A Status Yellow rainfall warning has been issued for Cork and Waterford for tomorrow.
Met Éireann said that persistent rain will be heavy, and possibly thundery, at times.
Flooding, difficult travelling conditions and poor visibility are expected.
The warning will be in effect from 3am until 6pm tomorrow.
The forecaster said the rain will develop in the south and west and gradually spread northeastwards during the day, but northeastern areas will stay dry.
