Severe flood warnings have been issued in coastal areas as "exceptional" weather is forecast for parts of England and Wales.
The Environment Agency has put 19 of the most serious warnings in place, most of which are in south-west England, with parts of Gloucestershire and north Wales also set to be hit by storms.
Heavy rain and winds gusting up to 60mph are due to hit western areas in the morning, prompting fears of disruption.
Environment Secretary Owen Paterson, who chaired a meeting of the Government's Cobra emergencies committee, said "exceptional" weather was expected and warned energy network companies to be prepared, following complaints it took too long to restore electricity to the thousands of homes left without power in the wake of severe weather over Christmas.
As well as the severe warnings, issued when there is a threat to life or property, there are 186 flood warnings and 234 flood alerts across the country. In London, the Thames Barrier was closed to protect people and property along the river.
The Environment Agency said strong winds, combining with high tides and large waves, are set to hit coastal communities.
In a statement on their website, the agency said: " The flood risk will extend along the UK coastline from north-west England, through Wales and south-west and southern England. Areas particularly at risk include the Isles of Scilly, the north and south coasts of Devon and Cornwall, Dorset and the coastline of Wales."
The storms have already claimed at least two lives. T he body of a 27-year-old man, from Surrey was found on Porthleven Sands beach in Cornwall this morning. He had been swept out to sea on New Year's Eve night having gone for a paddle with friends at nearby Loe Bar.
In a second tragedy on Tuesday, a woman died after being swept out to sea at the popular beauty spot Croyde Bay in north Devon. T he woman, who was believed to be on holiday with her family, was rescued from the sea and airlifted to hospital before being confirmed dead by doctors.
Elsewhere, in Dorset a search was carried out for a man who is believed to have fallen into the River Stour, near Iford Bridge in Christchurch yesterday.
There was a brief respite from the most severe weather today, but heavy rain is expected in western areas of England, Wales, Scotland and Northern Ireland tomorrow as a low pressure system moves in from the Atlantic.
Pete Fox, head of strategy at the Environment Agency, urged people to be vigilant near the coast.
He said: " Coastal paths and promenades could be highly dangerous as there is an increased risk of being swept out to sea. People are warned to stay away from the shoreline."
Bosses at energy network companies are due to face questions from MPs when Parliament resumes next week.
They were criticised over the length of time it took to restore power to homes affected by storms over Christmas, while Prime Minister David Cameron was confronted by one angry resident in Yalding, Kent, during a visit to see the flood damage last week.
More than 150,000 homes were cut off after strong winds, torrential rain and flooding caused damage to power networks but today Mr Paterson said he expected the power companies to do their best to prepare for the latest storm.
Speaking on Sky News following the Cobra meeting in London, he said: " We are looking to have a combination of exceptional rain, wind and a surge in sea and high tides and so there are nearly 50 warnings put out around the whole of the west coast and south coast.
"We had a range of ministers from right across government attending the meeting, who will be working very closely with local councils, power companies, utility and transport companies, making sure that all of those organisations are absolutely prepared for the bad weather that is coming."
The AA, which has attended 1,500 call-outs from those stranded due to floods since December 23, said some drivers were failing to heed warnings.
Darron Burness, head of the AA's flood rescue team, said: "Our patrols have seen it all in that time - including people ignoring road closure signs, blindly following their sat-nav or other drivers into deep water and 4x4 drivers naively thinking their car has amphibious qualities - and time and again they hear the same excuses that the driver didn't think the floods were very deep or that their car could deal with it."
In Scotland forecasters have warned of potential coastal flooding as more rain and high winds are set to hit the country.
Heavy rain and gusts of up to 60mph could sweep across the country tomorrow, bringing further disruption after days of wet weather.
High tides and a storm surge have increased the risk of flooding in the Firth of Clyde, according to the Scottish Environment Protection Agency (Sepa).
A tidal surge is expected around lunchtime on Friday, particularly around the Firth of Clyde, Solway Firth and Ayrshire, the Scottish Government said.
Sepa has issued a flood alert for west central Scotland, warning that high water during early afternoon on Friday will be "exceptionally high" with large waves likely.
It has also issued eight flood alerts and 17 flood warnings for other parts of Scotland.
The Met Office has issued yellow "be aware" warnings of heavy rains and strong winds for the Highlands and Western Isles, Strathclyde, Central, Tayside, Fife, Southwest Scotland and Lothian and Borders.