Porteous stunned the competition with a flawless fourth and final run, unleashing what commentators described as "one of the most technical runs ever" landed in the competition.
AP has Australia also winning three medals, two silvers and a bronze which would put them behind New Zealand on the table.
Norway is predicted to win 39 medals, the same tally that saw the country top the medal table in 2018, with USA one medal back with 38.
Hosts China is tipped to win 18 medals.
In the notable events, AP is tipping Canada to win both the women's and men's hockey golds with Russian Olympic Committee athletes expected to sweep the women's figure skating medals.