Heavy rain is forecast to fall this evening, feeding already swollen rivers in Cumbria, where flooding has hit some areas three times already this month.
Flood alerts have been issued across a swathe of the country, with around 30 flood warnings, stretching from Wales to Scotland.
But the north of England is expected to bear the brunt again, as Storm Eva rolls in.
A Defra spokeswoman said: "As a result of the weather forecast, there will be a ministerial Cobr on Christmas Day to review the latest situation and receive further updates."
Another deluge of up to six inches of rain is expected in Cumbria, which has already suffered the wettest December since records began in 1910.
A multi-agency Strategic Coordination Group has been set up to combat the expected flooding.
Armed forces personnel have been called in and 700 Environment Agency (EA) staff are on stand-by to bolster flood defences as more sandbags and water pumps are rushed to Cumbria.
Flood defence gates have been closed in Carlisle, Keswick and Cockermouth and the EA has transported over two kilometres of temporary flood barriers and more than 20 extra pumps to the north of England.
Teams of workers from the agency have also been out checking and maintaining flood defences, clearing blockages in watercourses and monitoring water levels.
The Met Office has issued an amber alert for the county, highlighting the increased likelihood of "medium impacts" from the rain, meaning some flooding of homes, businesses and transport links is possible.
Rain will spread across Wales and northern England through the course of Christmas Day, reaching southern parts of Scotland during the early hours of Boxing Day, with prolonged spells forecast for south Cumbria.
The latest deluge will come as towns and villages across the county are still clearing up the aftermath of Storm Desmond earlier this month, which left hundreds of homes and businesses under water.
Around 40 roads and bridges remain damaged and closed, along with hundreds of homes left uninhabitable.
Cluanie Inn in Inverness, Scotland, was where the most rain fell overnight, with 0.78ins (19.8mm) recorded between 5pm and 5am, a Met Office spokesman said.
Elsewhere, the EA said that for the next three days along the River Severn in Shropshire, Telford & Wrekin and Worcestershire, and the River Ouse in York, there is a possibility of sections of roads being flooded, travel disruption and delays due to temporary flood defences being deployed.
High tides are also expected, bringing with them the potential for large waves and spray along parts of the south and west coast of England.
Sir James Bevan, chief executive of the Environment Agency, said that after the latest run of bad weather the agency will talk to the communities affected to look at how they can be better protected in the future.
More information and help is available at www.gov.uk/check-if-youre-at-risk-of-flooding or follow @EnvAgency and #floodaware on Twitter for the latest flood updates.
Traffic and travel information is available at www.cumbria.police.uk/traffic-link-map and a helpline has been opened on 0345 988 1188.