Poor weather, with winds gusting up to 70mph, is likely to result in ferry cancellations or delays between Aberdeen and Lerwick over the next few days.
NorthLink Ferries said anticipated strong winds and unfavourable port conditions over the weekend could impact on its sailings, with both passenger and freight services expected to be cancelled on Friday and Saturday.
The advance warning applies to both passenger services and freight vessel services between Aberdeen, Kirkwall and Lerwick.
NorthLink said it was providing notice of the anticipated disruption to allow customers to consider their options.
Where possible service cancellation decisions will be made by 11am each day and posted on the NorthLink website www.northlinkferries.co.uk and on the sailing information line 0845 6000 449.
However, as conditions change services may be cancelled later in the day and potentially after the scheduled departure time where the prevailing conditions are not favourable.
Where a scheduled service departure is delayed awaiting improvement in the conditions then passengers will be embarked as normal and kept informed but there will come a time at which the service will be cancelled and customers will have the option of disembarking and making alternative arrangements or being rebooked on the next scheduled departure.
NorthLink apologised for the inconvenience to customers caused by the bad weather.