A yellow rain warning will come into effect later tonight.
Up to 50 millimetres of rain is expected in parts of the midlands over the next 24 hours.
A weather warning has been issued for 11 counties, including Westmeath, Longford and Meath.
The yellow rainfall alert comes into effect at 9 o'clock tonight.
Alan O'Reilly, from Carlow Weather, says there's a risk of flooding: