Residents in part of East Belfast have been warned to prepare for flooding because of high tides and heavy rain predicted for tomorrow.
Tidal surges are predicted for midday tomorrow, Saturday and Sunday across the North and police asked members of the public to avoid coastal paths and to drive with extreme caution.
High risk areas include the densely-packed residential streets of Sydenham in the east of Belfast and around the docks.
Police are coordinating a major planning operation involving many public services.
Other areas that could be affected to a lesser extent than Belfast include Larne, Newry, Newtownards and Clough in counties Antrim and Down.