Met Eireann has issued a status yellow rainfall warning for Connacht, Longford, Louth, Westmeath, Meath, Cavan and Monaghan.
The warning is in place from 9pm on Monday until 9pm on Tuesday and it states that "heavy rainfall will lead to accumulations of 30 to 50mm, with higher accumulations in mountainous areas. This will bring a risk of some river and localised flooding."
With conditions set to deteriorate, the next 24 hours are set to be wet and windy with prolonged rain spreading from the southwest later this evening.
The rainfall is set to be heaviest in the west and southwest.
Tonight will see widespread rain, heaviest and most persistent across the west and north midlands with some local flooding possible.
As for Tuesday, it's set to be a wet and breezy morning with widespread rain, heaviest over the northern half of the country with a continued risk of localised flooding.
There's set to be a reprieve in the afternoon as the rain becomes more intermittent and showery in the south, but there will still be some heavier bursts at times.
A cold day for Ulster is on the agenda with afternoon high temperatures of just 3 to 6 degrees, but it's set to be milder elsewhere with highs of 7 to 11 degrees.
The wet conditions will carry into Tuesday night with outbreaks of rain continuing in many areas overnight, with the chance of sleet over the northern half of the country.
However, it's set to be dry over much of Connacht and Ulster by Wednesday morning. Frost will set in quickly after dark in the northwest, with lows of between -2 and +1 degrees in Ulster and north Connacht.
It's expected to be warmer elsewhere with lows of 3 to 7 degrees.
