The highest sea levels in 20 years are due tomorrow as fierce storms sweep in from the Atlantic. Swathes of the country are braced for 75mph gales on Monday with up to an inch of rain.
The Environment Agency has issued flood warnings across most of the country and another serious flood warning in the North-east.
Wind and rain today will end the settled weather with temperatures expected to plummet.
Eight inches of snow could settle in the North by Sunday with wintry showers forecast as far south as Wales and the Cotswolds.
Northern temperatures will plunge to –3C (27F) tonight and the South will see lows of –1C.
Windchill will make it feel like –11C. Motorists have been warned to take care on dangerous icy roads.
Chris Burton, of The Weather Network, said: “A much more unsettled period is expected. Cold weather will spread to all areas by Saturday with sleet and snow on high ground.
Heavy rain will fall in all areas, perhaps as snow across northern areas – where eight inches could accumulate on hills
“Heavy rain will fall in all areas, perhaps as snow across northern areas – where eight inches could accumulate on hills.”
The Met Office said winds could hit severe gale force from Sunday. Forecaster Nicky Maxey said: “There’s heavy rain coming. The heaviest will be in the South-west.
“Winds will pick up into Monday with gusts of 70 to 75mph. Tides are also peaking on Saturday and this could be an issue.”
Rivers such as the Wye on the Wales-England border are likely to overflow and coastal areas have been warned of 50ft waves threatening residential areas.
Leon Brown, of The Weather Channel UK, warned it would be a “washout” weekend and bookmaker Coral has been “snowed under” with bets on it snowing.
Spokeswoman Nicola McGeady said: “There’s been a flurry of bets on snow before the week is out.”