The Irish meteorological service warns of "incessant falls of heavy rain overnight and for all of Saturday" from Kerry to Donegal, with "accumulations in excess of 70mm expected" particularly on higher ground.
Slightly less rain is expected in Cavan, Limerick and Cork but accumulations of up to 70mm are likely, and will result in "flooding and treacherous driving conditions" throughout the western half of the country.
A Status Orange wind warning is in effect for the West Coast, with mean wind speeds of up to 75kmh from the southwest, gusting to 120kmh and strongest in coastal areas.
Met Éireann has declared Status Yellow for wind in Cavan, Monaghan, Roscommon, Leinster and much of Munster with 100kmh gusts expected.
For those at sea, southwesterly gales will develop on all Irish coastal waters and in the Irish Sea as the day progresses, increasing to storm force this afternoon between Loop Head and Fair Head. A Status Yellow small craft warning is in effect.