Met Éireann forecaster Joanna Donnelly said a spell of heavy rain today would be “significant” for those in areas already flooded.
Temperatures dropped to just below freezing last night, resulting in widespread ground frost and icy patches on untreated surfaces. Another band of rain is expected to reach the South-West by mid-morning, bringing persistent and, at times, heavy falls.
Ms Donnelly said that the weather was “very typical” for the time of year but, because the ground was already saturated, problems caused by flooding would persist.
Met Éireann is forecasting more heavy rain tonight in Leinster and Ulster but clearer conditions further west will soon spread to these provinces.
It will be another frosty night tonight and tomorrow, and Western and Southern counties will have showers of rain or hail. It will be mainly dry and bright in the East.
Showers will persist in the West and South tomorrow night and will tend to spread further north and east as the night goes on, turning sleety in places and perhaps resulting in some icy patches.
Friday will be another day when rain showers will mostly affect western and southern counties, while other areas will be drier and brighter.
On Friday night, rain showers are likely to become more widespread across the country, largely preventing frost. The showery theme will continue on Saturday and Sunday for Western and Southern counties but the rest of the country will be mainly dry and fairly bright.
Sharp night frosts are likely at the weekend and there will be a danger of icy surfaces in many areas.
Meanwhile, Met Éireann’s 2015 weather report confirms the wettest conditions across the 12 months came in December, where parts of the south reported 300% or more of the normal rainfall.
Met Éireann’s December report shows Cork Airport experienced its wettest December since the weather station opened in 1962. Cork also reported its dullest December in nearly 25 years with just over 24 hours of sunshine in total.
It was warmest in Sherkin Island, Co Cork, where the average monthly temperature was just over 10C.