A Status Yellow rainfall warning has been issued for most of Munster including Clare and for the Connacht counties.
Met Éireann is warning of heavy and persistent rain through to Friday morning which will lead to some flooding and disruption. Accumulations of 30mm to 60mm are expected widely, with higher values in mountainous regions.
The warning is valid until 6.00am on Friday.
Flooding has already been reported on the N85 Ennis to Ennistymon road at Kilnamona.
Motorists are asked to exercise caution as further flooding is possible.
Meanwhile, a Status Yellow gale warning has been issued for coastal areas.
The weather service has warned that: “Southwest winds will reach gale force today and early tonight on Irish coastal waters from Wicklow Head to Loop Head to Malin head and on the Irish Sea.”