Up to 40 millimetres of rain is expected in parts of country.
A Yellow rain warning has been issued for the midlands.
Met Eireann is also expecting gusts of 100 kilometres per hour and up to 40 millimetres of rain in parts tomorrow as the remnants of Storm Alex hit the country.
Three status yellow alerts come into effect tomorrow between 6am and 11pm.
Fifteen counties in the east, including Laois, Offaly and Westmeath, along the Atlantic coast are covered by the warnings.
Alan O'Reilly from Carlow Weather says the direction of the weather system's unusual for Ireland: