On Southeastern mainline services will run, but alterations and cancellations can be expected. High Speed services will also run but they are subject to delays and alterations.
A reduced service will run between London and Dartford via Woolwich / Bexleyheath / Sidcup
A reduced service will run between Dartford and Gravesend
Some trains between London Charing Cross and Gillingham may be cancelled or revised
A reduced service will run between London and Orpington via Grove Park
Trains on the Hayes Line may start / terminate at Elmers End, Clock House or New Beckenham
Trains between London Victoria and Orpington will be diverted to run to and from London Blackfriars
From London Victoria:
Southern services may be cancelled or amended as follows:
Southern services between London Victoria and Brighton are suspended for the rest of today
Services to Portsmouth/Southampton and Bognor Regis will be running but will be disrupted and delays are likely.
Services to Eastbourne/Ore and Littlehampton will be running but will be disrupted and delays are likely.
Some stopping services to Horsham will be running however you may need to use alternative services.
Services will not be running to Reigate, customers will need to travel to Redhill and use Great Western Railway services, or travel to Dorking and change there for Great Western Railway services.
The National Rail website says that Gatwick Express services are being reintroduced. When this reduced service is running trains will stop additionally at Clapham Junction and East Croydon.
Southeastern have fewer services able to run, and the services that do run may be subject to considerable delays.
The alternative travel options with tickets being accepted by other firms are:
Southern passengers may use Thameslink services, and South West Trains on any reasonable routes
London Buses will accept Southern tickets on all reasonable routes
London Underground between London Victoria and London Euston
London Midland are accepting Southern tickets between London Euston and Milton Keynes Central
There is more information on the National Rail website.
On Twitter you can follow the hashtag #PoorWeatherSouth for the latest updates.