Met Eireann has issued two thunderstorm warnings for all counties across Ireland with miserable conditions forecast.
The first Status Yellow alert will be in place over a five-hour period from 9pm on Saturday until 2am on Sunday.
The national forecaster says there will be thundery outbreaks of rain with possible lightning and localised flooding.
Among the counties affected are Galway, Mayo, Roscommon, Sligo and all of Munster.
A second Status Yellow thunderstorm warning has also been issued for Leinster, as well as Cavan, Donegal, Monaghan and Leitrim.
This will be effect from 1am until 4.30am on Sunday.
It comes as the rest of the country is also set to be hit with awful weather over the next few days.
Met Eireann says thunderstorms, "cyclonic" winds and a risk of flooding can all be expected in many areas over the weekend.
Saturday will be "mostly bright and fresh" in the morning with "good sunshine and just a few passing showers in light to moderate west to southwest breezes".
However, cloud will increase in the west in the afternoon with rain extending from the Atlantic through the evening as southeasterly winds increase fresh to strong and gusty, with highest temperatures of 9 to 13C.
It will turn windy on Saturday night with heavy showery outbreaks of rain in the west, spreading to all areas overnight.
A forecaster said: "There will be a chance of isolated thunderstorms and the risk of localised flooding. Southeast winds will be fresh to strong and gusty, but as the rain clears northeastwards, allowing clear spells and scattered showers to follow into southern parts, the winds will veer southerly and moderate for a time.
"Later the winds will further veer westerly in the Munster towards morning and increase strong and gusty with gale to strong gale force winds on some Atlantic coasts. Lowest temperatures of 4 to 8 C, or a little cooler locally in Ulster.
"Starting very windy in the southwest on Sunday morning with blustery heavy showers, while elsewhere will see clear spells and just isolated showers, as winds fall light to moderate cyclonic variable.
"However a band of showery rain and stronger winds will gradually lift northeastwards across all but Ulster during the day with gusty conditions at times.
"Cyclonic variable winds, strongest from the west reaching strong to near gale and gusty at times in southern parts with gales along the coast. Highest temperatures of 9 to 13C."
Outbreaks of showery rain will slowly clear northeastwards overnight on Sunday, with drier conditions and with clear spells following from the southwest. Lowest temperatures will be between 4 to 8C as fresh and gusty westerly winds gradually moderate.
