Met Eireann has issued warning for "intense rain" set to batter four counties on Sunday.
The Status Yellow alert, which was announced on Friday evening, will be in place for Donegal, Leitrim, Mayo and Sligo.
The caution will come into effect at 7am on Sunday lasting until 9pm that night.
Up to 40mm of "intense rainfall" is expect throughout the day, which may result in both river and surface flooding.
Meanwhile, the rest of the country looks set for a mixed-bag weekend.
A forecaster said: "Saturday morning will be mainly dry with sunny spells for the most part, it will become cloudy early however in the east.
"During the afternoon scattered showers will develop in the west, while rain will develop in the northeast through the afternoon and become persistent in the north and northeast during the evening hours. Highest temperatures of 9 to 13 degrees."
The rain will worsen overnight on Saturday with Met Eireann warning it will become "heavy at times" and will bring the risk of some spot flooding.
Sunday is when things will really start to take a turn.
A forecaster added: "It will start off wet in most area with heavy and prolonged rain leading to a risk of localised flooding.
"Eastern parts will begin to clear during the morning, however the rain will persist in the west. Highest temperatures of 11 to 15 degrees in moderate to fresh, gusty northwest winds, which will ease light northerly as the rain clears."
