A yellow weather warning has been issued for heavy rainfall and snow for the west and south west of the country over the weekend.
In Mallow, flood defenses have been put up as a precaution and it is expected Fermoy may also take these measures.
Heavy showers are expected across the nation and also rainfall accumulations of 30-40mm.
The worst affected areas are expected to be Connaught, Donegal, Clare, Cork, Kerry and Limerick.
The RSA has issued some advice for drivers who may be out in the weather.
While driving in wet and flooded conditions drivers are reminded it takes longer to stop a vehicle on wet roads, so slow down and allow extra distance between you and the vehicle in front of you.
Drive with dipped headlights at all times.
Be aware of the danger of aquaplaning, especially on roads with speed limits of 100km/h and 120km/h.