Britons could face travel chaos on Saturday as heavy rain causes disruption on the roads amid a strike by train drivers.
The Met Office has issued yellow weather warnings for parts of Wales, England and Scotland, with downpours causing flooding on roads and making journey times longer.
Flooding of homes and businesses is also possible.
The weather warnings come as train drivers in 11 companies, belonging to the Aslef union, will strike in a long-running dispute over pay.
Rain, at times heavy, is set to hit parts of south Wales and south-west England between 2pm on Saturday and 3am on Sunday.
Cardiff, Swansea and Carmarthen in Wales, and Plymouth, Southampton and St Austell in England are among areas that could be affected.
The Met Office said: “Rain is expected to develop across south Wales and south-west England during Saturday afternoon, moving slowly east to clear most areas early on Sunday morning.
“Although the most persistent rain is expected over hills, periods of heavy rain are expected almost anywhere. 15-25 mm is expected quite widely, with some places seeing 40-60 mm of rain, particularly over hills in south Wales and south-west England.
“Strong winds will accompany the rain, with gusts of 45-55 mph over hills and around coasts.”
From noon to midnight on Saturday, parts of Scotland including Perth and Sterling could also get heavy rain.
The Met Office has warned that “heavy rain may lead to some flooding and disruption to travel” during this period.
It added: “Rain will turn persistent and heavy at times across the warning area through Saturday afternoon and evening.
“Accumulations of 20 to 30 mm are expected with 45 mm possible on high ground.
“Given existing saturated ground there is a risk of some localised flooding.”
Beyond that, the Met Office weather outlook for Sunday to Tuesday states: “Rain across England and Wales will slowly clear Sunday, with blustery showers following to the north.
“Showers in the north die out Monday, with many areas dry Tuesday.
Passengers have been urged to plan ahead and check before they travel throughout the whole weekend due to the planned strike.
Trains that are running will start later on Saturday morning and finish much earlier than usual, with services typically running between 7.30am and 6.30pm on the day of the strike.
Rod Dennis, a spokesman for RAC, said: “Further rail strikes will leave people with a pretty stark choice this weekend – either take to the road to complete their trips, or cancel their plans altogether.
“We’d expect many people to opt for the former so, given the challenging weather conditions and higher traffic volumes, it’s vital drivers are on their guard.
“Our advice is to motorists is to slow down to the conditions, ensure headlights (not fog lights) are switched on, and build in sufficient breaks for anyone travelling longer distances.”