Police have issued a warning of flooding in parts of Belfast and other parts of Northern Ireland on Friday.
They have warned people who live or work in the Clarendon Dock, Corporation Street and Sailortown areas of north Belfast to take precautions.
They have said the risk of flooding in east Belfast, Londonderry, Killough, Newcastle, Newry, Larne and Strangford has been slightly reduced.
The river Bann has burst its banks and flooded parts of Coleraine town centre.
The Met Office has issued a yellow warning for rain, winds and high tides.
Police are co-ordinating the operation in anticipation of a tidal surge at midday on Friday and over the weekend.
A spokesman said police were more confident planning and preparation work carried out on Thursday could help to prevent any serious flooding in the Sydenham area of east Belfast.
A councillor for the area, the PUP's Dr John Kyle said: "The priority last night was to act to try and prevent the river overflowing, so the banks of the Connswater river have been raised and the flood barrier from Victoria Park through the underpass has been raised as well.
"Several thousand sandbags were made available and several hundred residents availed of them last night."
The Northern Ireland Executive is meeting on Friday morning to discuss contingency plans. First Minister Peter Robinson was also involved in planning with police and other agencies late into Thursday night.
Assistant Chief Constable Stephen Martin said it was a "very fluid situation".
"We are working as much as we can to try to prepare ourselves for potential flooding in those areas," he said.
"During the course of today (Thursday), we have distributed many thousands of sandbags, with our colleagues in the other agencies, to protect the rivers around the Sydenham area.
"We are working with the health trust to try to identify vulnerable people who live in that area.
"We are also putting in preparations and plans, in the event - although we are not there yet - we recommend people evacuate their homes in that area."
If homes are evacuated, Belfast City Council will provide emergency centres, he said.
Coastguard teams in counties Antrim and Down are also on standby amid fears of flooding in those areas, which include the seaside resort of Newcastle.
Assistant Chief Constable Martin added: "The combination of heavy rain, strong winds and high tides beginning tomorrow (Friday) and lasting throughout the weekend has created the potential for flooding in a number of coastal areas across Northern Ireland."
The Police Service of Northern Ireland is co-ordinating a team that includes the Office of First Minister and Deputy First Minister, Belfast City Council, Northern Ireland Fire and Rescue Service, the Rivers Agency, Belfast HealthTrust, Road Service, Northern Ireland Water, Northern Ireland Electricity, BT and Translink.
Police have urged people to stay way from coastal paths and walkways and to drive with extreme care.
P&O Ferries have cancelled a number of sailings between Larne and Cairnryan on Friday. Passengers are advised to check updates on their website.
Stena Line has also cancelled sailings between Belfast and Cairnryan and Belfast and Liverpool and all Rathlin island ferry services have been cancelled for the day.
The Bangor to Belfast railway line was blocked by a fallen tree at Seahill overnight, but the line has since reopened.
In Dunmurry on the outskirts of Belfast, Kingsway (the Belfast to Lisburn Road) was closed for a short time overnight due to a fallen tree. It has also reopened.
In Londonderry, the Foyle Bridge has been closed to high-sided vehicles because of strong winds. A 30mph speed limit has been introduced for all other vehicles.
The underground car park at Belfast's Victoria Square shopping centre has been closed as a precaution.
Anyone who wishes to report flooding can call a flooding incident line on 0300 2000 100 or the police non-emergency line on 0845600 8000.