Met Éireann has issued a status yellow rainfall warning for Donegal for tomorrow (Sunday).
The forecaster said heavy and intense rainfall with totals of 25mm to 40mm are expected.
The warning comes into effect from 7am tomorrow morning.
Met Eireann said river levels would be elevated as a result of the rainfall, which may result in some rivers flooding, as well as surface flooding.
Drivers are asked to take extra care when traveling tomorrow morning.
Counties Sligo, Mayo and Leitrim have also been effected.
The warning will remain in place until 9pm tomorrow night.