It has warned this could cause severe flooding and damage to property in the affected areas, as well as difficult driving conditions.
In Northern Ireland, the TrafficWatchNI service said wind and rain are “starting to cause issues” for motorists on Saturday morning.
A tree and utility lines have come down onto the Belfast Road in Newtownards, partially obstructed the road.
In County Tyrone the Dergbrough Road, Plumbridge, is fully closed due to a fallen tree.
The Coast Road in Ballygally is also shut because of a rock fall, which is believed to be related to Storm Bert.
TrafficWatchNI is also reporting “very difficult driving conditions” on some higher areas including the Glenshane Pass, Coleraine Mountain Road, Windyhill Road in Limavady and Glenpark Road, Omagh.