Met Eireann says it expects to have more precise details about the route of Hurricane Lorenzo by tomorrow.
The national forecaster has been working with the US National Hurricane Center and others to try and predict the storm's path.
No category five hurricane has ever made it this far east or north over the Atlantic.
Emergency planners will also decide today whether the National Emergency Co-ordination Group needs to meet to prepare for the storm.
Met Eireann’s Jean Byrne says there's still some uncertainty, but at the moment, it looks like the the storm will track close to Ireland and could impact on the West South and East of the country, Including Wicklow and surrounding counties.