Authorities in Britain and Ireland say the remnants of Hurricane Ophelia could bring disruption and damage as the work week gets underway.
Ophelia was a category 2 hurricane on Sunday as it moved northeast across the Atlantic, with sustained winds of 105 mph (169 kph).
John Wylie of the Met Office warned there is the potential for danger to life.
It is expected to weaken to a storm before hitting land Monday, but U.K. Met office forecaster Luke Miall says it could still pack "hurricane-force" winds.
Ireland's Met Eireann says western counties could get gusts of up to 80 mph (130 kph), with heavy rain and storm surges. The National Emergency Co-ordination Group warned that it is the most powerful storm system to hit the country in 50 years.
The Department of Education has urged schools in Galway, Mayo, Clare, Cork and Kerry not to open, according to the Irish Times, and sandbags have been distributed in some areas in case of coastal flooding.
Britain's Met Office has a similar warning for Northern Ireland, and warns of potential power cuts, flying debris and disruption to transport and phone signals.
Monday's weather will see "huge contrasts", according to BBC Weather, with the strong gusts of wind travelling over the Irish Sea and heading north to central and southern Scotland.
Forecasters have said Eastern England should expect unseasonably warm weather however, due to the storm, with temperatures of 22C or 23C on Monday.