Many parts of Britain could see up to 3ins of rain and strong winds as 22 hours of downpours trigger fears of flooding.
Some localised flooding to homes and businesses could occur and members of the public are warned that journey times could be longer.
In a statement, the Met Office said: “Rain, accompanied with strengthening winds, will move north and eastwards across the area early on Tuesday, becoming slow-moving over parts of northeast England and, later, also eastern England.
“15-30 mm of rain is expected to fall quite widely. Over eastern and northeastern England, 40-50 mm of rain is likely to fall in some parts with 50-75 mm also possible in a few spots.”
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Across Wales, southern Scotland, central and northern England will see cloud and rain, while other parts of Britain will be mostly bright with sunny spells but a few showers in the west.
Near the coast in the south and east will be particularly windy.
Forecasters have predicted this week will be one “of two halves”, with Monday and Tuesday seeing the country battered with torrential rain and 60mph winds.
But from Thursday the mercury is thankfully expected to begin climbing, with the potential to reach 21C in some places on Thursday and Friday.
A meterologist at AccuWeather, Tyler Ros, told Express.co.uk that Tuesday will see Hurricane Sam, which is churning in the Atlantic, become a tropical rainstorm just southeast of Canada.
UK weather forecast
Cloud and rain, heavy at times across Wales, southern Scotland, central and northern England slowly moving east.
Otherwise bright with sunny spells but also a few showers in the west. Windy, especially near coast in south and east.
Rain in the east slowly clearing. Otherwise clear spells and a few showers in the west and southwest. Breezy with strong winds in east.
Any lingering rain in far east soon clearing.
Dry with some sunshine, but cloud increasing in west with further rain sweeping northeastwards across Northern Ireland reaching northwest Britain later.
Outlook for Thursday to Saturday:
Rain, heavy and persistent at times, will affect parts of Scotland and Northern Ireland.
Dry elsewhere with variable cloud, sunny spells and overnight fog patches. Warmer than of late.