The latest storm bound for the UK will bring winds of up to 80mph (128km/h) and a risk to life, forecasters say.
Storm Isha has prompted amber weather warnings for wind for much of England, Wales, Northern Ireland and parts of Scotland from 18:00 GMT. Yellow rain warnings are in place in some areas.
The Met Office said there was a risk to life in coastal areas from large waves and debris being blown inland.
Isha is the ninth named storm to hit the UK since September.
The storm’s strongest winds are expected on Sunday night and into Monday morning, when three amber warnings from the Met Office come into effect.
The first is for parts of Scotland, Northern Ireland and Wales, northern England and south-west England, in force from 18:00 on Sunday to 09:00 on Monday.
Three hours later, a separate amber wind warning begins, covering more of Scotland. It also expires on Monday morning. A third, for south-east England, starts at midnight on Monday, ending at 09:00.
There is a good chance of power cuts, which could affect mobile phone signal in affected areas, while roads and bridges are likely to be shut. Rail and bus services could face delays and cancellations.
Met Office forecaster Ellie Glaisyer highlighted Storm Isha’s potential impact across most of the UK, which she said was “relatively rare”.
She said: “It’s a very widespread storm and it’s going to be affecting everybody. Heavy rain will affect everybody, those strong winds will affect everybody. That’s the main difference to previous storms we have seen.”
East Midlands Railway said it expected “significant disruption” on Sunday and Monday, including delays and alterations to services, while Police Scotland advised people to avoid unnecessary travel.
A spokesperson for Energy Networks Association, which represents Britain’s energy network operators, said on Friday: “An amber warning brings an increased risk of damage to homes and vital infrastructure.
“Energy network operators are preparing to deal with any damage quickly and safely.”
Separate yellow weather warnings – which are less severe than amber – for rain and wind are also scheduled to take effect.
One for northern England began at midnight and lasts until 06:00 on Monday.
Another for Wales starts at 06:00 on Sunday and lasts until the same time the following day.
Details of all weather warnings – including a yellow warning for wind across all four UK nations from 12:00 Sunday until 12:00 Monday – can be found here.
The Met Office has said heavy rain could lead to flooding this week. In England, the Environment Agency has issued eight flood warnings, where flooding is expected, and 52 flood alerts, where flooding is possible, as of Saturday evening.
After days of freezing temperatures and snow in some parts of the UK, higher temperatures are expected by the end of the weekend – but the Met Office has warned it may not feel warmer due to high winds.
Met Office meteorologist Alex Burkill said temperatures were going to be much higher than they have been.
“Quite widely, we could see places reaching highs of 12-13C,” he told the PA news agency, “but we need to factor in the strong winds, the rain, the cloud, and so it is not going to feel quite so warm as this might suggest.”
Storm Isha follows Storm Henk, which hit the UK earlier this month, causing flooding and disruption.
The Met Office names storms when they have the potential to cause disruption or damage. The agency says it is easier for people to follow the progress of a storm on TV, radio or social media if it has a name.