Met Eireann have warned that over 70mm of rain is expected to fall over the Bank Holiday weekend.
Leinster will be the worst affected, with 40mm-70mm of rain expected to fall between Friday night and Sunday.
The “Orange Alert”, which was issued today, is warning people to be prepared for torrential rain and the possibility of localised flooding.
According to Met Eireann, the rain will develop in the South East before spreading northwards.
The bad weather is expected to ease off on Sunday, with forecasters predicting that Monday will be mostly sunny.