The second red "danger to life" weather alert in a week is in place in eastern parts of Scotland, with torrential rain and high winds forecast across the UK.
Forecasters say another 70-100mm (4ins) of rain could fall on Saturday in parts of Angus and Aberdeenshire already hit by severe flooding.
Three severe flood warnings have also been issued in Derbyshire, which mean there is a significant risk to life.
Three people have died since Thursday, when Storm Babet first took hold.
The flood warnings for England are in place at Derby City Water Treatment Works, Little Chester, Eastgate and Cattle Market, and Racecourse Park at Chaddesden.
People across Scotland remain in temporary accommodation due to floods.
The red weather warning will run until 18:00. The Met Office previously had the warning in place until midnight.
Amber and yellow warnings for rain and wind cover much of eastern Scotland, while a yellow wind warning is in place for north-east England.
Train services in Scotland "will be badly disrupted" on Saturday and lines elsewhere in the UK have been flooded overnight, Network Rail said.
It warned some routes in England would also be impacted, including "several" lines in north-east England; the Midland Main Line from Sheffield to London; "widespread" disruption across the Midlands; Greater Anglia services due to flooding in the Stowmarket area.
The Environment Agency is monitoring Ladybower reservoir in Derbyshire, which is close to capacity after heavy rainfall. An overspill could cause flooding along the River Derwent.
Clive Stanbrook, area manager at Derbyshire Fire & Rescue Service, told OceanNewsUK - including 20 care home residents - had to be rescued on Friday.
Storm Babet: The story so far
- Three people have died, including a man in his 60s who was caught in fast-flowing flood water in the town of Cleobury Mortimer in Shropshire on Friday
- A 56-year-old man died after his van hit a tree near Forfar, and a 67-year-old woman was killed after being swept into the Water of Lee
- Dozens of people have taken shelter in emergency accommodation - many in Angus and Aberdeenshire as well as 50 in the rural village of Debenham, Suffolk
- In Scotland, roads and bridges collapsed and dozens of households had to be rescued in Angus, where flood defences were overwhelmed in the early hours - river levels rose 4.4m (14ft) higher than normal and continued to increase on Friday
- Almost 13,000 households were without power late on Friday night - 10,000 across England and 2,800 in Scotland
- Police forces have advised against travel in the red alert area
- Earlier on Friday Leeds Bradford Airport shut after a plane skid off the runway in the storm. Bosses hope to open the airport at 11:00 BST on Saturday.
Angus Council - which was hit by the first red alert on Thursday - said it was prepared to call on the military for assistance if the situation in the region worsened significantly.
Brechin in Angus has been among the worst hit areas, with 60 households having to be rescued after they chose to remain in their homes despite an evacuation warning for the entire town.
Motorists across Scotland have been warned to exercise caution by police amid an ongoing search for a driver who was reported to be trapped in a vehicle near Marykirk in Aberdeenshire in the early hours of Friday.
What is a red weather warning?
Red is the most severe of the Met Office's three coloured weather warnings.
It means that dangerous weather is expected and, if you have not already done so, you should take action now to keep yourself and others safe from the impact of the severe weather.
It is very likely that there will be a risk to life, with substantial disruption to travel, energy supplies and possibly widespread damage to property and infrastructure.
You should avoid travelling, where possible, and follow the advice of the emergency services and local authorities.
