A status orange rain warning has been issued for four counties.
The alert is in place in Londford, Leitrim, Cavan and Roscommon until 6pm this evening, with 50 millimetes of rain possible - which may lead to some flooding.
Seperately, a status yellow thunderstorm is in effect across 25 counties on the island, including Cavan and Monaghan. It runs until 9 o'clock tonight.
Met Eireann is forecasting heavy downpours of rain, and a change of localised flooding.