Meteorologist Matthew Box said: "The winds will be a touch down on what we saw with Ciara but the focus is on a bit more rain".
Southern railway said high winds have the potential to damage overhead lines and tracks, for example through debris or lineside trees falling on to the railway.
John Curtin, the Environment Agency's executive director of flood and coastal risk management, said Cumbria, Lancashire and Yorkshire were the areas he was most "concerned" about.
New Zealand: RBNZ to retain a conditional easing bias - Westpac Therefore, the New Zealand currency will be reacting mostly to outside news, especially those about the virus outbreak in China. Above: Pound-to-New-Zealand Dollar rate shown at weekly intervals. "We have very low stimulatory interest rates", he added.
Media captionBBC Weather's Tomasz Schafernaker looks at the areas most likely to see severe impacts from Storm Dennis.
The country is bracing itself for Storm Dennis.
Network Rail is also advising passengers to expect delays and cancellations to services due to flooding, and to allow more time for their journeys.
"Our priority will be to try to keep the main roads safe and open as far as possible for emergency access, and provided that need is met our resources will be used wherever else they can be to help affected communities".
As of 2.30pm there were 12 flood warnings, meaning that flooding is "expected", and 97 flood alerts, meaning that flooding is possible, in place across the country.
The Met Office has stated travel disruption is likely across parts of England this weekend as Storm Dennis is expected to bring gusts in excess of 50mph.