High tides, gales force winds and up to an inch-and-a-half (40mm) of rain could cause coastal flooding in parts of the Westcountry, the Environment Agency has warned.
The south coast along Dorset, Devon and into Cornwall was said to be most at risk with spring tides and strong south easterly gales combining to hit communities today and over the weekend.
Agency gangs have been out checking flood defences and closing tidal flood gates at locations including Truro, Polperro and Plymouth.
Staff are also closely monitoring wave buoys and checking sea conditions.
Offshore waves of up to 10 metres were expected last night as winds picked up.
Tidal surges of up to half a metre above predicted spring tides were set to cause overtopping and spray either side of high tide at some coastal locations. The stormy conditions will coincide with the arrival of rain early tomorrow. High tides start at Newlyn at around 5am, moving up the coast and peaking in Dorset at 11am.
The public have been advised to avoid seafronts, quaysides and jettys because of overtopping by waves and the subsequent risk of injury.
Spokesman Nick Roseveare last night said: "We are keeping a close eye on conditions around our coastline and will issue flood warnings if the risk of flooding increases."
"The critical periods will be the early morning tides over the next three days.
"If they coincide with rain, there's a risk of tide-locking where water is held in rain-swollen rivers and cannot escape into the sea because of the high tides. We urge people to remain vigilant."