Storm Dudley will bring long spells of rain, spot flooding and very strong winds over the next 24 hours.
A Status Yellow Wind Warning comes into effect at midday for the entire country and is due to last until the same time tomorrow.
Gusts of up to 110 kilometres per hour are forecast for exposed coasts and on high ground.
Preparations are being coordinated by the State's weather response team, which's due to meet again this afternoon.
Met Eireann forecaster, Gerry Murphy, says the unsettled weather will continue for a number of days.
"On through the latter part of Thursday night an Friday, we have another storm depression moving very close to us, Storm Eunice and that has the potential to bring very strong winds mainly to the south of the country.
"As well as that, as it tracks over us there is a significant chance of some snow over much of the country through Thursday night and Friday.
"The highest amount of snowfall is most likely to be over central and northern parts."
