Steve Lowery was in the first group out Saturday morning and put together a round of 8-under 64. He is tied for second with Charles Howell III (67) and Harrison Frazar (68) at minus-16.
Heavy, swirling wind greeted the players on Saturday as play shifted to the TPC at Summerlin. That course hosts the final two rounds after the action was split between Summerlin and the TPC at the Canyons.
Purdy flew out of the gate on Saturday with four consecutive birdies to get to 15 under par for the championship. His strong play continued at the par-3 eighth when his tee ball tracked toward the cup before stopping a foot short. Purdy tapped in for his fifth birdie of the front nine.
Purdy collected an additional birdie on the front side at the par-5 ninth. He reached the green with his second and had 18 feet for eagle, but missed. Purdy tapped in for birdie to get to 17 under par and take a two-stroke advantage.
The wind was wreaking as much havoc as it could and Purdy nearly lost a shot at the 11th. He was able to save par from 10 feet, but missed a 5-footer for birdie at No. 12.
At the par-5 13th, Purdy was forced to lay up short of the green with his second. He hit his third to 4 feet and converted the die putt to get to minus-18.
Purdy missed the green at the par-3 14th and it cost him. He made bogey there, but atoned for the mistake one hole later. Purdy's approach at 15 nearly spun into the jar, but he settled for a 7-foot birdie to get back to 18 under par.
Purdy did not give himself many good looks at birdie on the way into the clubhouse until 18. He drove into the right rough and had over 200 yards to the hole. Purdy hit a 3-iron 25 feet from the flag, but his birdie try came up just short.
Despite not recording a birdie at the last, Purdy will take the 54-hole lead. He benefited from the wind not coming up until later in his front nine, when he already ascended to the top spot on the leaderboard.
'The wind came up about the seve' said Purdy. 'Fortunately, I was 4 under before that. I had the eighth hole, a long par-3, and it was straight downwind. That actually helped on that hole.'
Purdy broke through this season in a final-round battle with Sean O'Hair at the Byron Nelson. If the wind is up like it was on Saturday, Purdy is confident.
'I think it's the same kind of wind tomorrow, so it should be an interesting finish,' said Purdy. 'The only thing you can control is yourself and what you're doing. One shot at a time.'
Jim Furyk, a three-time winner of this event, shot a 3-under 69 and is tied for seventh place with Geoff Ogilvy, who posted a 5-under 67. The pair is knotted at 15-under-par 200.
Scott Gutschewski (67), Phillip Price (68), Ryan Palmer f Sluman (66), Hidemichi Tanaka (68) and Shigeki Maruyama (72) are tied for ninth at minus-13.
Briny Baird, who led after the opening two rounds, struggled in the wind on Saturday. He carded a 6-over-par 78 and fell into a tie for 43rd place at 9-under-par 206.