A status yellow warning for rain has been issued for Donegal.
Met Eireann is warning of heavy rain, persistent at times with accumulations of 30 to 60mm tomorrow.
The rain is expected to ease off for a time in parts tomorrow before heavy spells return in the evening.
The forecaster says there is the potential for localised flooding.
The warning comes into effect tomorrow at 12am and will remain In place until 6am on Wednesday.