This will cause "exceptionally high waves", the Met Office predicted.
Meanwhile, the Environment Agency issued 70 flood warnings covering every region, urging people to take immediate action as flooding was "expected"
The agency estimated that about 220 properties have been flooded so far, miles of coastline have been battered and roads and fields across the country left under water.
The transport network has also been hit, with roads closed and trains delayed or cancelled in many areas.
First Great Western encouraged passengers travelling in Cornwall, Devon, Somerset, Dorset and Hampshire today to begin their journeys as early as possible due to the risk of flooding.