The Met Office is warning of severe weather during Sunday as a depression caused by the after effects of hurricane Bertha tracks over, or close to, Cornwall.
The body says that at this stage there is more than average uncertainty in the forecast, but the public should be aware of the risk of heavy rain, strong winds and large waves, sufficient to disrupt transport and make outdoor activities dangerous.
A spokesman said: "This is a particularly volatile situation, and this warning is likely to be changed as the event approaches.
According to the Met Office chief forecaster, the remains of hurricane Bertha, currently over the western side of the Atlantic this morning, will come steadily towards the UK.
Adding: "The transition from a tropical to an extra-tropical feature is a particularly hard one to forecast with confidence, and computer models continue to differ in the location and intensity of the resulting depression, which is expected to pass over, or close to, the UK from early on Sunday.
"There is the potential for widespread rainfall totals of more than 50 mm and coastal gusts of over 60 mph, along with large waves. However, the system may pass harmlessly to the south of the country. or spread heavy rain even further north, and the public are advised to keep up to date with warnings."