PA MediaA red weather warning for wind has been issued for Northern Ireland by the Met Office.
The entire island of Ireland is now under red warnings, which are rare and are the highest level of alert.
The Met Office says there is a danger to life.
The Northern Ireland warning will be in effect from 07:00 until 14:00 GMT on Friday.
An amber warning will also be in place in Northern Ireland from 06:00 until 21:00.
The Met Office says a red weather warning means dangerous conditions with widespread disruption.
It advises people to expect:
- Flying debris resulting in danger to life
- Large waves and beach material being thrown onto coastal roads, sea fronts and homes
- Very dangerous driving conditions with fallen trees on roads
- Power cuts affecting other services, such as mobile phone coverage
- Damage to buildings and homes, with roofs blown off and power lines brought down
- Roads, bridges and railway lines closed, with delays and cancellations to bus, train, ferry services and flights
It is the first time a red weather warning has been issued for Northern Ireland since an impact-based system was introduced in 2011.
Previous red warnings were issued on a different basis.
It is also the first time a red warning has been issued across the whole island of Ireland.
Storm Éowyn is the fifth named storm of the winter season, and follows Storm Darragh which hit on 5 December.
Winds are expected to rapidly increase on Friday morning with peak gusts of 80-90 mph (130-145 km/h) and possibly up to 100mph along some exposed coasts.
The strongest gust ever recorded in Northern Ireland was 124mph in Kilkeel in County Down on 12 January 1974.
The Met Office has advised people to stay indoors and avoid travelling by road.
A red wind warning was issued for the whole of the Republic of Ireland on Wednesday, with Met Éireann warning of a possible “danger to life”.
There are other warnings across parts of the United Kingdom.
Belfast City Airport has warned passengers to expect disruption to flights on Friday.
Republic of Ireland weather warnings
In the Republic of Ireland, Met Éireann has warned that “severe, damaging and destructive winds” are expected.
The red alert there comes into effect at various times from 02:00.
Speaking to RTÉ, chairman of the National Emergency Co-ordination Group said Storm Éowyn would “probably be among the severest storms” Ireland had ever seen.
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