The break-up of the big chill in the US will drop more rain onto already swollen rivers and saturated ground.
More heavy rain and wind is on on the way at the end of the week as the fallout from the the blast of freezing polar air battering the US hits the UK.
A weather system forming part of the record-breaking polar vortex that has affected half of America is heading across the Atlantic, warming as it comes.
The Met Office had already extended its severe weather alert until Thursday morning, warning of more floods as saturated ground and swollen rivers in the south of England and Wales may not cope with more rain.
But further heavy falls will be swept in when the US weather system reaches the UK on Friday.
Sky’s US Correspondent Dominic Waghorn said the worst of the big freeze in America should now be over, with temperatures set to rise.
“That’s good news for Americans but not necessarily for the rest of us,” he said.
“Meteorologists warn that when a polar vortex breaks up it scatters its forces literally to the four winds, meaning that the extreme weather experienced here this week could be flung as far afield as Europe.”
The Met Office has its lowest warning in place, forecasting “periods of heavy rain” in the south west of England and Wales on Wednesday into Thursday.
Between 30-40mm of rain is expected to fall in the wettest spots.
A Met Office spokesman said: “The public should be aware of the potential for further flooding, especially in the areas which have been affected recently.
“Given current sensitive hydrological conditions, there is a risk of further surface water flooding in Wales, and both river and surface water flooding in Cornwall, Devon and Somerset.”
There are no longer any severe flood warnings in force from the Environment Agency, but there are 114 flood warnings in place across the country.
A further 195 low-level flood alerts are also in force.
Paul Mustow, flood risk manager at the EA, said: “The risk of flooding continues this week, with communities in the South West and South East urged to stay safe and sign up to free flood warnings.”
Seven people have died and more than 1,700 homes and businesses have been flooded in England since the beginning of the Christmas period, with around 550 properties flooded since the new year.
Some 140 properties have been flooded in Wales.
Flood defences protected 220,000 properties over the Christmas period and another 800,000 were protected during the coastal flooding in early December.