Sally, aged 59, was last seen at about 6am in Draycott, near Cheddar.
It is believed she was wearing a black embroidered top, black skinny trousers and flip flops when she went missing.
An Avon and Somerset Police spokesperson said Sally is described as white, female, of average build, approximately 5ft 6in tall and with long hair.
If you see her, you should call 999 immediately giving the call handler the reference number 5223192909.
If you have any information about Sally, you should call police on 101 giving the same reference number.