A 48-hour status yellow rainfall warning has been issued for four counties in the north-west.
The alert for Donegal, Leitrim, Mayo and Sligo, will come into effect tomorrow morning at 9am.
Heavy rain and blustery conditions are expected to last until the same time on Monday morning.
Forecasters predict spot flooding with up to 60mm of rain.
Met Éireann said the heaviest rain will fall over mountainous areas with a risk of flash flooding.