Gale force winds and high tides along parts of the coastline could lead to flooding in some parts of Wales and southern England.
The west and south coast of Wales and the coasts of Devon, Cornwall and Somerset are likely to experience gusts of up to 60mph, forecasters said.
The Environment Agency said strong westerly winds would cause stormy seas which, combined with some of the highest tides of the year, would lead to high sea levels and spray coming over sea walls.
Low-lying coastal roads, farmland and isolated houses could be vulnerable to flooding, but the agency is also warning of the possibility of more significant problems.
There are currently 25 flood warnings in place, mostly for coastal areas in the South West and Wales, with one also in the North East, and high tides are likely to lead to more warnings being issued.
Gemma Plumb, a forecaster with MeteoGroup, the weather division of the Press Association, said there would be gusts of 50 to 55mph throughout the day along the south west Wales coast and would reach up to 60mph in places, while in Devon and Cornwall they would be between 40 and 55mph.
The Met Office said winds were expected to increase to "gale or severe gale force" on exposed parts of the coast, which could lead to localised disruption to transport.
The Environment Agency said its teams had been out checking flood defences and closing tidal gates ahead of the high tides, and warned people to be careful driving or walking along the coast over the next few days.
People should be particularly careful on exposed areas, where there is a risk of being swept away by waves or being hit by debris thrown up by waves, the agency added.