A second yellow thunderstorm and rain warning has been issued for Ulster, Connacht and north Leinster from 9am on Saturday until midnight on Sunday.
Heavy, slow-moving and thundery showers leading to further localised flooding and hazardous driving conditions are expected.
The alert follows another yellow thunderstorm and rain warning, which was in place for Connacht, Ulster, north Leinster and north Munster and expired as of 9am on Saturday.
The highest temperatures on Saturday will reach 15 to 19 degrees while blustery winds are expected on western and southern coasts.
Met Éireann said there will be further heavy showers on Sunday with a changeable picture following into next week.
Heavy showers are forecast to continue on Saturday night, merging into longer spells of rain at times across the northern half of the country.
The weather is expected to be drier further south, with lowest temperatures ranging from 12 to 14 degrees in “moderate to fresh westerly winds, strong on western coasts”.
Forecasts say it will “remain showery” on Sunday, heaviest and most frequent over the northern half of the country.
Further heavy showers will move into Munster during the afternoon, while the weather will be drier across the middle of the country with “good sunny spells” and temperatures of 16 to 20 degrees, mildest in the east.
Weather conditions will remain mixed and unsettled next week, with scattered heavy showers and some sunny spells expected.
Tuesday and Wednesday look set to have the best of the good weather next week with highs of 21 degrees and some sunny spells.
Meanwhile, the public has been advised not to swim at a number of beaches across the country, including at Front Strand Beach in Balbriggan, north Dublin, for the next two days, and at beaches in Mayo, Donegal and Kerry due to adverse weather conditions.
The do-not-swim notice at Malahide beach has been extended due to a storm water overflow on Friday evening, following adverse weather conditions.
Fingal County Council said further sampling at Malahide and Balbriggan will take place on Sunday with results due on Monday.
Malahide beach remains open but beach users are asked to respect the do-not-swim notices as they were “put in place to ensure that the health of bathers is not compromised”, the council said in a statement.
Swimming remains prohibited at Merrion Strand in Sandymount as it was deemed to have poor water quality over a number of successive years.
Members of the public can check for water quality at any of the monitored bathing waters in Ireland by accessing the Environmental Protection Agency website at www.beaches.ie or by checking the notice board at the entrance to each beach.