Up to 50mm could fall in in Connacht, Longford, Louth, Westmeath, Meath, Cavan and Monaghan between Monday night and Tuesday.
Met Éireann has issued a status yellow rainfall warning, due to come into effect from 9pm on Monday night. It will remain in place until 9pm on Tuesday night.
“Heavy rainfall will lead to accumulations of 30mm to 50mm, with higher accumulations in mountainous areas.
“This will bring a risk of some river and localised flooding,” Met Éireann has warned.