Homes and roads have been flooded and people have been urged to move their vehicles away from rivers as more heavy rain is set to raise water levels.
Parts of Pembrokeshire have been badly hit with some homes in Milford Haven under 10ft (3m) of water.
A Met Office warning to expect flooding is in force across the county and Carmarthenshire until 23:00 GMT and high tide is at 19:00.
Other parts of south and mid Wales are also at risk of flooding.
Pembrokeshire council said “a number of roads” were flooded and were being dealt with on a “priority basis” while Carmarthenshire council has warned residents and businesses in the St Clears area to be “particularly prepared”.
Natural Resources Wales said with heavy rain forecast to fall on already saturated ground, localised flooding and travel disruption could be expected.
Its teams are continuing to check flood defences and people have been told to take care near fast-flowing and swollen rivers and not to drive through flood water.
Pembrokeshire council has warned home owners and businesses in Haverfordwest town centre to prepare for possible flooding on Friday night.
More heavy rain is expected to “significantly increase” the level of the River Cleddau, with Quay Street, the Riverside, Prospect Place and properties near Cartlett Brook, expected to be most at risk.
Milford Haven and Pembroke libraries are closed, along with a number of other commercial properties.
Scolton Country Park in Haverfordwest was the wettest place in the UK on Thursday, according to the Met Office, with 45.6mm (1.8in) of rain.
On Thursday, fire crews tackled flooding inside homes in Angle, Crundale in Haverfordwest, and 10 properties in Haven’s Head and Lower Priory, Milford Haven, had to be evacuated.
Traffic Wales reported people were evacuated from Lower Priory due to most roads being flooded.
First Cymru Buses said it could not access the car park at Tesco in Lower Priory to pick up customers and several roads in Camrose, Slebech and Boncath have also been hit by flood water.
A spokesman for Dyfed Powys Police said: “Everyone is safe and there is no threat to life at this current time.”
Work has also been carried out to tackle water around a service station at Dinas Cross near Fishguard.
The amber warning for heavy rain and wind is in place until 23:00, while a yellow warning covers the remainder of south Wales until midnight.
Up to 50mm (1.97in) of rain could fall on higher ground, with wind speeds of up to 60mph (95km/h) along some coasts.
Amber is the second of three categories of Met Office warnings, while yellow is the lowest.
The Met Office said the warning meant flooding was likely and fast flowing floodwater could cause a risk to life.