The Status Orange wind warning for Mayo, Galway, Sligo, Leitrim and Donegal has been extended until midnight tonight.
Met Eireann says that, as Storm Brendan tracks away from Ireland, southwesterly winds will gust to between 100 and 130 km/h, higher in exposed areas.
There's also a significant risk of coastal flooding due to the combination of high spring tides and storm surge.
Storm Brendan caused travel disruption today at Ireland West Airport Knock, with a number of flights diverted or cancelled, while a number of schools remained closed across Mayo and Galway.
Hundreds of homes and businesses across Co Mayo have been hit by power outages as a result of Storm Brendan, with outages reported this evening in Belmullet, Ballinrobe, Claremorris, Westport, Ballina and Charlestown, while a number of outages are also being dealt with across counties Galway and Sligo.
In Mayo, the highest gusts of 122 and 124 km/hour were recorded about 4pm this afternoon off Belmullet - yet despite the extreme winds since early morning, Mayo County Council says only minimal damage has been caused.
A number of trees fell in the Claremorris, Balla and Kiltimagh areas of East Mayo, while the R313 Belmullet to Blacksod regional road remains closed, after storm damage to a section of the road.
Homes and businesses in Galway are bracing themselves for high tide this evening just after 7 o'clock.
This morning passed without incident, but Gary McMahon from Galway City Council says the tail end of Storm Brendan could bring flooding with it: