Natural Resources Wales is urging people near the Wales coast to be prepared for flooding.
The warning comes as high tides combined with forecast gale force winds could see a storm surge that would raise the level of the sea by up to a metre above high tide. This surge could cause overtopping of defences in places.
Although last month’s tides, which caused flooding in many parts of North Wales, were higher in North Wales this is expected to be the highest tide to hit the whole Welsh coast since 1997.
While the threat extends along the entire Welsh coastline, Natural Resources Wales is particularly keeping a close eye on Newport in south Wales, (specifically the Crindau area), the west coast (specifically Barmouth, Borth, Carmarthen Bay and Haverfordwest) and the north Wales coast from Kinmel Bay to the Dee estuary.
While the exact detail changes as the high tides approach, it is possible that Severe Flood Warnings, the highest level of warning, will be issued in these areas and possibly others.
Flood Warnings are expected to be issued in many places along the coast.
High tide will start at Milford Haven at 7.20am and will reach Newport (south Wales) at around 8.15am, Barmouth at 9.20am and reach Flintshire by mid day.
Further high tides will pose a similar, but slightly reduced threat some twelve and twenty four hours later.
Emergency response workers from Natural Resources Wales will be at key sites across the area checking defences are in good working order and making sure any drainage grids and screens are clear, to reduce the risk to people and their homes.
It is opening incident rooms in many parts of Wales to prepare.
A spokesperson for Natural Resources Wales said:
“As the Met Office forecasts gale force winds, we are monitoring sea levels and weather conditions and will issue flood warnings to registered properties in those areas at risk.
“We have already been speaking with our partners from the emergency services and all the local authorities which might be affected so they can put their plans into action.
“We are also warning people to avoid visiting the sea front due to the risk of being swept away by large waves or hit by wave and wind-blown debris.
“Flood water can also be extremely dangerous, and people should not attempt to walk or drive through it unless instructed by the emergency services.”
Meanwhile a further tidal surge and large waves predicted for Sunday and Monday could cause further problems. Natural Resources Wales will monitor the situation and issue further updates as required.
Flood alerts and flood warnings are updated on the Natural Resources Wales website every 15 minutes.
Information and updates are also available by calling Floodline on 0345 988 1188. People can also register for free flood warnings either by calling the Floodline number or at the Natural Resources Wales website.