Met Eireann has issued a Status Yellow Rainfall Alert this evening for Waterford and Cork.
The forecaster warns that frequent showers will merge to longer spells of rain at times and lead to accumulations of 25 to 35mm in some parts.
There is also a risk of hail and thunder during the wet spell.
The weather alert is valid from 2am on Friday morning until 2am on Saturday morning.
Status Yellow - Rainfall warning for Cork and Waterford
Frequent showers merging to longer spells of rain at times during the period, will lead to accumulations of 25 to 35mm in some parts, particularly near the south coast.
Valid Friday 02:00 to Saturday 02.00 pic.twitter.com/qHjXEIIaki— Carlow Weather (@CarlowWeather) November 22, 2018