A Status Orange rain warning has come into effect for Wicklow and Waterford, while a Status Yellow rain warning is active for nine other counties, with more flooding likely, according to Met Éireann.
The Orange warning came into effect at 3am and will expire at 3am, with the forecaster saying that spells of very heavy rain falling on already saturated ground combined with high river levels and high tides will lead to localised flooding, river flooding and difficult travelling conditions.
The Yellow warning for Carlow, Dublin, Kildare, Kilkenny, Laois, Louth, Wexford, Monaghan and Tipperary came into effect at 3am and will also come to an end at 3am.
Motorists in affected areas are being warned not to drive into flood water.
Wicklow County Council said that it is in “a state of readiness” ahead of the Orange warning.
In a social post, it said it has taken a number of preventative measures, including outdoor crews working to clear drains and gullies that have become blocked with flood debris; crews prepared and ready to respond to areas likely to be impacted by forecast high intensity rainfall; and stocks of sandbags have been replenished and available at depots across the county.
It added that roads subject to flooding and structural damage have been closed to traffic and that work continues to assess the scale of damage caused to the road network.
Waterford City and County Council are making sandbags available in some of their depots and are advising people to stay away from coastal areas.
‘Dangerous and unpredictable’
Wexford County Council said that it is “dangerous and unpredictable, and even shallow water can hide strong currents, debris and open drains”.
The county was badly affected by flooding from Storm Chandra last week.
The council said that roads are flooded in places where motorists might not ordinarily expect flooding.
The council has installed aqua dams along exposed parts of the quay in Wexford town ahead of high tide around 9am.
The council said that much of the spot flooding and pooling of surface water is caused by run-off from land, which combined with full drainage systems, will take time to recover.
High coastal levels will reduce the capacity for river discharge and increase flood risk in low-lying areas, especially at high tide, it said.
The council added that high spring tides for the remainder of the week, combined with strong winds and surge, may cause wave overtopping and coastal flooding in places.
Watch: Wexford County Council is preparing for ‘very high tides’ in Wexford harbour
Read more: Live: Updates as they happen
Met Éireann Meteorologist Michelle Dillon said that for an Orange warning over a 24-hour period, between 50mm and 80mm of rain has to fall “and up to double that on the windward side of mountains”.
Speaking to RTÉ’s Drivetime yesterday, Ms Dillon said coastal flooding is also a risk during the latest rain warnings because of high tides and “strong onshore winds” with easterly winds and “storm surge”.
“We’re looking at higher-than-usual spring tides, so at times of high tide we’re looking at some coastal flooding too.