Storm Ciara: Met Office warns of up to 80mm of rainfall
Storm Ciara has come with a further warning for rain between 15:00 GMT on Saturday until midnight on Sunday.
The Met Office expects 20 to 40mm of rain to fall across Northern Ireland, with up to 80mm over some areas of higher ground within 18 hours.
On Thursday, forecasters brought the storm's anticipated arrival time forward to midday on Saturday.
Previously, it was thought the storm would hit Northern Ireland at about 18:00 GMT.
It is set to bring strong and possibly damaging winds, with widespread travel disruption expected. Coastal areas are likely to be affected by large waves and potential flooding.
Gusts of 80 to 100km/h (50-60mph) are likely across inland areas.
They could reach speeds of 115km/h (70mph) and possibly 130km/h (80mph) in exposed hills and coasts.
Northern Ireland's government agencies met on Friday to prepare for the severe weather.
The Department of Transport's roads and rivers teams have been checking and clearing road gullies and drainage grills and staff will be on standby across the weekend.
This is the third locally-named storm of the winter season after Storm Atiyah in December and Storm Brendan last month.
Storm Brendan led to power cuts affecting thousands of customers, while part of the sea wall at Carrickfergus, County Antrim, collapsed.
In the Republic of Ireland, weather service Met Éireann has issued an Status Orange weather warning for counties in the west and the north of the country.
Gusts of wind of up to 120km/h (75mph) are expected, with the warning affecting Donegal and Mayo between midday and 4:00 local time on Saturday, and Galway between 13:00 and 18:00.
Met Éireann said the "unsettled weather with strong winds and potentially stormy conditions" look "set to continue into the early days of next week, with cold weather prevailing".
It said there was a higher risk of coastal flooding due to spring tides, high seas and stormy conditions, especially for southern, western, and north-western coasts.
A further Met Office warning has been issued for wind and snow in Northern Ireland on Monday and Tuesday, with snow mainly gathering above 150m (492ft).
Snow, coupled with strong winds, is likely to lead to blizzard conditions over high ground with lightning strikes also possible.
The warning, which comes into force at midnight on Sunday until 12:00 on Tuesday, covers counties mainly towards the north coast.