Matt Taylor has more on what we can expect from Monday's storm and the areas most likely to be affected by strong winds and heavy rain.
Commuters are being warned of travel disruption on Monday as a storm bringing severe gale-force winds starts moving across England and Wales.
Train companies have cancelled early-morning services, and flights into London have been reduced.
Gusts of up to 80mph (130km/h) are predicted as the weather hits the South West then moves north and eastwards and there are fears of flooding and damage.
The prime minister has chaired talks about plans to protect the public.
In a conference call, joined by staff from organisations including the Met Office and the environment and highways agencies, David Cameron heard the storm could have a "widespread impact", his spokesman said.
But he was told there were plans in place to minimise the effect on public services such as schools, the NHS, transport and power supplies.
In other developments:
- South West Trains passengers have been advised not to travel on Monday with most services not running until at least 08:00 GMT to allow Network Rail to check lines. A reduced timetable will be in operation with journey times extended as some trains are limited to speeds of 50mph
- Airports including Heathrow and Gatwick are warning of possible disruption to flights and advising passengers to check with airlinesbefore starting journeys
- Airlines operating in and out of Heathrow have been instructed to reduce their schedules by between 5% and 20% between the hours of 06:00 GMT and 22:30 GMT, leading to about 60 flight cancellations. This does not apply to long-haul flights
- Eurostar says it will not be running trains on Monday until 07:00 GMT, with early services from London and Brussels subject to delays of at least an hour and all morning departures operating with speed restrictions
- The Environment Agency issued three flood warnings for West Bay Harbour, Lyme Regis Harbour and Chiswell in Dorset for the early hours of Monday morning due to the winds, large waves and strong swell expected
- The Highways Agency is advising motorists to check the weather forecast and road conditions before they travel and to delay journeys if the weather becomes severe
- Several bridges including the M48 Severn Crossing and A249 Sheppey Crossing in Kent are closed. There also are plans to shut the M4 Severn bridge and the Queen Elizabeth II bridge on the M25 in the early hours of Monday, with traffic on the later being directed through the tunnel part of the crossing
- East Sussex County Council says refuse collections have been suspended on Monday because of the safety risk posed by the winds
- The windy conditions are hampering the search for a 14-year-old boy swept into the sea in East Sussex
A kite surfer braved the waves crashing into Newquay, Cornwall
Rail passengers have been advised services on Monday will be disrupted
Four-year-old Will Brewer played in the foam washed ashore in Brighton as high winds picked up
Waves beat the shore at Porthleven in Cornwall. HM Coastguard has warned people to take extra care on cliffs ahead of what is forecast to be a "major Atlantic storm"
These include First Capital Connect and C2C - which have also advised against travel on Monday - and says services are unlikely to begin until 09:00 GMT. Greater Anglia, Southern and Gatwick Express services all say they will not run services on Monday until it is declared safe to do so.
London Overground also said it will not run a service on Monday before 09:00 GMT, while First Great Western has warned of extended travelling times and Southeastern says it is likely to start running services later in the morning.
Several ferry companies have also cancelled services, including some English Channel and Irish Sea crossings.
The Met Office said 20-40mm (0.80-1.6 ins) of rain might fall within six to nine hours in the wettest areas.
Just before 18:00, the Met Office said in atweet: "Rain associated with tonight's storm now moving across southern counties of England & Wales."
The Met Office said the predicted storm - named St Jude after the patron saint of depression and lost causes, whose feast day is on Monday - was not one "you would see every year".
It has issued an amber alert for high winds in Wales, the East and West Midlands, the South West, London and the South East and the East of England.
A yellow alert warning of heavy rain that could lead to surface water flooding and disruption is in place across much of northern Wales and northern England.
An amber warning means "be prepared", while yellow means "be aware". No warnings are currently in place at the top red level, which means "take action".
Forecasters said exposed coasts in Cornwall, Devon, Dorset, Hampshire, West Sussex, East Sussex and Kent could face the strongest winds.
The Environment Agency has warned of the possibility of surface water flooding on Monday, assessing a number of areas as "medium" and "low" risk.
A spokesman said teams were working to minimise river flood risk, clearing debris from streams and unblocking culverts.
BBC Weather presenter Jay Wynne said gusts along the south coast were already in the region of 50-60mph and there was some heavy rain spreading up through the south west and southern counties of England and the south of Wales.
The strongest winds are expected in the early hours of Monday as the storm tracks its way across the southern part of the UK but should have moved across the country to the North Sea by lunchtime.
The storm developed in an area of low pressure in the Atlantic off the east coast of the US.
Northern Ireland, Scotland and the northern counties of the UK are expected to be spared the worst of the weather.
The Metropolitan Police is urging people to use its 101 number during the storm rather than 999, unless there is a "genuine" emergency
HM Coastguard urged people to take extra care around the coasts, with waves eight or nine metres high expected in some areas.
It said conditions could be "extremely treacherous", especially on cliff tops, and urged people not to put themselves and rescue teams at unnecessary risk.
Kelly Oster-Coyle, of the Association of British Insurers, said people should do "small practical things" to prepare for the storm but insurers knows "things will be flying around" in the high winds and will be ready to pay out to customers.
Wind speeds of 115 mph were recorded during the so-called Great Storm of October 1987.
There is more information about the forecasts for Sunday and Monday on the BBC Weather, Met Office and Environment Agency websites. See BBC Travel News for up to date travel information and theHighways Agency and Traffic Wales websites for details about road conditions. BBC Local has information from your area.
Do you live in one of the areas predicted to be hit by the storm? What precautions will you be taking? Has the weather forecast altered your plans? Please send us your comments using the form below.
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