A Status Orange thunderstorm warning has been issued for four counties in the northwest.
Met Eireann has said slow moving thunderstorms bringing heavy downpours and potentially large hail can be expected in Donegal, Leitrim, Mayo and Sligo.
The warning is to remain in place from 3pm today to 9pm tonight.
The thunderstorms could lead to flash flooding, difficult traveling conditions and damage to power lines.
Meanwhile, a Status Yellow thunderstorm warning is also in operation for Cavan, Donegal, Connacht, and Longford.
Heavy downpours with thunderstorms and hail are forecast between 2pm this afternoon and 9pm tonight.
Elsewhere, the UK Met Office has issued a Yellow thunderstorm warning for Fermanagh, Tyrone and Derry.
That warning is in place since 1pm and remains valid until 9pm tonight.
