A Status Yellow thunderstorm warning has been issued for counties Carlow, Dublin, Kildare, Kilkenny, Laois, Louth, Meath, Offaly, Westmeath, Wicklow and Tipperary.
The Met Éireann warning is in place from noon on Monday until 9pm. Potential impacts include spot flooding and hazardous driving conditions.
The forecaster has indicated there will be a combination of sunny spells and showers today.
The showers will become widespread and heavy during the afternoon with thunderstorms and spot flooding likely in parts of Leinster and Ulster.
The heavy showers will mostly clear by nightfall. Highest temperatures are forecast to be 14 to 20 degrees, warmest in the east, with light to moderate southwest breezes.
Tonight will be mainly dry with clear spells as showers become isolated. Some mist patches will develop. Towards morning, more heavy showers will develop near the west coast. Lowest temperatures of 7 to 10 degrees in a light southwesterly breeze are forecast.
Met Éireann said showers will become widespread again on Tuesday. It forecasts highest temperatures of 13 to 16 degrees on Tuesday, with a mostly cloudy night with showers or longer spells of rain.
Wednesday will be a showery day with some heavy and possibly thundery downpours, and there will be some sunny breaks at times too.
Friday is forecast to be mainly dry, with current indications suggesting next weekend will be changeable with some rain or showers at times but dry bright periods occurring too with sunny spells.