A Status Orange rain warning has been issued by Met Éireann for counties Waterford, Wexford and Wicklow.
This warning is in place from 5:30p.m on Wednesday (October 27) until 8:00a.m on Thursday.
The national forecaster has said that following heavy rain today, there will be additional significant accumulations of rainfall this evening and overnight with flooding in places.
Along with the Status Orange, there are also a number of Status Yellow rain warnings in place.
Counties Kildare, Laois, Tipperary, Carlow and Kilkenny can expect heavy spells of persistent rain that will lead to localised flooding from 5:30p.m this evening until 6:00a.m tomorrow.
A rain warning has been in place for Cork since 3:00a.m this morning and this will remain in place until 3:00a.m on Thursday. A warning has also been in place for Kerry since 1:00a.m and will remain in place until 1:00a.m on Thursday.
Even after these warnings lift, the remainder of the week is set to be largely unsettled.
After a cloudy but dry start to the night on Thursday following the end of the rain warnings, another spell of wet weather will extend from the south later, with rain becoming heavy at times.
Friday (October 29) will start wet in many areas, but the rain looks set to clear to sunny intervals and showers by afternoon for most areas.
Saturday will see further rain or showers with temperatures around normal for the time of year, with the unsettled conditions continuing through the weekend.