Savannah Guthrie has made a new public appeal for information about her missing mother, Nancy Guthrie, as the search continues nearly six months after her disappearance. The NBC “TODAY” co-anchor shared an emotional video message on social media Monday, asking the person responsible for her mother’s disappearance to provide information and help bring the case to an end. “I’m coming on today with a very specific message,” Guthrie said in the video. She explained that her family…