Yellow warnings for snow, ice and low temperatures have also been issued across the Republic of Ireland.
Irish weather service Met Éireann has warned of hazardous travel conditions over the weekend.
A yellow alert for County Donegal lasts from 20:00 local time on Friday until 11:00 on Saturday.
Wintry showers are expected, with some snow accumulation possible, along with poor visibility and difficult travelling conditions.
A separate yellow warning for low temperatures and ice has been issued for a wide area, with the thermometer expected to drop to between -2C and -4C.
That warning lasts from 18:00 on Saturday until 11:00 on Sunday.
In addition, a further yellow warning for snow and ice covering Cavan, Donegal, Monaghan, Connacht, and Louth lasts from 18:00 on Saturday until 11:00 on Sunday.