Met Éireann has issued a status yellow thunder warning for nine counties.
The warning, for Cavan, Monaghan, Donegal, Longford, Louth, Meath, Leitrim, Roscommon and Sligo, came into effect at 2pm today.
It will remain in place until 9pm tonight.
Met Éireann stated that there will be "heavy thundery downpours this afternoon and evening with a risk of localised flooding".
The news comes after a status yellow rainfall warning was issued for all of Connacht yesterday.
The rain warning is in place until 6pm this evening.
Met Éireann said that "heavy or prolonged showers with the risk of thundery downpours could lead to rainfall accumulations of 25 to 40mm over the period."
The forecaster said that for the rest of the country, showers "will become isolated" and tonight there will be "long clear periods".
It predicts Wednesday starting mainly dry with sunny spells, however, showers are expected in the afternoon.
