Storm Conall has brought heavy rain to parts of southeast England, triggering flooding which has blocked key rail lines, causing travel delays.
Commuters are being warned of heavy disruption on some routes and advised not to travel on some parts of the network this morning.
The Met Office has predicted the third named storm of the season could bring up to 50mm (two inches) of rain on Wednesday – just days after torrential rain from Storm Bert over the weekend.
The Dutch weather service KNMI named the new storm, Conall, as it headed towards the south of England bringing an area of low pressure.
After heavy rain in southern counties, it will deepen further to bring strong winds across the Netherlands later on Wednesday and into Thursday.
Get the five-day forecast where you are
A Met Office yellow rain warning has been issued for southern England, including Kent, Sussex and the Isle of Wight until midday.
Essex, Surrey, Hampshire, Dorset, and parts of London will also be affected.
A previous warning around around Plymouth in Devon has now been lifted.
Between 15 and 20mm (0.6-0.8 of an inch) of rain is likely with 30-40mm (1.2-1.6 of an inch) in some areas and a lower chance of 50mm in parts of the South East
Some travel disruption and flooding should be expected, the Met Office said.
Disruption to rail routes
Flooding has hit several train lines across the region. Thameslink services are being affected between London Blackfriars and London St Pancras International.
Commuters are being warned of heavy disruption in and out of central London. People are being advised not to travel on this route this morning.
South Western said there are no trains between Ascot and Aldershot because of flooding in Bagshot.
Great Western and South Western are also reporting delays between Cardiff Central / Bristol Temple Meads and Portsmouth Harbour. There is also disruption between Gloucester / Bristol Temple Meads and Southampton Central.
Flooding and a fallen tree are affecting trains there.
There are problems between Guildford and Wokingham / Farnham. Trains are expected to be cancelled or delayed until 11am.
Meanwhile no trains will run between Tonbridge and Redhill on Southern trains.
And on the Isle of Wight, the line between Ryde Esplanade and Ryde St Johns Road is expected to be closed until later this morning.
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Storm Bert clean-up operation begins
On Wednesday morning there were around 100 flood warnings and 153 flood alerts in place – the vast majority in England.
A severe flood warning, meaning there is danger to life, was still in place in Billing Aquadrome holiday park and the surrounding parks next to the River Nene in Northampton.
Storm Bert clean up continues
It comes as communities are still clearing up after Storm Bert, which brought torrential rain and winds of more than 80mph, turning roads into rivers and flooding hundreds of homes.
Earlier, the Met Office warned more flooding is “likely” to hit the UK this week, with further potentially heavy rain arriving across southern areas alongside colder temperatures on Wednesday.
Chris Wilding, of the Environment Agency, said “significant flooding impacts” are probable in parts of Northamptonshire, with “minor” flooding on the River Severn.
Flooding impacts are not expected to worsen in Yorkshire and the West Midlands over the next few days.
Additional minor river and surface water flooding impacts are also “probable” in parts of the south and east of England from late on Tuesday and through Wednesday, Mr Wilding said.
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Tricky landings for Storm Bert planes
There were more than 90 flood warnings and more than 120 flood alerts still issued across the UK as of Tuesday evening.
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The naming of storms is shared by the KNMI, the Met Office and Ireland’s Met Eireann to make communication of severe weather easier.
The storms list – first launched in 2015 – for each year generally runs from early September until late August the following year, coinciding with the beginning of autumn.