Met Éireann have issued a weather warning for six counties.
The status yellow rainfall warning was put into place at 10am on Saturday, and will last until 10pm the same evening.
It covers Longford, Louth, Westmeath, Meath, Cavan and Monaghan.
A forecaster said:
“Slow moving bands of rain or heavy downpours today will lead to spot flooding.
“Rainfall acumulations of 25 to 40mm possible.”
Looking towards the weather for the rest of the weekend, Saturday is set to see heavy scattered showers merging into longer spells of rain through the day, with a risk of some flooding.
A forecaster warned that further thunderstorm activity is also expected, with temperatures hitting between 16C to 19C.
“Heavy showers or longer spells of rain continuing [Saturday night], mainly in Munster and Leinster, with drier conditions moving into parts of the north.
“Lowest temperatures of 11C to 13C, with moderate west to northwest winds fresh to strong at times along coasts.”
The Met Éireann forecaster said there will be more “generally unsettled and showery conditions”, and that it will feel cooler – and less humid – into early next week.
Sunday is predicted to be “fresher and cooler”, with showery rain slow to clear the eastern half of the country.
There will be drier, brighter conditions with isolated showers in the west, which will gradually extend eastwards through the day.
It will also feel cooler than recent days, with the highest temperatures ranging from 14C to 17C.
Looking towards Sunday night, the forecaster said:
“It will be mostly dry with clear spells, with just isolated showers near Atlantic coasts. Cool with lowest temperatures of 7C to 9C.”