It is expected to be downgraded to a post-tropical storm before making landfall in southern Ireland Monday morning, but U.K. Met Office forecaster Luke Miall said it could still pack "hurricane force" winds.
Ireland's Met Eireann weather service said the country's southern and western counties could get gusts of up to 80 mph (130 kph) along with heavy rain and storm surges. The U.S. National Hurricane Center said the storm could bring two to three inches (50 to 75 millimeters) of rain in western Ireland and Scotland, with coastal flooding and "large and destructive waves" where it makes landfall.
Emergency officials in Ireland said schools would be closed Monday in the eight counties expected to see the strongest winds and under a red weather alert, the highest level. Cyclists and motorists were warned to stay off the roads during the height of the storm.
Irish Prime Minister Leo Varadkar tweeted: "Defence forces being deployed in Red weather alert areas and on standby for further action tomorrow." Dublin and Shannon airports advised passengers to check flight information before travelling, while Cork airport in southwest Ireland said cancellations were likely.
Britain's Met Office said 80-mph gusts could hit Northern Ireland, which is part of the U.K., and warned of potential power cuts, flying debris and disruption to transport and phone signals. Strong winds could also hit Scotland, Wales and England.