Strong winds and heavy rain predicted for Monday could cause disruption across Wales and southern England, according to forecasters.
The Met Office issued an amber alert for wind and there is also concern that heavy rain could cause flooding.
It warned people to "be prepared for the risk of falling trees as well as damage to buildings and other structures" caused by strong winds.
There is uncertainty about the timing of the storm at this stage.
But Nick Miller from the BBC Weather Centre said it "could be a particularly nasty weather system", adding its "most likely track" was through the middle of England of Wales.
Forecasters say there is potential for gusts of wind over 80mph, especially on exposed coasts in Cornwall, Devon, Dorset, Hampshire, West Sussex, East Sussex and Kent.Rain warning
Northern England, the Midlands, southern England and Wales have also been issued with a yellow warning for rain on Monday.
Yellow alerts are the lowest level of the three warnings.
The Met Office said people in those areas should "be aware of the potential for surface water flooding" because of the rain.
The Met Office's chief forecaster said: "A strong, high-level jet is expected to engage warm low level air to give rise to a rapidly moving low pressure system later on Sunday.
"This is expected to run north-eastwards, probably across England and Wales, with very strong winds on its southern and western flanks.
"There is the potential for gusts of over 80 mph, especially on exposed coasts, both in south-westerly winds ahead of the low and west to north-westerly winds behind it."