Emma Skinner, who is 19 years old, was last seen at around 12.20pm on Saturday 19 November 2022 on Boundary Road.
She is described as five feet eight inches tall, of slim build and with below-the-chin length brown frizzy hair, which she is wearing in a ponytail. She is wearing black clothes and is carrying a cream-coloured rucksack.
Chief Inspector Glen Doran, of Dorset Police, said: “Emma unexpectedly took off from the person she was with and disappeared.
“Since then, we have been searching for her and have conducted a number of enquiries, but have so far been unable to establish where she may have gone.
“Before she disappeared, Emma mentioned that she wanted to get to Weymouth, but it is unclear whether she has managed to do so.
“I am hoping that somebody may have seen her since her disappearance and can help us establish where she might be.”
Anyone with information or knowledge as to Emma’s whereabouts is asked to contact Dorset Police at www.dorset.police.uk/contact or by calling 101, quoting incident number 19:270.