Whilst the wind will generally be weaker than yesterday, torrential rain could cause flooding, power cuts and isolate communities.
Met Office meteorologist Aidan McGivern said: “It’s the rain in particular which is of concern, especially in South Wales where we start off the weekend with an amber warning in place.
“The rainfall has been building up through Friday and it continues through Saturday.”
In some areas it could “cause significant impacts” including “flooding, communities to be cut-off and power cuts”.
The amber weather warning affecting south Wales means there is a likelihood of “severe of extremely bad weather” which could pose a “potential risk to life and property”.
Saturday will start with rain across Wales, northern England and southern Scotland.
Mr McGivern expects it to be: “Much drier further south east which will have a bright start to the day.
“Remarkably mild at 18 or 19 degrees and clearer also in the far north-west of Scotland.”
During the morning, rain will push into Northern Ireland and central Scotland.
However, central and eastern parts of England should remain dry, and here temperatures could reach 25 or 26 degrees in the afternoon.
Mr McGivern explained: “It will be another windy day, just not as windy as Friday.
“It’s Irish Sea coasts especially that will see some keen gusts throughout the day.
“The wet weather builds up across western hills, in particular south-west Scotland, north-west England as well as Wales and the South West.”
These areas could see “three or more inches of rainfall”.
However, by the end of the day most of the wet weather will have been pushed eastwards away from the UK though heavy rain should still be expected in northern Scotland.
Sunday is expected to be a lot dryer and brighter.
Mr McGivern predicted: “The north-west and the south-east getting off to a wet start on Sunday.
“Clearer elsewhere and a lot of dry weather.
“Finally sunshine reappears across western parts of England.”