The third named storm of the season is expected to bring very strong winds of 50mph to 60mph across the whole of the country from Sunday morning.
Some parts will see gusts of more than 80mph, increasing the risks of injuries from flying debris, damage to buildings and large waves battering the coast.
Heavy rain could also cause flooding to homes and businesses in parts of England and Wales, while rail, air and sea passengers have been warned to expect severe disruption this weekend as the storm hits the UK.
The Met Office has issued a series of weather warnings from Saturday night until midday Tuesday to ensure the public are prepared for the disruption to transport and other services.
“It is going to be more significant than the other two storms we have seen this season,” said Met Office meteorologist Simon Partridge.
“In terms of widespread effect, the last one it is on a par with was in 2013. Everybody will feel some effects from it.
“It is heavy rain as well as the winds, which will be quite widely 50 to 60mph. That’s the reason for naming it.”
One weather warning was upgraded from yellow to amber for the southeast coast of England between 9am and 9pm on Sunday. It advises of an increased risk of injuries, building damage, road closures and power cuts.
Storm Ciara is the first of a series of low-pressure systems being steered towards the UK by an “extremely strong jet stream”, said Met Office chief meteorologist Frank Saunders.
“Our confidence in the forecast means we have been able to issue severe weather warnings well in advance, giving people time to prepare for potential impacts of the storm,” he added.
Network Rail will impose a blanket speed restriction of 50mph on many lines on Sunday due to concerns that debris could be blown on to train tracks by high winds.
“High winds have the potential to damage overhead lines and tracks, for example through debris or lineside trees falling on to the railway,” the infrastructure manager said.
“To keep passengers safe, reduced services and speed restrictions are likely to be in place across large parts of the rail network on Sunday.”
The infrastructure provider has also warned that disruption could continue into Monday morning as scheduled repairs may be delayed.
Irish Sea and English Channel ferry services are also expected to be affected by the storm, although the scale of the disruption is not yet known.
Strong winds will first be felt in Scotland and Northern Ireland on Saturday, before spreading across the whole of the UK on Sunday.
Warnings for wind and snow – bringing the chance of air and rail cancellations, stranding of vehicles and power cuts – are in place for Scotland and Northern Ireland until Tuesday.
The Environment Agency warned on Friday night of the risk of flooding for the west and south coasts of England and Wales.
The 2013 winter storms, which were themselves said to be the worst since 1987, caused flooding along the east coast of England, with more than 1,300 properties affected.