Secret Witness is offering a $1,000 reward for information in the whereabouts of a 19-year-old Petaluma, Calif., woman missing since she attended Snow Globe on New Year's Eve in South Lake Tahoe.Alyssa Byrne is 5 feet, 3 inches tall, and weighs 125 pounds. She has black hair and blue eyes, and was wearing a black sweatshirt, black yoga-type pants, and black snowboots. Her hair was pulled back.Friends told Douglas County Sheriff's officers they last saw her in the Horizon Casino at a bar between 12:30-1 a.m. on New Year's Day.Because circumstances of her disappearance are unknown, Douglas County Sheriff's Office …