Thornton (NMMU) cleared 3.60 metres at her second attempt en route to the gold medal, which is just short of her personal best of 3.70m set in Stellenbosch three seasons ago.
Reigning South African champion Deone Joubert (UJ) will, in Thornton's book, start as the overwhelming favourite on Friday.
Joubert won the national title with a jump of 3.70m, but went on to set a personal best of 4.10m later in the season.
Honorata Saar (Tuks), the national Bronze medallist last year, is another of the fancied vaulters on the provisional entry list.
Thornton, the national Silver medallist in 2008, was hampered by a hamstring injury during the first part of last season, but came back well to win a Silver medal at the World Masters Games in Sydney in October.
She said her training had gone really well in the build-up to the first of six Yellow Pages Series events to be held around the country. “It is still early in the season, but I feel I'm in good shape.”
She said it was difficult to predict how Friday would go.
“It is such a technical event and much depends on the weather conditions. I will focus on clearing a good height and hopefully the result will take care of itself.”
Thornton said it was a huge privilege for a local athlete to be invited and she hoped for a good performance in front of her home crowd. “It is always nice to have an audience.”
World 800m champion Mbulaeni Mulaudzi and national steeplechase record-holder Ruben Ramolefi have both been confirmed for the meeting.
The event, which takes place at the Xerox NMMU Stadium, will kick-off with a pre-programme consisting of school relays at 4pm. The main programme gets underway at 6pm.
Tickets will be available at the gate before the start. The cost is R10 for adults, while scholars and students may enter for free.
