorologist Alex Burkhill said.
“We’ve got a wind warning which covers all the western side of the UK from 3am. That in itself is likely to bring disruption to roads and there is likely to be some bridge closures and power outages.
“We also have yellow and amber warnings of between 50mm and 150mm of rain for Wales. That’s quite a substantial amount of rain to come and could bring flooding.”
The amber warning remains in place until 6pm on Saturday, while the broader yellow rain and wind warnings that include parts of north-west and south-west England, western Scotland and Northern Ireland will remain in place until midnight on Friday.
Rainfall totals could reach as high as 150mm over the Brecon Beacons, nearly as high as the monthly average of 170mm for Wales.
Meanwhile winds of 50 to 60mph are expected widely in warning area, with gusts expected to peak at 70mph in the most exposed parts.
The high winds, combined with heavy rain, could see leaves and twigs blocking drains, making flooding more likely, Mr Burkhill said.
Windsor, the scene of Friday’s royal wedding, looks set to escape the worst of the storm.
The south-east is expected to be blustery but stay “quite dry”, with temperatures possibly reaching up to 24C (75F).