Can you help find missing woman Jessica Mackay?

Surrey Police are  appealing for help in finding a missing woman from Guildford.

Jessica Mackay, 30, was reported missing earlier yesterday evening (4 January) just after 9pm.  
She is described as extremely vulnerable and officers are growing increasingly concerned for her welfare.
A search of the Guildford area is currently underway. Jessica is also believed to have links to the Staines and Shepperton areas and is known to travel by train. 
Jessica is described as white, around 170cm tall and of a slim build with dark brown hair. She is believed to have been wearing a long black jacket, blue trousers and black shoes when she was last seen.
Anyone with any information which could help to find Jessica is asked to contact Surrey Police straightaway on 101, quoting incident reference P17002890.