Storm Austen is due to reach the UK this week, bringing powerful winds that could reach 70mph in affected areas.
The Met Office expects the storm to arrive on Thursday night, 22 October, with the strongest winds occurring after midnight on Friday, 23 October.
It is forecast to approach from the south-west, with the first effects anticipated late on Thursday.
Amber and yellow warnings cover southern Wales and south-western England.
Forecast gusts of 50mph to 60mph are likely, while coastal and exposed areas could experience winds of 70mph or more.
Heavy rain is also expected and may create difficult travelling conditions.
Oxfordshire is expected to avoid the storm’s most severe effects, although neighbouring counties, including Wiltshire and Oxfordshire’s surrounding areas, are set to experience adverse conditions.
Heavy rain is forecast to continue throughout Thursday and remain in place into next week, with several very wet days expected.
The Met Office has warned that strong winds could lead to disruption across transport networks, longer journey times and cancellations.
Road, rail, air and ferry services may be affected, and some roads and bridges could close.
Power cuts are possible, potentially interrupting other services such as mobile phone coverage.
Buildings may sustain damage, including tiles being blown from roofs.
Flying debris could cause injuries or threaten lives, while large waves and beach material thrown onto sea fronts, coastal roads and properties may also result in injuries or danger to life.