Natural Resources Wales is urging people living near or visiting the Welsh coast to be prepared for localised coastal flooding impacts on Friday evening (18 October).
This will include low lying land and roads near the coast or estuaries.
There could also be localised property flooding at some vulnerable locations.
Flood warnings for stretches of the Welsh coast are likely to be issued this Friday evening to coincide with the high tide, which in Aberystwyth will be 9.17pm this evening.
A flood warning has been issued for the tidal area of Cardigan.
The warning says: "Property adjacent to the river between Cardigan Bridge and the A487 road bridge, including The Strand, St Mary Street, Gloster Row, Pwllhai. Also the supermarket car park and adjacent properties
"Flooding is expected as a result of the combination of the high tides and weather conditions for Friday 18 October.
"The next high tide at Fishguard is expected to occur at 08:45PM. For the next high tide winds are forecast to be Force 5 from a south-westerly direction. Be careful on the car park, roads, close to the estuary and low lying land. We will continue to monitor the situation."
Similar warnings are in place for River Towy at Carmarthen Quay, Carmarthen; Tidal area at Carmarthen Bay Holiday Park, Kidwelly; Tidal area at Carmarthen Quay; Tidal area at Laugharne; Tidal area at Dale; Tidal area at Pendine; Tidal area at Lower Town Fishguard; Usk Estuary at Uskmouth and Old Town Docks; Usk Estuary at Caerleon; Wye Estuary near Tintern; Wye Estuary at Chepstow and Red Wharf Bay.
There is also a flood alert along the length of Cardigan Bay.
People are encouraged to keep updated by checking NRW’s website.
Friday evening’s tide is the highest of the current series of spring tides and water levels will be higher due to the combined effect of storm surge and localised wave action at exposed locations.
While peak tide heights will start to reduce after today, people need to remain vigilant over the weekend as stormy weather associated with Storm Ashley is expected on Sunday.
Flood alerts are likely to remain in force over the weekend for parts of the Welsh coastline. Flood alerts may also be issued due to heavy rainfall causing rivers to rise again after recent flooding. Low lying land and roads will therefore remain at risk of further localised flooding over the next few days.
Nicholas Bettinson, Duty Tactical Manager for Natural Resources Wales said: “With the potential for property flooding in low-lying coastal areas, we are urging people to prepare for flooding impacts.
“If you live near to, or are visiting a coastal area, please take extra care and keep a safe distance from coastal paths and promenades which may be affected by strong winds and spray.
“Our teams will be at key sites across Wales checking sea defences are in good working order to reduce the risk to people and their homes.”
Information and updates are also available by calling Floodline on 0345 988 1188.