Met Éireann has issued a status yellow thunderstorm and rain warning for Leinster, Cavan, Donegal and Monaghan, which will come into effect on Saturday.
The warning will be in place from noon to 8pm on Saturday with scattered heavy showers and localised thundery downpours creating a risk of spot flooding.
Friday will be misty with fog forming in some places. Western areas will be largely dry with clear spells early on, but it will remain rather cloudy with outbreaks of rain in the east.
Another spell of persistent rain will move into the southeast and east overnight and will be heavy at times. A band of showers will also develop in western areas overnight and some of these will be heavy too.
It is expected to be a mild and humid night with temperatures not falling below 11 to 14 degrees, in light and variable breezes.
A mostly dull and misty start to Saturday with rain in the northeast and scattered showers elsewhere. Sunny spells will develop through the afternoon and evening but there’ll also be scattered heavy showers and thunderstorms, particularly in Ulster and Leinster where localised heavy downpours may lead to spot flooding. Highest temperatures of 17 to 20 degrees, with light southerly or westerly winds.
The All Ireland hurling final, which involves a clash between Limerick and Cork at Croke Park in Dublin on Sunday, looks set to avoid the worst of the weather. Matchgoers can anticipate cloudy but dry conditions with a highest temperature of 17 degrees.
Meanwhile, Thunderstorm warnings are in place for Antrim, Armagh, Down, Fermanagh, Tyrone and Derry from noon on Saturday until 10pm. Heavy showers and thunderstorms may cause some transport disruption and flooding.