Gales of up to 80mph have been forecast for parts of Cornwall on Monday with flooding expected in some areas.
The Met Office has issued a yellow alert ahead of heavy rain and wind.
It says the south west of England, Wales and Scotland will be the worst affected.
PM David Cameron has urged councils to draw up “robust plans in case of bad weather and flooding over New Year.’’
The Met Office said heavy rain was expected to spread across south-west England and south Wales on Sunday night into Monday morning.
Winds of 60 to 70mph are likely in Wales and areas of south-west and southern England, while exposed areas such as the Isles of Scilly, could be hit by gales of up to 80mph.
“With ground already saturated over much of this region, the public should be aware of the risk of further local flooding,’’ the Met Office said.
Mr Cameron tweeted on Saturday: "I've asked the Dept for Communities & Local Govt to ensure councils have robust plans in case of bad weather and flooding over New Year."
A Downing Street spokesman said ministers had held a Cobra meeting in the morning "as part of the government's ongoing work to deal with the severe weather and floods".
Those taking part in the virtual meeting were housing minister Kris Hopkins, energy minister Baroness Verma, business minister Lord Livingston and officials from the Environment Agency.