Met Eireann has issued a Status Yellow weather warning for Donegal due to heavy rain and possibly thundery downpours.
Forecasters have warned that heavy showers and isolated thunderstorms may bring a risk of localised flooding and hazardous driving conditions today and tomorrow.
The alert has been in place from 12noon Wednesday until 3am on Friday.
A more prolonged and widespread period of heavy rain will occur later today (Thursday). Temperatures will remain warm, with highs of 17 to 20 degrees.
Donegal, Leinster, Cavan, Monaghan, Leitrim, Roscommon, Sligo, Tipperary and Waterford all stand to be affected by the stormy weather.
Tonight, northern counties will see prolonged moderate rainfall persisting through the night with occasional heavy bursts, it will become patchier later in the night.