The worst storm in five years hit England and Wales on Sunday night, bringing heavy rain, high winds and the threat of flooding and travel chaos.
Winds of more than 80mph could leave a trail of destruction across large parts of the UK, knocking down trees and causing major structural damage and power cuts. The Met Office reported winds of more than 60mph hitting Plymouth in the early hours of Monday.
A 14-year-old boy was feared dead after being swept into the sea while playing in the surf in rough weather conditions.
The unidentified youngster disappeared from West Beach at Newhaven, East Sussex, at about 4.15pm.
Rescue teams, including a coastguard helicopter and a RNLI lifeboat, scoured the area in what were described as "atrocious conditions" with poor visibility. But the Maritime and Coastguard Agency (MCA) said the operation had now become one of search and recovery.
The teenager was playing with friends when the incident occurred. They were not swept off and are safe.
A Sussex police spokesman said: "This is a very distressing incident and everything possible is being done to try to find the boy." A MCA spokeswoman said that rescue teams struggled in difficult conditions. She explained that police were with the boy's family and "they are distraught".
The storm, named after St Jude – the patron saint of lost causes whose feast day is on Monday – will develop over the Atlantic and is expected to hit the south-west late on Sunday, before moving north-east across England and southern Wales.
Eight flights between Ireland and London Heathrow have been cancelled because of the severe weather. Aer Lingus took the step as England and Wales braced itself for storms.
The rough weather has also led a number of rail companies to suspend or cancel their services. Greater Anglia said it would not run any trains before 9am on Monday, after which it would be running a reduced service, but said it anticipated significant disruption through the day.
Southern trains said it would not be running its services – including the Gatwick express – on Monday morning until it was satisfied that it was safe to do so.
South West Trains has advised passengers not to travel on Monday and announced a significantly reduced service, with most of its trains not expected to run until at least 8am. Southeastern trains also indicated that its services may not begin until 9 or 10am on Monday. Transport for London said it would not be running any trains on its overground service before 9am.
David Cameron said he had spoken to the organisations responsible for public safety during the storm. The prime minister wrote on Twitter: "I've just chaired a call with various government departments and agencies to hear about all the plans to ensure people are protected from tonight's storm."