Met Éireann has issued red weather warnings, its highest alert level, ahead of the arrival of Storm Eunice.
The storm warnings are for Cork and Kerry from 3.00am until 8.00am on Friday.
A red warning is issued when there are "rare and very dangerous" weather conditions from intense meteorological phenomena, the forecaster says.
People should take action to protect themselves and their property.
And they should follow instructions and advice given by the authorities under all circumstances, and be prepared for "exceptional measures".
As part of the red alert, damage to power lines, fallen trees and dangerous driving conditions are expected.
The forecaster says the storm will track quickly over Ireland on Thursday night and Friday morning.
It says the system will bring "severe and damaging winds".
Southwest winds will reach mean speeds over 80 km/h, with gusts "in excess" of 130 km/h, it says.
Some coastal flooding is also possible - especially at high tide.
While a status orange storm warning has been issued for Clare, Galway, Waterford, Wexford, Cork, Kerry, Tipperary, Kilkenny, Carlow, Wicklow, Laois, Offaly and Dublin.
This warning is in place from 3.00am until 11.00am on Friday.
Met Éireann says winds will reach speeds of 65 to 80 km/h - with gusts up to 130 km/h.
And a status yellow wind, rain and snow warning - issued earlier - remains in place for all other areas.